Dry Trans

Dry Type TransformersSelection and Application Guide What is a Transformer? Transformers are completely static electrical devices which convert alternating current from one voltage level to another. General purpose transformers are rated 600 volts and below for supplying appliance, lighting, and power loads from electrical distribution systems. Standard distribution voltages are 600, 480, and 240 volts; standard load voltages are 480, 240, and 120 volts. The transformer is used to match the voltage supply to the electrical load. They can increase (step-up) or decrease (step-down) voltages. Since no vaults are required for installation, dry type transformers can be located right at the load to provide correct voltage for the application. This eliminates the need for long, costly, low voltage feeders. Siemens general purpose transformers meet applicable NEMA, ANSI, UL, and IEEE standards. ANSI C89.2/NEMA ST 20 ANSI C57.12.91 ANSI C57.96 UL 506 UL 1561 Contents Overview Selection and Application Catalog Coding System Encapsulated Transformers Ventilated Transformers Single Phase and Three Phase Transformers KVA/Ampere Tables Electrostatic Shielded Non-Linear Loads Drive Transformers K-Factor Buck-Boost Transformers Industrial Control Circuit Transformers Glossary 1-3 4 5 6 7 8-10 8-10 11 12 13 14-15 16-21 22-26 27-29 What does a Transformer do? Principle of Operation Transformers operate on the principle of magnetic induction. They consist, in their simplest form, of two or more coils of insulated wire wound on laminated steel core. The current supplied to one coil, the PRIMARY or input, magnetizes the steel core, which in turn induces a voltage in the SECONDARY or output coil. The change of voltage from the primary to the secondary is proportional to the turns ratio of the two coils. For example, in the figure shown below, the cores input, or primary leg has twice as many turns as the secondary. This is a two-to-one transformer...any voltage fed into the system will be reduced by one half. In other words, if 480 volts are applied to the primary, 240 volts will be induced in the secondary. This is an example of a two winding “stepdown” transformer. If the voltage is to be “stepped-up” or increased, the same transformer could be turned around and connected so that the input side would have 240 volts and the output would be 480 volts. Standard transformers rated 3 KVA and larger can be used for either step-up or step-down service. Transformers rated 2 KVA and below have compensated windings and should not be used in reverse feed applications. 480 Turns Primary Autotransformers Standard transformers are referred to as insulating transformers, or isolation transformers, because the primary and secondary windings are separated by insulation. There is no electrical connection between the windings; the voltage is magnetically induced between the primary and secondary. As such, twowinding transformers isolate the load circuit from the supply circuit. Autotransformers are specially designed transformers consisting of one continuous winding. The primary and secondary are electrically connected. The required secondary voltage is obtained by designing a tap at the appropriate turn location. Autotransformers can be used in three phase or single phase applications to perform the same function as two-winding transformers, with the exception of isolating two circuits. Since they are physically connected internally, autotransformers do not provide circuit isolation and in some cases, local codes may restrict their use. Standard Transformer H1 X1 Input Output H2 X2 240 Turns Secondary Autotransformer H1 Input Output X1 H2 X2 1 or 40°C maximum over a 24-hour period. saves energy. But. and 80°C rise are about 20-35% less than transformers with 150°C rise/220°C insulation system. °C -° F 0° . Rating of Design Operating Overload Insulation Temp. If the dual voltage is separated by an “X” (120 x 240). Insulation System Classification Maximum + Winding Ambient Rise 40°C 40°C 40°C 40°C 55°C 80°C 115°C 150°C + Hot Spot 10°C 30°C 30°C 30°C = Temp. Rise Temperature Capability 220°C 220°C 220°C 80 °C 115°C 150°C 150°C 185°C 220°C 30% 15% 0% Overload Capability Per ANSI loading guides. Each is made of materials that will withstand a certain temperature without shortening the life of the transformer. the transformer will provide the higher voltage (240 volts). the amount. the lower voltage (120 volts) is obtained. The temperature rise does not apply to the outside surface. or any part of the transformer– only the coil.104° 55° . Basic Impulse Levels Basic impulse level (BIL. and duration of loading cycles determine a transformer’s life. less heat generated.176° 90° . losses for 115°C rise are about 10-20% less. Each insulation system will withstand the following average temperature rise over a 40°C ambient as defined by ANSI (American National Standards Institute) and NEMA (National Electrical Manufacturers Association).96). This information is shown on the nameplate. Transformers can deliver short-term overloads without being damaged if the overload period is preceded and followed by reduced loads. Ambient Temperature and Altitude The ambient air temperature should not exceed 30°C average. voltages. or kv-BIL) is the ability of the transformer insulation to withstand high voltage surges due to switching or lightning. 120/240 or 120 x 240) may be connected either in series or in parallel per the connection diagrams. the core. the rise of the coil must not exceed 150°C. This means that regardless of the insulation system used.212° 105° . if it is separated by a “slash” (120/240). Connected in series. frequency.g. H4 X1 Input (Primary) H3 H2 X2 X3 Output (Secondary) H1 X4 Multiple (Parallel) Connection (typical) H4 X1 H3 X2 X3 Input (Primary) H2 Output (Secondary) 2 H1 X4 .428° When operated at rated KVA and temperature rise. lower operating costs.32° 10° . and the altitude should not exceed 3300 feet above sea level for normal operation. an additional connection is possible since the mid-point becomes available for 240/120 3-wire operation. transformers operating at their rated temperature rise will have essentially the same design life. Surface temperatures on transformers are established by Underwriter’s Laboratories (UL). • Additional capacity for emergency overloads. • Conserves electrical power. higher efficiency. when a 220°C rise insulation system is used.50° 30° . Reducing the temperature from 150°C rise provides several benefits: • Reduced losses. phase. 80°C Rise 40°C Maximum Ambient 80°C Winding Rise 30°C Hot Spot Allowance 70°C Reserve (30%) 220°C 110°C Hot Spot Rise (80°C + 30°C) 115°C Rise 150°C 40°C Maximum Ambient 30°C 115°C Hot Spot Winding Rise Allowance 145°C Hot Spot Rise (115°C + 30°C) 150°C Winding Rise 180°C Hot Spot Rise 35°C Reserve (15%) 185°C 220°C 150°C Rise 40°C Maximum Ambient 30°C Hot Spot Allowance 220°C Rating The transformer rating includes its KVA.302° 185° . connections.194° °C -° F 100° . and temperature rise. Class 105°C 150°C 185°C 220°C Low Temperature Rise Transformers rated 15 KVA and above using 220°C insulation can be designed for 115°C or 80°C winding temperature rise as an optional feature. connected in parallel.221° 115° .365° 220° . taps. Dry type 600 volt class transformers are rated 10 kv-BIL per industry standards. That is.86° 40° . Series-Multiple Connections Transformers with two identical voltages (e. Series Connection (typical) Temperature Rise The temperature rise for transformers is the average temperature rise of the aluminum or copper conductor inside the coil windings. • Longer expected transformer life.239° 150° .Overview.131° 80° . The temperature rise of the coil is set by the designer and must be compatible with the limit of the insulation system. frequency. the transformer can be connected only for 120 volts or 240 volts. (Reference ANSI C57. Selection and Application Insulation Systems There are four types of insulation systems commonly used in dry type transformers. Standard taps are two 5% below normal on most smaller transformers to provide a 10% range of tap voltage adjustment. use the following tips: 1.Voltage Termination Both high voltage and low voltage windings are terminated in the transformer wiring compartment.50 51 . Improper location and installation can increase the noise level 10 dB or more and cause complaints about transformer noise.300 301 .” ANSI and NEMA standards for average sound levels are shown below. 2. Transformers can be custom designed for sound levels below standard when specified.5% FCBN Figure B -5% -10% +5% +2. Make sure the area has proper air ventilation. H2. avoiding direct contact with other metal structures. sound levels above 70dB are considered annoying and 100 dB very loud. Make sure shipping braces and hold-down bolts are loosened or removed as specified by the manufacturer’s installation manual. Halls or small and narrow areas with short distance between multiple reflective areas will also amplify sound.used for measuring the loudness of sound. a typical classroom. H3.2. Curtains. X2. Isolate the transformer by using flexible couplings and conductors to help prevent vibrations being transmitted to other equipment. Mounting should be on a solid wall.5% FCAN 4 . Ventilated transformers should “float” on vibration dampening pads located between the enclosure and the core and coil assembly. floor.5% FCBN Figure A 2 . and other ceiling or wall sound treatments are generally not effective barriers to transformer noise. the adjacent surfaces act as a megaphone. Generally. The ambient sound level.four 2-¹⁄₂% below normal and two 2-¹⁄₂% above normal for a 15% range of tap voltage adjustment. 5. the actual number of taps and the tap ratio may vary based on the volts per turn ratio required for the design. For some ratings. Sound Levels All transformers that are energized will produce an audible noise that sounds like a “hum. (3 dB increase = 2x sound volume.5% -2. Install the transformer so that vibrations are not transmitted to the structural parts of the building.2/NEMA ST20 (150°C RISE K-1) Reducing Noise Levels The sound level of background music. Locate the transformer where sound is not significantly increased by sound reflection. or other structure with solid mass. Transformer noise can be reduced in a closet or behind a wall if the wall has no openings and is not subject to vibrations from the transformer. Voltage Changing Taps Taps are frequently added on the primary winding to change the turns ratio and compensate for high or low line voltages. X3 and the neutral as X0. 3.500 501 .2. The high voltage terminations are identified in accordance with NEMA standards as H1. or background noise can reach 90 dB in typical industrial locations. Locate the transformer away from areas where noise is undesirable. When transformers are mounted in a corner or near the ceiling. 4.1000 Average ambient sound level of typical locations Œ ANSI C89. The connection diagram on the transformer nameplate shows the proper connections for series or multiple connections and tap settings. To achieve a “quiet” transformer installation. or conversation at 3 feet is about 60 dB.5% -5% -7.150 151 . Most larger transformers have six taps . Rated Line Voltage Taps 2 . Mounts must be isolated and properly loaded. the low voltage leads as X1. The number of taps and the tap ratio depend on the KVA size and the design volts per turn ratio.700 701 . screens.) KVA 0-9 10 . Average dB Sound Level Œ 40 45 50 55 60 62 64 80-90 dB* 65-75 dB* 50-70 dB* 45-60 dB* 25-50 dB* Office Retail Average Factory Office without store home with at night machines machines *decibels .5% -10% 120 114 108 126 123 117 114 111 108 208 198 187 218 213 203 198 192 187 240 228 216 252 246 234 228 222 216 277 263 249 291 284 270 263 256 249 480 456 432 504 492 468 456 444 432 600 570 540 630 615 585 570 555 540 Figure A (typical) X1 H1 Figure B (typical) H1 504V 492V X1 120 Turns 480V 480V 120V 468V 456V 240V 120 Turns X2 120V 456V X2 480 Turns 480 Turns 444V 432V 240V X3 X3 120 Turns 120V 120 Turns 432V 120V H2 X4 H2 X4 3 . the power factor of the load must be considered. Refer to NEMA ST20 and ANSI C57. 60 Hz 480 volts. both the supply and transformer must be three phase. Transformers can be operated stepdown or step-up provided the rated nameplate KVA is 3 KVA or greater. some provision for future increase in load should be made when selecting the transformer.732. with three phase delta wye models. The neutral (XO) is not needed in this application. Special transformers are normally required for such applications. or 480 volts primary. For three phase applications. the load voltage will not match the nameplate value. Transformers rated to carry 60 Hz should not be used on other frequencies. Also. the supply must also be rated 60 Hz. In most cases. The same principle applies to load voltage. with taps is suitable. the current required to deliver rated motor horsepower dictates the minimum transformer KVA required. When using transformers in reverse (step-up). Be on the alert for high ambient temperatures (above 40° C). and high humidity or saltspray conditions. The next largest standard single phase unit is 7-¹⁄₂ KVA. If not. If the load is three phase. Depending on KVA size. The transformer will now be the equivalent of a delta-delta connection. which allows for future load expansion. Below 3 KVA. Special Applications If the transformer is to be installed outdoors. Divide the 4 . If these transformers are reverseconnected. Frequency and Phase The transformer cannot change the frequency of the supply. multiply load current times load voltage times 1. if maximum load current is 50 amps and load voltage is 120.96 for high ambient or high altitude applications. If load requirements are given in watts. It should be insulated and not connected to the input source neutral if one exists. Transformers rated 50 Hz can be used for either 50 or 60 Hz.Selection and Application Selection Factors The most important thing to remember when selecting a transformer is to choose a unit that matches supply and load conditions. the transformer primary must match the line voltage. high altitude conditions (above 3300 feet). but the transformer will be single phase. single phase. it must be suitable for outdoor application.000 VA or 6 KVA. You must first determine: Line (available) Voltage Frequency Phase Load (needed) KVA Voltage Frequency Phase watts by the power factor to determine VA capacity: VA capacity = Watts Power Factor KVA capacity = KW Power Factor When motors are installed in the circuit. Selecting Voltage Ratings Next select the proper line and load voltages. If the load is single phase. the supply can be either single or three phase. the requirement is 6. a transformer rated 240 x 480 volts primary. For example. Single phase: KVA = (FLA x Volts) ÷ 1000 Three phase: KVA = (FLA x Volts x 1.732) ÷ 1000 Usually. The transformer must have this minimum nameplate capacity in volt-amps (or KVA if voltamps has been divided by 1000). For example. maximum load current multiplied by the load voltage gives volt-amp capacity for single phase applications. it the load is rated 60 Hz. In single phase circuits. remember that the normal primary taps will now be on the secondary. Selecting Transformer KVA Rating You will usually know your load requirements. the transformers usually have compensated windings to provide rated voltage at rated load. the neutral of the 4-wire secondary winding will now be on the primary side. Therefore. the actual load voltage could be up to 15 per cent lower than expected. you will already know the power supply and load ratings. if the line voltage is rated single phase. 75 1 1.1% (2 FCAN.5% FCBN 6 . 1 FCBN) 3 .5 % FCBN 2 .See Page 15.5% (1 FCAN.5 150 Catalog Code 037 045 050 075 100 112 150 KVA 167 225 300 500 750 1000 Catalog Code 167 225 300 500 750 1000 Œ Actual taps may vary based on volts/turn ratio.5% (2 FCAN.115°C Rise ES .Drip Shield (NEMA 3R) KVA KVA 0.2. 4 FCBN) 4 . 2 FCBN) 2 .Copper Windings LN( ) . ETC. Phase 1 Phase 3 Phase 1 3 240 x 120 208 240 480 x 240 Primary A B C D Secondary 277 480 600 E F G 120/240 240/120 LT 240 208Y/120 480 480Y/277 1 1 2 3 4 5 Œ Suffix code for optional information indicated in parentheses.5 45 50 75 100 112.50% Non-Linear Load K13 .25 0.2.) WALL MOUNTING BRACKETS (W) DRIP SHIELDS (DS) Drive Transformer Catalog Coding .Wall Brackets DS .100% Non-Linear Load K20 .150% Non-Linear Load B . 1 FCBN) 4 .3. 5 . Taps Œ Description None 2 . 2 FCBN) Catalog Code N R S T U X Y J K M Optional Modifications K4 .Totally Enclosed Non-Ventilated W .3. Other optional modifications must be specified.5% (2 FCAN.5 2 3 Catalog Code 205 505 705 001 105 002 003 KVA 5 7.80°C Rise F .Electrostatic Shield C .2.125% Non-Linear Load K30 .5% FCBN 4 .2. 2 FCBN) 2 .Low Noise (specify dB level) TE .5% (1 FCAN.50 0.5 9 10 15 25 30 Catalog Code 005 007 009 010 015 025 030 KVA 37.Catalog Coding System 1 D 1 Y 167 K4 F ES C LN3 W DS Basic Rating Information PHASE PRIMARY VOLTAGE SECONDARY VOLTAGE TAPS KVA Optional Modifications Œ K-FACTOR RATED 50% Non-Linear Load (K4) 100% Non-Linear Load (K13) 125% Non-Linear Load (K20) 150% Non-Linear Load (K30) LOW TEMPERATURE RISE 80°C (B) 115°C (F) L Add suffix codes if optional modifications required ELECTROSTATIC SHIELD (ES) COPPER WOUND (C) LOW NOISE (SPECIFY LN3 LN5.5% (1 FCAN. • Core and coil completely embedded within a resin compound for quiet. heavy gauge steel enclosure.050 . • Efficient.0 KVA Single Phase 3. non-ventilated. • Flexible wiring leads that terminate within the bottom wiring compartment. dust. IEEE standards.3. • High quality non-aging electrical grade core steel.15 KVA Three Phase Features • UL listed designs which comply with applicable ANSI. and corrosion. lightweight. Wiring compartment for encapsulated transformer 6 . compact. • Rugged design resists weather. • UL listed indoor/outdoor enclosure features integral wall mounting brackets. • Encapsulation seals out moisture and air. • Precision wound coils. NEMA.0 .Encapsulated Transformers . • Large wiring compartment on the bottom with convenient knockouts. low temperature operation. easy to install. • Totally enclosed. NEMA.1000 KVA Three Phase Features • UL listed designs which comply with applicable ANSI. Ž For units having standard features. Optional Accessories Wall Mounting Brackets Ž 1 Phase 3 Phase Drip Shield Kits Œ 1 Phase 3 Phase 15-50 KVA 15-50 KVA Wall Mounting Brackets 15-167 KVA 15-225 KVA  Œ NEMA 3R outdoor rated transformer with installation of optional drip shield kit. standard units feature 150°C winding temperature rise. • Precision wound coils.Ventilated Transformers 15 . Wiring compartment for ventilated transformer Drip Shield Kits 7 .167 KVA Single Phase 15 . • Designed for indoor installation: enclosures suitable for outdoor locations available as an option.  Contact sales office for kits used on larger ratings. • Core and coils are designed with UL listed high-temperature materials rated for 220°C. • Neoprene noise dampening pads isolate the core and coil from the enclosure. • Optional low temperature rise of 115°C or 80°C winding temperature rise for increased efficiency and additional overload capability. • High quality. • Rugged 12 gauge sheet steel enclosure with removable panels for access to the internal wiring area. non-aging electrical grade core steel. • Optional drip shields and wall brackets available on most ratings. and IEEE standards. • Totally enclosed Non-Ventilated designs available as an optional feature on most ratings. 0 1.8 6.4 2.5 112.0 260.0 — — — 3 3 3 3 6 6 9 15 15 30 30 45 45 75 75 — — — 220-240V Single Phase Three Phase Amps KVA Amps KVA 4. or cycles per second.3 8.1 1.2 16.25 .0 77.0 4. Determine the electrical supply.4 1.4 3.9 6.0 7. 8 .0 52.0 3. the transformer.0 3.0 124.8 7.0 84.5 112.5 Horsepower ¹⁄₂ ³⁄₄ 1 1 ¹⁄₂ 2 3 5 7 ¹⁄₂ 10 15 20 25 30 40 50 60 75 100 Œ Recommended KVA rating shown in chart includes aluminum of 10% spare capacity for frequent motor starting.0 5.0 5.9 1.0 7.5 37.6 5.5 50 75 — — — 2.5 14.6 14.0 40.6 3.0 86.5 3.0 22.0 52.0 3 3 3 3 6 6 9 15 15 30 30 45 45 75 75 75 112. a) Check the primary source (input) voltage available.0 136.0 7.1 4.0 5.2 10.0 3.0 4.0 80.0 108.0 68.Steps To Select Single Phase and Three Phase Transformers Single Phase Transformers 1. d) Select a transformer with a KVA capacity equal to or greater then the required load.0 3 3 3 3 6 6 9 15 15 30 30 45 45 75 75 75 112.6 2.0 27 36 54 90 135 180 270 361 603 903 1202 1805 480V 0.4 13. 2.0 21.2 4.0 1.8 3.0 2.0 136.0 5.0 88.0 65.0 44.0 17.2 10.1 4.0 — — — 1.8 31 41 62 104 156 208 312 416 695 1041 1387 2063 277V 0.0 3 3 3 3 6 6 9 15 15 30 30 45 45 75 75 75 112.1 3.5 4.8 3.0 5.5 15 15 25 25 37.0 42.7 25 41 62 83 125 166 278 416 555 833 AC Motor Full Load Running Current and Recommended Transformer Ratings Œ 110-120V Single Phase Three Phase Amps KVA Amps KVA 9.0 50.0 26.5 440-480V Single Phase Three Phase Amps KVA Amps KVA 2.0 2.2 10.5 2 3 5 7.5 2.0 28.0 3.6 5.0 6. or KVA capacity required by the load.0 40. increase corresponding 220-240 volt ratings by 15 and 10% respectively.3 12.0 5.0 41.0 34.0 14.6 15.5 15 15 25 25 37.0 3. b) Load ampere.0 104.3 12.3 1.8 7.0 100.0 108.8 18.0 154.0 35.2 6.7 25 41 62 83 125 206 312 416 625 833 1391 2063 2775 4167 Single Phase Full Load Amperes 208V 1.0 68.5 50 75 100 167 250 333 500 120V 2.2 30. c) Verify the load is designed to operate on the same phase and frequency that is available.7 2.0 80.0 130.0 34.0 — — — 1.7 3. KVA .3 5 8.0 216.0 27.0 5.0 7.0 5. Determine the electrical load.5 37.4 0.0 55.3 12.2 6.0 20.0 3. a) The secondary voltage or load (output) voltage required.0 12.6 4.0 99.5 2.8 1.8 1.8 11.5 10 15 25 37.0 — — — — — — — — 1.0 10.5 1.0 3.8 9.6 20.0 28.  To obtain full-clad currents for 200 and 208 volt motors.6 11.0 — — — 1.0 56.5 50 75 — — — 0.0 5.4 7. and the load equipment must be the same.0 5.9 6.5 550-600V Single Phase Three Phase Amps KVA Amps KVA 2. e) Use charts.0 11.2 9. The frequency of the primary line supply.8 2.8 13.0 70.2 2.5 37.1 9.5 16.0 62.9 8.0 160.0 27.0 88.0 54.1 3.5 3.5 15 15 25 25 37.0 68.0 21.6 7. b) Check the frequency in hertz.2 6.5 16.8 2.0 77.0 5.0 27.5 20.0 8.75 1 1.4 44.5 2.0 135.6 19. or calculate the load as follows: 1 Phase KVA = Volts x Amps 1000 Load Amps = 1 Phase KVA x 1000 Volts f) Determine taps to compensate for line voltage variation and temperature rise requirements.5 2.4 24 36 48 72 120 180 240 340 480 803 1202 1601 2404 240V 1.4 4.0 32.2 8.0 34.50 .0 56.0 208.0 192.0 3.1 2.8 16.4 15.0 2.2 22.5 15 15 25 — — — — — — — — 4.0 44.0 110.7 3.0 176.0 96.2 6.0 248.0 24.5 50 75 — — — 1.0 20.5 112.8 31 52 76 104 156 208 347 520 695 1042 600V 0.0 17. 9 .5 1B 1N007 None 10 1B 1N010 None 15 1B 1N015 None 25 1B 1N025 None 277 Volts Primary.5% FCBN 2 .0 1D 1N002 None 3.25 1D 1N205 None .5 1D 1N105 None 2.5 1F 1R007 2 .2¹⁄₂% FCBN 2 .0 1D 1N001 None 1.5% FCBN 2 .5% FCBN 10 1F 1R010 2 .5% FCBN 2 .2¹⁄₂% FCBN 2 .5% FCBN 7.2¹⁄₂% FCBN 2 . 120/240 Volts Secondary 3 5 7.5% FCBN 5 1F 1R005 2 .2¹⁄₂% FCBN Œ Actual taps may vary based on volts/turn ratio. 120/240 Volts Secondary 3 5 7. 120/240 Volts Secondary .5% FCBN 2 .2¹⁄₂% FCBN 100 1D 1Y100 167 1D 1Y167 480 Volts Primary.2¹⁄₂% FCBN 2 .5 10 15 25 1E 1U003 1E 1U005 1E 1U007 1E 1U010 1E 1U015 1E 1U025 2 .5% FCBN 15 1F 1R015 2 .5% FCBN 600 Volts Primary.5 1D 1Y037 50 1D 1Y050 2 .Catalog Temperature KVA Number Taps Œ Rise 208 Volts Primary.0 1D 1N003 None 5.5 1D 1N007 None 10 1D 1N010 None 15 1D 1N015 None 25 1D 1Y025 37.2¹⁄₂% FCBN 2 .2¹⁄₂% FCBN 2 . 120/240 Volts Secondary 3 1B 1N003 None 5 1B 1N005 None 7.0 1D 1N005 None 7.5 50 75 100 167 1G 1R003 1G 1R005 1G 1R007 1G 1R010 1G 1R015 1G 1U025 1G 1U037 1G 1U050 1G 1U075 1G 1U100 1G 1U167 2 .5 10 15 25 37. 120/240 Volts Secondary 3 1F 1R003 2 .50 1D 1N505 None .2¹⁄₂% FCAN 75 1D 1Y075 4 .2¹⁄₂% FCBN 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 150°C 150°C 150°C 150°C 150°C 150°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 115°C 150°C 150°C 150°C 150°C 150°C 150°C Insulation 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 220°C 220°C 220°C 220°C 220°C 220°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 180°C 220°C 220°C 220°C 220°C 220°C 220°C 240 x 480 Volts Primary.2¹⁄₂% FCBN 2 .5% FCBN 2 .2¹⁄₂% FCBN 2 .2¹⁄₂% FCBN 2 .75 1D 1N705 None 1.2¹⁄₂% FCBN 2 . 2¹⁄₂% FCBN 112.5% FCBN 150°C 500 3B3S500 1 .32 12.9 43.5 150 225 300 500 Catalog Number 3F2R003 3F2R006 3F2R009 3F2R015 3F1Y015 3F1Y030 3F1Y045 3F1Y075 3F1Y112 3F1Y150 3F1Y225 3F1Y300 3F1Y500 Taps Œ 2 .732 1000 Load Amps = 3 Phase KVA x 1000 Volts x 1.1 54.5% FCAN 150°C 500 3B5S500 150°C 240 Volts Primary.2¹⁄₂% FCBN 1 .5% FCBN 2 . 208Y/120 Volts Secondary 15 3B3Y015 2 .6 25 41.5 150 225 300 500 3 6 9 15 15 30 37.5 3C3Y112 150 3C3Y150 225 3C3S225 1 . except use 3 phase Amps/KVA chart or calculate the load as follows: 3 Phase KVA = Volts x Amps x 1.2¹⁄₂% FCAN 150 3F5Y150 4 .4 48.5% FCBN 150°C 150 3B3Y150 2 .5% FCAN 300 3C3S300 1 .5 3B5R112 2 .5% FCBN 150°C 45 3B3Y045 2 .4 21.5 150 225 300 500 750 1000 3C5Y015 3C5Y030 3C5Y045 3C5Y075 3C5Y112 3C5Y150 3C5S225 3C5S300 3C5S500 3F3R003 3F3R006 3F3R009 3F3R015 3F3Y015 3F3Y030 3F3Y037 3F3Y045 3F3Y075 3F3Y112 3F3Y150 3F3Y225 3F3Y300 3F3Y500 3F3Y750 3F3Y000 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 115°C 115°C 115°C 115°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 180°C 180°C 180°C 180°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C Insulation 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C Three Phase Full Load Amperes KVA 3 6 9 15 30 45 50 75 112.  Reduced capacity 1 phase tap .1 72. 208Y/120 Volts Secondary 3 6 9 15 30 45 75 112.1 72 108 144 216 288 481 723 963 KVA 3 6 9 15 15 30 45 75 112.2 14.5% FCBN 2 .8 41.4 104 156 208 312 416 693 1040 1388 480V 3.2¹⁄₂% FCBN Œ Actual taps may vary based on volts/turn ratio.3 16.7 83.9 5.2¹⁄₂% FCAN 225 3F5Y225 300 3F5Y300 500 3F5Y500 600 Volts Primary.2¹⁄₂% FCAN 4 . 480/277 Volts Secondary 15 3F5Y015 30 3F5Y030 45 3F5Y045 75 3F5Y075 112.2¹⁄₂% FCAN 4 .5% FCBN 150°C 150 3B5R150 2 .5 3B3Y112 2 .5 3F5Y112 2 .16 8.4 124 139 208 312 416 624 832 1387 2084 2779 240V 7.732 Catalog Temperature KVA Number Taps Œ Rise 208 Volts Primary.5% FCBN 480 Volts Primary.0 36.4 69.6 36.3 108 120 180 270 360 541 721 1202 1806 2408 416V 4.5% FCBN 150°C 225 3B5S225 1 .5% rated KVA.5% FCBN 2 .5% FCBN 2 .5% FCAN 1 .5% FCBN 150°C 75 3B5R075 2 .5% FCBN 2 .5% FCBN 2 .2¹⁄₂% FCAN 75 3C3Y075 4 .5% FCBN 150°C 75 3B3Y075 2 . 240 Volts Secondary 480 Volts Primary. 208Y/120 Volts Secondary 2 .4 20.5% FCBN 500 3C3S500 240 Volts Primary.5% FCBN 150°C 208 Volts Primary.5 150 225 300 500 750 1000 208V 8.5% FCBN 150°C 225 3B3S225 1 .5% FCBN 480 Volts Primary.5% FCBN 2 .2¹⁄₂% FCAN 4 .6 7.5% FCBN 2 .2¹⁄₂% FCAN 4 . 480Y/277 Volts Secondary 15 3B5R015 2 .2 10.8 18.2 60.2¹⁄₂% FCAN .2¹⁄₂% FCBN 2 .5% FCBN Temperature Rise 115°C 115°C 115°C 115°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 115°C 115°C 115°C 115°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C Insulation 180°C 180°C 180°C 180°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 180°C 180°C 180°C 180°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 480 Volts Primary.5 150 225 300 500 3G3R003 3G3R006 3G3R009 3G3R015 3G3Y030 3G3Y045 3G3Y075 3G3Y112 3G3Y150 3G3Y225 3G3Y300 3G3Y500 2 . 480Y/277 Volts Secondary 15 30 45 75 112.5% FCBN 150°C 300 3B3S300 1 .8 8.5% FCBN 150°C 112. 2 .5% FCBN 2 . 240 Volts Secondary with 120 Volt Lighting Tap  2 .4 28.5% FCBN 150°C 30 3B5R030 2 .6 14.5% FCBN 150°C 30 3B3Y030 2 .6 62.5% FCBN 150°C 112.5 45 75 112.5% FCAN 150°C 300 3B5S300 1 . 208Y/120 Volts Secondary 15 3C3Y015 30 3C3Y030 45 3C3Y045 2 .Three Phase Transformers To select Three Phase transformers follow the same steps as Single Phase.5% FCBN 2 .5% FCBN 150°C 45 3B5R045 2 .1 90 135 180 270 360 601 903 1204 600V 2. Unshielded Transformer Primary V Shielded Transformer Secondary Primary V Secondary 11 . However. But today. Shielded isolation transformers do not provide voltage regulation. Shielded isolation transformers are typically used where load equipment is sensitive to transients or to suppress transients from back-feeding onto the feeder circuits. Electrical noise can be classified as either “common” or “transverse” mode. The following table outlines some common attenuating ratios and their decibel equivalents.Electrostatic Shielded Œ KVA 3 5 7. The formula used in measurement of transient noise attenuation is logarithmic and hence a change of 40 dB to 60 dB is actually a ten fold reduction in electrical noise. Noise Attenuation (dB) = 20 log10 V in V out Single Phase .Electrostatic Shielded Electrical noise and transients on power lines can be created by a number of different sources.5 10 15 25 37. Some examples are: lightning strikes. Transient noise is usually measured in decibels (dB). The amount of transient noise attenuation depends on the transformer design.000:1 Œ Common mode. switching or motor loads or capacitors. Electronic circuitry can be sensitive to transient noise and these transients have to be controlled. electronic components and systems are being used increasingly in many types of equipment destined for commercial and industrial installations.000. Voltage Ratio V in : V out 5:1 10:1 100:1 1.5 50 75 100 167 208 120/240 1B1N003ES 1B1N005ES 1B1N007ES 1B1N010ES 1B1N015ES 277 120/240 1E1R003ES 1E1R005ES 1E1R007ES 1E1R010ES 1E1R015ES 480 120/240 1F1R003ES 1F1R005ES 1F1R007ES 1F1R010ES 1F1R015ES 240x480 120/240 1D1N003ES 1D1N005ES 1D1N007ES 1D1N010ES 1D1N015ES 1D1Y025ES 1D1Y037ES 1D1Y050ES 1D1Y075ES 1D1Y100ES 1D1Y167ES 600 120/240 1G1R003ES 1G1R005ES 1G1R007ES 1G1R010ES 1G1R015ES 1G1U025ES 1G1U037ES 1G1U050ES 1G1U075ES 1G1U100ES 1G1U167ES — — — Three Phase . These types of noise have been around since electricity was first used. whereas transverse-mode noise appears between two line conductors. in this context.000:1 10. Common-mode noise is the type which appears between the line conductor and ground. but they do reduce electrical noise by attenuating spikes and transients to ground. Transient Noise Attenuation (dB) Œ 14 20 40 60 80 100 120 An optional feature for isolation transformers is to include an electrostatic shield between the primary and secondary windings.5 150 225 300 500 208∆ 208Y/120 — 3B3Y015ES 3B3Y030ES 3B3Y045ES 3B3Y075ES 3B3Y112ES 3B3Y150ES — 208∆ 480Y/277 — 3B5Y015ES 3B5Y030ES 3B5Y045ES 3B5Y075ES 3B5Y112ES 3B5Y150ES 3B5S225ES 3B5S300ES 3B5S500ES 480∆ 208Y/120 3F3R003ES 3F3R006ES 3F3R009ES 3F3Y015ES 3F3Y030ES 3F3Y045ES 3F3Y075ES 3F3Y112ES 3F3Y150ES 3F3Y225ES 3F3Y300ES 3F3Y500ES 480∆ 240∆ 3F2R003ES 3F2R006ES 3F2R009ES 3F1Y015ES 3F1Y030ES 3F1Y045ES 3F1Y075ES 3F1Y112ES 3F1Y150ES 3F1Y225ES 3F1Y300ES 3F1Y500ES 480∆ 480Y/277 — 3F5Y015ES 3F5Y030ES 3F5Y045ES 3F5Y075ES 3F5Y112ES 3F5Y150ES 3F5Y225ES 3F5Y300ES 3F5Y500ES Œ Refer to page 5 for other optional modifications.000:1 1. they were of little concern where traditional electromechanical devices were used.000:1 100. but a typical or “standard” shielded isolation transformer will provide about 60 dB attenuation (10 KHz -10 MHz). Decibel is a unit of measurement. and SCR circuits. used to express the ratio between the input transient voltage and the output transient voltage.Electrostatic Shielded Œ KVA 3 6 9 15 30 45 75 112. the use of electronic equipment proliferated in both offices and industrial plants. HID lighting. Fundamental 2nd Harmonic 3rd Harmonic* 4th Harmonic 5th Harmonic 6th Harmonic* 7th Harmonic 8th Harmonic 9th Harmonic* *Triplen Harmonic 60Hz 120Hz 170Hz 240Hz 300Hz 360Hz 420Hz 480Hz 540Hz thus reducing efficiency and shortening the life expectancy of the transformer. Examples of these devices used in offices are: computers.” the resultant current waveform takes on the shape of a sine wave as well.. which can be specified with the appropriate K-Factor rating. etc. many concerns are raised about its impact on the electrical supply system. or • Changes the impedance during the cycle. The percent of odd harmonics (3rd. As the use of electronic equipment increases and it makes up a significant portion of the electrical load. Typical linear loads are resistive heating and induction motors.Non-Linear Loads What Are Non-Linear Loads? When a sinusoidal voltage is applied to a “linear load. What Are Harmonics? As defined by ANSI/IEEE Std. 5th. 7th. In recent years. Furthermore.) present in the load can affect the transformer... This may cause installations with non-linear load to be double either the size or the number of neutral conductors... These electronic devices are powered by switching power supplies or some type of rectifier circuit. UPS and solid-state ballasts. the phase currents are 120 degrees out of phase and they offset one another in the neutral conductor. etc. They all contribute to the distortion of the current waveform and the generation of harmonics. distorting it and changing its magnitude. solid-state starters and solid-state instruments. copiers. In contrast. cash registers. on a balance linear power system. non-linear load either: • Draws current during only part of the cycle and acts as an open circuit for the balance of the cycle. Harmonics superimpose themselves on the fundamentals waveform. In industrial plants..25th. the fundamental and harmonic frequencies are outlined in the table below. 519-1981. and this condition is called a “Non-Linear Load” or “Non-Sinusoidal Load. one will find other electronic devices like variable speed drives. Effect Of Harmonics On Transformers Non-sinusoidal current generates extra losses and heating of transformer coils . printers. Coil losses increase with the higher harmonic frequencies due to higher eddy current loss in the conductors..” The total amount of harmonics will determine the percentage of non-linear load. But with the “Triplen” harmonics (multiple of 3) the phase current are in phase and they are additive in this neutral conductor. Plus 3rd and 5th Harmonic Components fundamental 3rd harmonic 5th harmonic Harmonics For 60 Hz Systems In a 60Hz power system. 12 Voltage or Current Waveform for Linear Loads (Sine Wave) Typical Current Waveform of Switching Power Supply A Non-Linear Current and Its Fundamental. fax machines. hence the resultant waveform is distorted and no longer conforms to a pure sine wave shape. harmonic components are represented by a periodic wave or quantity having a frequency that is an integral multiple of the fundamental frequency. 13 . and KVA ratings. Ampere.5% FCAN/BN 1 .Motor Drive Isolation Transformers With today’s technological advances in solid-state power control devices. KVA 7. AC and DC variable speed motor drives have become more popular in many industrial applications. an optional electrostatic shield can be provided between the primary and secondary windings to provide additional noise attenuation.5% FCAN/BN 1 .5% FCAN/BN 1 . The cores are designed with reduced flux density to meet the inrush characteristics of drive applications.5% FCAN/BN 1 .7.5% FCAN/BN 1 .P.5% FCAN/BN 1 .5% FCAN/BN 1 .5 10 15 20 25 30 40 50 60 75 100 125 150 200 250 300 400 500 600 Catalog Number DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( DT( )007 )011 )015 )020 )027 )034 )040 )051 )063 )075 )093 )118 )145 )175 )220 )275 )330 )440 )550 )660 Standard Taps Œ 1 .5% FCAN/BN 1 . Windings are braced to withstand the mechanical stress and overload capacity needed for motor drive and SCR duty cycles.5% FCAN/BN 1 .5 thru 330 KVA Thermal Switches Œ Standard taps varies with KVA size based on the design volts/turn ratio.7.5% FCAN/BN 1 .5% FCAN/BN 1 .5% FCAN/BN 1 .5% FCAN/BN 1 .5% FCAN/BN 1 . Siemens Drive Isolation Transformers are designed to meet the rugged demands of AC and DC variable speed drives and to provide circuit isolation from SCR’s. The separate primary and secondary windings provide electrical isolation between the incoming line and the load which minimizes line disturbances. Also available as an option is a thermal switch with 1-NC contact installed in each coil.5 thru 51 KVA Drip Shields . Ž For outdoor application.5% FCAN/BN 1 .  Refer to page 8 for additional information on horsepower.5% FCAN/BN 1 .5% FCAN/BN Temperature Rise 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C 150°C Insulation 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C 220°C Mounting Type Floor & Wall Floor & Wall Floor & Wall Floor & Wall Floor & Wall Floor & Wall Floor & Wall Floor & Wall Floor Floor Floor Floor Floor Floor Floor Floor Floor Floor Floor Floor Drip Shield Required Ž Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes DT( )Code 22 24 42 44 52 54 Primary Volts 230 Delta 230 Delta 460 Delta 460 Delta 575 Delta 575 Delta Secondary Volts 230Y/133 460Y/266 230Y/133 460Y/266 230Y/133 460Y/266 Suffix Code ES W DS TS Optional Modification Electrostatic Shield Wall Mtg.5% FCAN/BN 1 . feedback. They also provide the specific horsepower rating and voltage change to match the motor drive system. Brackets . and transients caused by SCR firing.5 11 15 20 27 34 40 51 63 75 93 118 145 175 220 275 330 440 550 660 Motor H. When needed.  3&5 7.5% FCAN/BN 1 .5% FCAN/BN 1 . 333% 7.250 2.667% 5.000 1.000% 30.250 0.250 0.824% 7.000 1.250 0.020 K-Factors K-Factor is a ratio between the additional losses due to harmonics and the eddy losses at 60Hz. the extent of the harmonics can be measured with appropriate instruments like “Power Harmonic Analyzer. It is used to specify transformers for non-linear loads.056 0.000 0.067 0.074 0.167 0.111% 9.500 0.000% I(pu) 1.043 0.417 0. 50% Non-Linear Load (K4 Rating) Harmonic (h) 1 3 5 7 9 11 13 15 17 19 21 23 25 Current (I) 100.333% 20.033 0.538% 10.143% 6.632% 2.762% 4. 14 . they withstand nonlinear load condition without overheating.250 0.000% 14.250 2.139 0.563 1.060 I(pu)2h2 1.096 0.054 0.038 0.250 K-Factor ∑(1h(pu)-h) = 4.050 I(pu)2h2 1.053 0. For new construction.079 0.110-1986 has a procedure on de-rating standard distribution transformers for non-linear loading.522% 6.179 0.651% 8. actual values may vary.333 0.263% 4.000 2.091 0.214 0.0 1.071 0.563 1.000 0.059 0.000 1.563 1. the percentage of fundamental.174% 2.563 1.114 0.088 0.429% 16.100 0.250 2.250 0.000% I(pu) 1.000 1.563 1.692% 6.300 0.563 1.143 0.250 K-Factor ∑(1h(pu)-h) = 28.756 Note: In the examples above the amount of non-linear load specified.895% 7. However. and the percentage of harmonic factor are arbitrary values.636% 11.167 0. Consult sales office for your specific application with current values for each harmonic. this is not the only approach.250 0.000 0.071 0.0 30.000% 17.000% I(pu) 1.250 2.000% 7.077 0.115 0.111 0.091% 7.952% 5.250 0.0 100% Non-Linear Load (K13 Rating) I(pu) h 2 2 Harmonic (h) 1 3 5 7 9 11 13 15 17 19 21 23 25 Current (I) 100.941% 2.250 2. such information may not be obtainable.000% 21.250 2.000 1.250 2.022 0.000% 16.” This service is offered by many consulting service organizations.143% 5.889% 11.066 0.000 1.545% 3.250 2.065 0.667% 10.846% 3.563 1.0 K-Factor ∑(1h(pu)-h) = 19.000 1.000 1.435% 5. A transformer with the appropriate K-Factor specifically designed for non-linear loads can be specified.000 1.364% 9.000% 33.250 0.286% 11.563 1.381% 2.000 1.100 0.0 20.333% 2.000% I(pu) 1.060 0.563 1.200 0.083 0.250 2.000 0.857% 13.348% 4.000% 8. Note that K-Factor transformers do not eliminate harmonic distortion.556% 4.563 1. Sizing Transformers for Non-Linear Loads ANSI/IEEE C57.563 150% Non-Linear Load (K30 Rating) Harmonic (h) 1 3 5 7 9 11 13 15 17 19 21 23 25 Current (I) 100. Type K-4 K-13 K-20 K-30 Linear Load Load 100% 100% 100% 100% + Non-Linear Load 50% 100% 125% 150% K-Factor Value 4.000 1.0 13.882% 5.353% 6.045 0.250 2.250 2.563 1.040 I(pu)2h2 1.000% 41. hence it is best to assume the “worst case” condition based on experience with the type and mix of loads.024 0.667% 13.250 0.000 K-Factor ∑(1h(pu)-h) = 13.667% 25.000 1.029 0.579% 5.K-Factor Measurement of Harmonics For existing installations.250 0.048 0.000 1.000 0.136 0.026 0.0 125% Non-Linear Load (K20 Rating) Harmonic (h) 1 3 5 7 9 11 13 15 17 19 21 23 25 Current (I) 100.250 0.250 0.000% 50. 2¹⁄₂% FCBN Temp.K-Factor K-Factor 4 with Electrostatic Shield Œ KVA 15 30 45 75 112. Rise 150°C Insulation 220°C 2 . Standard Features • Designed to ANSI and NEMA Standards • UL K-Factor listed per UL 1561 • K-Factor rating designed to IEEE C57. Rise 150°C Insulation 220°C 2 .2¹⁄₂% FCBN 150°C 220°C 2 .5 150 225 300 500 480∆ 208Y/120 3F3Y015K20 3F3Y030K20 3F3Y045K20 3F3Y075K20 3F3Y112K20 3F3Y150K20 3F3Y225K20 3F3Y300K20 3F3Y500K20 Taps 2 .2¹⁄₂% FCBN Temp.2¹⁄₂% FCBN Temp.2¹⁄₂% FCBN 150°C 220°C Œ Refer to page 5 for other optional modifications. 220°C insulation • Core.2¹⁄₂% FCAN 4 .5 150 225 300 500 480∆ 208Y/120 3F3Y015K4 3F3Y030K4 3F3Y045K4 3F3Y075K4 3F3Y112K4 3F3Y150K4 3F3Y225K4 3F3Y300K4 3F3Y500K4 Taps 2 .2¹⁄₂% FCAN 4 . Rise 150°C Insulation 220°C K-Factor 30 with Electrostatic Shield Œ KVA 15 30 45 75 112.5 150 225 300 500 480∆ 208Y/120 3F3Y015K30 3F3Y030K30 3F3Y045K30 3F3Y075K30 3F3Y112K30 3F3Y150K30 3F3Y225K30 3F3Y300K30 3F3Y500K30 Taps 2 .2¹⁄₂% FCAN 4 .2¹⁄₂% FCAN 4 .110 • Aluminum wound coils • 150°C Rise.5 150 225 300 500 480∆ 208Y/120 3F3Y015K13 3F3Y030K13 3F3Y045K13 3F3Y075K13 3F3Y112K13 3F3Y150K13 3F3Y225K13 3F3Y300K13 3F3Y500K13 Taps 2 . conductors designed for Harmonics and Eddy currents • 200% neutral bar (2x phase current) • Electrostatic shield to attenuate line transients • NEMA 1 enclosure Options • Other K-Factor ratings • Other voltage ratings • 80°C or 115°C temperature rise • Copper windings • Low noise • Drip Shields for NEMA 3R Enclosure • Wall Mounting Brackets (15-50 kVA) L 15 .2¹⁄₂% FCBN 150°C 220°C K-Factor 20 with Electrostatic Shield Œ KVA 15 30 45 75 112. Rise 150°C Insulation 220°C K-Factor 13 with Electrostatic Shield Œ KVA 15 30 45 75 112.2¹⁄₂% FCBN Temp.2¹⁄₂% FCBN 150°C 220°C 2 .2¹⁄₂% FCAN 4 .2¹⁄₂% FCAN 4 .2¹⁄₂% FCAN 4 .2¹⁄₂% FCAN 4 . Autotransformers are more economical and physically smaller then equivalent two-winding transformers and are designed to carry the same function as two-winding transformers. . A Buck-Boost Transformer will NOT. As insulating transformers these units can accommodate a high voltage of 120.00 1BB1632 1.00 3BB1632 5. When the supply voltage is constantly too high or too low (usually greater than + 5%) the equipment fails to operate at maximum efficiency.00 3BB1224 5. stabilize a fluctuating voltage. 240.750 705BB1224 1. care should be taken to assure that they are acceptable to local code. however. Buck-Boost transformers are suitable for use as a three phase autotransformer bank in either direction to supply 3-wire loads.150 150BB1224 .250 205BB1632 . They are NOT suitable for use in a three phase 120 x 240 Pri.Buck-Boost Transformers Application The Buck-Boost Transformer has four separate windings.750 705BB1632 1. KVA Catalog Number . They are also suitable for use in a three-phase autotransformer bank which provides a neutral return for unbalanced current.00 5BB2448 16 . or two 24 volt secondaries.16/32 Sec.100 100BB2448 . they may be prohibited in some areas by local building codes.00 1BB1224 1. Since autotransformers may transmit line disturbances directly. When connected in either the Buck or Boost mode.100 100BB1632 . For units with two 12 volt secondaries. the unit is no longer an insulating transformer but is an autotransformer.00 2BB1632 3.050 050BB1224 . KVA Catalog Number .00 3BB2448 5.500 505BB1224 . or for 3-wire secondary. with the exception of isolating two circuits.00 5BB1224 autotransformer bank to supply a 4-wire unbalanced load when the source is a 3-wire circuit.00 2BB2448 3. Before applying them. A Buck-Boost transformer is a simple and economical means of correcting this off-standard voltage up to + 20%.00 5BB1632 240 x 480 Pri.12/24 Sec.50 105BB2448 2. The unit is rated (KVA) as any conventional transformer.050 050BB1632 .500 505BB1632 .100 100BB1224 . KVA Catalog Number .150 150BB2448 .50 105BB1632 2.250 205BB2448 .500 505BB2448 . Operation Electrical and electronic equipment is designed to operate on a standard supply voltage. two 16 volt secondaries. . 120 x 240 Pri. As an autotransformer the unit can be corrected to Buck (decrease) or Boost (increase) a supply voltage.00 1BB2448 1.00 2BB1224 3.250 205BB1224 . The unit is designed for use as an insulating fransformer or as an autotransformer. the output can be wired for either secondary voltage. two-windings in the primary and two-windings in the secondary.50 105BB1224 2.050 050BB2448 .750 705BB2448 1. Note: Autotransformers are not used in closed delta connections as they introduce into the circuit a phase shift which makes them uneconomical. or 480 volts.150 150BB1632 . .24/48 Sec. Follow the selected column down until you find either the load KVA or load amps of your application. For line/load voltage not listed on the selection tables. Not all leads are shown. Follow the column of your line/load voltage to the bottom to find the connection diagram for this application. 5. 17 . 2. use the pair listed on the table that is slightly above your application for reference. Available from electrical supply houses.The voltage at which your equipment is designed to operate. not just the name plate rating of the Buck-Boost transformer. Number of phases . 3. This is listed on the nameplate of the load equipment. determine: 1.This information usually can be found on the nameplate of the equipment that you want to operate. CAUTION: Refer to National Electrical Code Article 373-4 for determining wire bending space.The supply line frequency must be the same as the frequency of the equipment to be operated . Load KVA or Load Amps . 6. In Coming Power (Supply) Wires To Load Transformer lead (terminal) wires.C. Use quantity of Buck-Boost Transformer(s) indicated on chart for connection to be made. Wiring trough or box (not supplied with the transformer(s). Line/Load voltage combinations are listed across the top of the selection table. 90° Connectors may be used to save bending room.Single or three phase line and load should match because a transformer is not capable of converting single to three phase. a common application to make a single phase transformer connection from a three phase supply by use of one leg of the three phase supply circuit. 5. Choose the selection table with the correct number of phases for single or three phase applications. The selection is dependent on whether a Wye connected bank of three transformers with a neutral is required or whether an open Delta connected bank of two transform ers for a Delta connected load will be suitable.You do not need to know both . Select a line/load voltage combination which comes closest to matching your application. Buck Boost Transformer Buck Boost Transformer Buck Boost Transformer 2. If you do not find the exact value. (See N. Wiring trough or box cover is shown. Frequency . A hole is cut at the time of installation in the wiring trough or box to match the opening in the bottom of the transformer.E. Then apply the first formula at the bottom of the table to determine “new” output voltage. 4.E. Either can be input or output depending on Buck or Boost application.C. (See N.) "T" Connectors may be used to save bending room. go on the next highest rating.The voltage that you want to buck (decrease) or boost (increase). In the case of three phase loads either two or three single phase transformers are required as indicated in the “quantity required” line at the bottom of the table. This can be found by measuring the supply line voltage with a voltmeter. 7.either 50 or 60 cycles. Care must always be taken not to overload the leg of the three phase supply. How to Select the Proper Transformer To select the proper Transformer for Buck-Boost applications. Now follow the column across the table to the far left-hand side to find the catalog number and KVA of the transformer you need. This is particularly true in a Buck-Boost application because the supply must provide for the load KVA. The new KVA rating can be found using the second formula.one or the either is sufficient for selection purposes. NOTE: Connection diagrams show low voltage and high voltage connection terminals. Input line voltage . Load voltage . Quantity required may vary from quantity shown in this illustration. It is however. 3. 4.Typical Three Phase Buck-Boost Autotransformer Installation How to Use Selection Charts 1.) Bottom cover of transformer is not used. 88 2.00 KVA 3BB2448 3.11 91.38 9.17 2.39 3.51 6.50 7.54 125.02 45.50 33.75 2.33 D 237 .08 3.26 31.20 22.67 3 F 457 1.75 2.58 2.13 7.42 45.00 41.59 1.83 27.77 68.33 50.67 24.38 18.67 14.50 125.17 1.50 34.54 137.17 1.17 6.67 49.76 6.83 6.00 125.00 8.08 .63 34.33 1.67 55.00 91.50 KVA 2BB2448 2.25 4.93 83.50 12.00 50.84 4.26 6.83 4.88 4.66 28.25 8.92 2.25 17.25 33.67 13.77 62.17 2.33 3 E 229 1.13 10.67 7.72 183.50 10.00 458.00 83.250 KVA 505BB2448 .21 137.56 208.75 23.17 45.83 7.15 34.50 52.81 91.00 60.75 20.63 21.00 25.92 416.30 6.50 131.15 31.75 31.66 15.04 4.66 30.00 8.05 175.43 6.54 6.26 229.16 1.95 4.00 43.75 36.57 262.53 6.07 83.00 KVA 105BB2448 1.15 8.42 4.13 5.09 22.50 31.94 20.00 50.13 11.75 10.00 83.00 94.32 41.17 1.17 1.50 43.33 45.00 86.50 92.33 2 G 229 .88 2.00 23.47 41.60 208.83 24.63 68.50 50.00 19.16 1.00 183.73 4.52 62.00 150.83 11.51 45.08 .67 25.00 208.15 4.67 49.58 1.50 4.08 1.66 A 208 .64 83.06 166.00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps 189Y 109 195Y 113 200Y 115 Boosting 208Y 120 416Y 240 416Y 240 Bucking 189 208 220 218 229 250 255 264 208 1.33 30.92 13.00 125.30 4.81 62.750 KVA 1BB2448 1.17 83.25 4.42 8.05 208.83 3.29 .01 41.50 2.33 2 G 242 .33 D 229 .33 99.99 31.75 4.60Hz .50 22.33 83.02 83.17 .54 11.75 20.13 62.69 4.50 105.33 31.58 1.25 63.08 1.50 45.59 250.50 62.02 83.20 62.48 2.56 6.60 41.No Taps .19 62.50 30.83 16.92 7.67 15.42 208.75 20.00 166.00 262.00 275.100 KVA 150BB2448 .50 20.52 2.500 KVA 705BB2448 .53 68.25 16.67 54.00 47.30 68.56 229.10 31.88 4.50 90.50 10.00 41.500 KVA 705BB2448 .50 20.06 137.08 1.64 65.73 13.67 3 F 234 .00 KVA 3BB2448 3.42 7.53 41.00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps Boosting Bucking 95 100 105 109 189 208 215 220 125 132 229 245 250 252 114 .08 .08 1.25 17.42 16.60 22.100 KVA 150BB2448 .60 125.29 1.92 7.46 8.29 34.46 4.00 250.00 75.25 137.25 2.50 11.96 125.83 24.33 49.67 26.29 1.150 KVA 205BB2448 .58 1.29 8.21 22.66 20.65 2.67 57.00 62.75 11.50 2.75 65.00 KVA 5BB2448 5.07 250.84 2.82 34.66 A 120 .10 229.08 275.50 33.42 4.25 5.03 83.50 9.87 2.83 14.52 87.44 208.66 125.25 10.50 83.83 12.00 165.33 29.50 62.96 12.52 4.33 9.25 3.42 2.37 10.33 A 120 .67 41.50 2.33 3 J 436 3.50 4.42 5.25 15.50 34.00 416.50 20.99 4.50 47.63 31.00 49.00 437.67 24.08 .80 34.53 45.33 51.25 2.75 2.92 7.28 131.33 15.58 83.37 208.41 31.92 12.00 82.75 38.33 D 242 .25 9.50 12.50 17.25 10.98 62.03 125.18 45.88 4.59 1.48 4. 62.71 6.65 4.Table 1 Catalog Number Insulating Transformer Rating 050BB2448 .86 6.16 137.25 42.83 13.75 33.83 8.40 45.67 31.51 41.90 4.17 .33 B 120 .52 10.36 91.67 25.05 4.83 15.50 20.65 4.30 8.42 8.08 41.00 125.77 83.33 10.40 166.75 208.33 49.42 8.50 47.38 18.00 83.04 9.67 99.75 10.20 83.79 458.39 125.25 62.88 2.50 30.25 4.58 2.38 10.17 D 222 .25 1.17 2.50 2 H 208 .84 91.05 45.22 10.33 1.83 15.33 3 E 240 .66 28.37 20.50 62.62 6.38 19.09 229.42 2.50 157.66 30.17 2.50 20.25 125.67 7.25 4.29 1.00 55.11 416.75 41.17 2 G 232 .77 22.38 2.83 12.50 66.83 3.17 2 G 227 .50 19.50 C Connection Diagram Three Phase .24 2.30 20.32 208.25 2.01 22.83 7.15 13.04 20.38 10.75 83.00 20.04 91.67 7.67 229.33 B 115 .00 416.95 2.19 10.050 KVA 100BB2448 .77 68.02 229.43 2.29 1.75 4.Wall Mounted Single Phase .88 15.83 5.77 20.08 1.17 3.07 91.03 68.67 22.50 19.75 3.33 26.33 A 208 .38 11.03 125.Buck-Boost Transformers 120 x 240 Volts Primary .00 416.87 4.72 6.08 1. .65 13.25 68.80 41.52.50 95.08 .58 4.44 12.88 10.46 5.40 20.80 125.75 19.92 14.96 6.92 5.89 41.00 63.50 20.46 9.25 16.44 12.01 4.25 2.29 1.17 D 240 1.02 4.67 47.00 41.26 20.00 87.Table 2 Catalog Number Insulating Transformer Rating 050BB2448 .96 8.83 2.39 31.56 31.25 1.17 2 G Quantity Required Connection Diagram *Output voltage for lower input voltage can be found by: 18 Rated Output Voltage —————————— Rated Input Voltage x Input Actual Voltage = Output New Voltage.150 KVA 205BB2448 .25 10.50 33.83 31.03 91.48 6.33 D 113 .58 2.61 11.73 20.13 62.52 34.67 14.67 7.29 1.00 66.75 250.56 31.50 20.44 20.00 165.00 83.50 8.33 14.25 4.51 2.750 KVA 1BB2448 1.75 22.83 7.12/24 Volts Secondary .66 16.60 11.92 13.55 4.66 189.48 2.00 166.83 27.33 94.83 12.66 3 K 208 .38 10.75 15.17 D 227 .33 62.46 9.33 20.00 175.17 10.75 31.53 137.50 9.90 2.54 137.75 36.25 2.33 45.76 11.33 208.95 4.48 6.55 13.17 166.88 4.33 4.00 318.67 208.39 34.50 KVA 2BB2448 2.00 208.60 137.83 2.00 250.50 4.63 125.83 7.46 5.17 1.17 3.35 91.50 82.10 9.67 22.33 2 G 208 1.25 8.48 6.43 6.00 KVA 5BB2448 5.65 4.250 KVA 505BB2448 .25 125.00 87.88 229.00 84.88 21.17 2 G 240 .49 2.33 28.61 68.50 4.88 41.01 41.17 .58 2.50 41.33 4.10 8.42 8.33 15.83 15.26 22.26 68.47 10.86 2.76 43.38 125.33 14.00 KVA 105BB2448 1.83 28.00 126.38 16.33 33.50 63.00 51.25 9.67 90.53 22.62 437.17 2.60 6.80 4.25 21.33 52.17 4.50 137.90 62.92 5.30 62.46 9.50 4.50 15.50 31.050 KVA 100BB2448 .00 47.75 6.66 31.00 125.42 4. 12 1.50 38.50 11.88 25.34 35.63 23.81 1.00 67.78 46.86 141.60 6.63 11.34 10.00 53.42 3.56 31.50 11.00 44.75 15.00 133.88 25.37 1.71 11.63 5.17 71.73 70.90 15.44 46.44 7.88 15.050 KVA 100BB1632 .88 22.72 1.63 8.97 33.16 93.81 5.66 2.90 16.33 62.30 3.50 15.70 6.66 6.13 62.94 7.80 14.58 46.35 3.25 5.25 2.14 4.75 51.03 125.50 33.70 25.00 78.64 187.13 3.84 7.26 31.26 10.80 22.78 15.83 177.71 66.50 10.88 7.63 3.21 35.30 D 230 .10 106.37 3.80 200.84 8.750 KVA 1BB1632 1.57 100.70 50.74 312.25 93.29 212.00 KVA 3BB1632 3.39 3.50 KVA 2BB1632 2.00 43.00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps Boosting Bucking 95 100 105 208 215 215 220 225 135 240 240 245 250 255 120 .12 1.63 312.80 37.00 30.25 5.63 11.10 D 225 .00 100.30 C 234 .150 KVA 205BB1632 .73 3.52 62.02 66.13 29.50 3 F 236 1.66 2.150 KVA 205BB1632 .25 3.10 5.63 15.61 177.00 KVA 5BB1632 5.67 13.09 1.25 3.99 31.58 312.72 3.33 11.38 9.56 .38 125.26 9.29 156.81 3.20 133.56 1.90 7.Table 4 Catalog Number Insulating Transformer Rating 050BB1632 .88 22.13 3.88 312.00 76.250 KVA 505BB1632 .25 46.93 66.56 .67 7.83 16.33 11.91 7.56 6.67 7.63 7.80 3.50 23.42 22.00 66.69 62.12 9.05 53.44 7.38 3.54 .33 11.81 23.75 51.88 25.75 156.56 1.88 93.13 2.30 16.75 3.56 66.71 4.34 2.90 9.00 27.00 54.54 1.26 31.15 354.44 312.80 30.08 2 G Quantity Required Connection Diagram *Output KVA available at reduced input voltage can be found by: Actual Input Voltage —————————— Rated Input Voltage x Output KVA = New KVA Rating.75 16.44 6.04 26.00 46.50 33.64 2.49 46.77 93.83 9.80 33.25 19. 19 .56 7.67 23.16/32 Volts Secondary .38 3.50 38.50 C 240 .39 15.74 3.60Hz .03 106.00 62.25 62.31 3.88 14.67 22.90 100.25 1.00 6.68 8.50 C 119 .10 125.00 26.72 31.96 125.16 46.44 23.33 20.50 42.100 KVA 150BB1632 .67 13.25 2.13 2.33 1.76 3.25 6.81 15.36 3.19 1.75 125.69 93.50 35.55 187.88 7.83 12.25 1.67 33.30 B 114 .00 125.90 15.38 9.60 6.55 62.11 133.50 75.59 15.63 12.13 187.09 333.56 1.25 46.85 7.52 53.77 .95 50.98 16.33 66.50 33.50 73.38 5.63 5.75 15.39 21.50 112.44 12.33 156.25 11.50 C 235 .56 14.50 50.38 1.50 2 H 208 .28 3.32 53.15 5.63 31.25 2 L 230 1.53 100.11 17.42 11.95 2 G 240 .53 26.33 2 H 234 .250 KVA 505BB1632 .30 46.66 2.25 73.12 1.30 1.94 187.00 79.No Taps .67 23.67 4.21 5.14 200.72 23.78 50.50 93.25 5.00 200.67 7.52 62.00 30.66 2.55 2.34 2.59 8.13 1.13 1.33 11.25 6.75 56.67 7.34 2.25 11.31 3.00 76.69 1.50 31.63 3.00 45.16 10.50 31.95 4.76 26.13 1.25 11.50 33.33 83.42 6.00 75.50 33.54 6.02 46.26 50.34 31.64 16.30 10.55 187.58 312.25 16.02 3.44 62.00 187.500 KVA 705BB1632 .33 2 H 240 1.67 3.Table 3 Catalog Number Insulating Transformer Rating 050BB1632 .92 50.50 22.33 79.31 187.98 62.33 20.63 7.75 46.20 9.00 22.25 2.63 15.63 9.76 16.13 .00 333.12 4.00 6.81 6.63 7.100 KVA 150BB1632 .13 156.08 53.00 138.67 200.13 1.86 15.77 1.25 125.77 3.30 3.06 9.77 93.00 KVA 105BB1632 1.10 14.02 3.67 31.25 3.17 106.19 31.40 100.73 3.38 1.38 1.33 2 H 234 1.87 133.67 13.86 33.69 4.13 2.50 100.50 37.50 22.00 132.69 1.25 19.88 15.33 3.54 14.89 46.89 46.30 36.75 31.88 14.50 6.77 6.67 40.69 10.55 2.00 93.44 3.00 21.25 50.00 333.67 15.00 200.43 133.48 3.02 3.02 3.16 9.38 3.30 46.50 22.46 6.77 31.30 C Connection Diagram Three Phase .30 C 239 .500 KVA 705BB1632 .74 3.03 93.85 7.05 10.26 31.69 2.37 1.00 55.00 77.30 C 230 .68 17.78 3.67 39.75 45.38 62.00 KVA 5BB1632 5.06 187.50 71.52 62.56 93.56 4.80 29.00 135.17 17.36 17.25 16.77 1.90 312.25 11.Buck-Boost Transformers 120 x 240 Volts Primary .98 10.78 43.62 1.33 15.00 15.06 200.88 22.12 .56 .50 A 240 .60 66.33 19.67 23.63 2.83 44.33 1.00 6.00 15.50 KVA 2BB1632 2.00 27.50 129.63 12.40 10.00 KVA 3BB1632 3.25 16.25 3.71 5.33 1.25 10.13 8.63 15.33 81.72 6.69 .50 38.33 1.67 333.67 133.44 11.88 125.00 15.19 312.80 14.67 333.63 46.50 2 H 240 .81 7.30 45.72 176.38 187.72 35.56 333.50 93.17 7.750 KVA 1BB1632 1.00 KVA 105BB1632 1.25 19.74 1.50 156.81 3.38 6.00 312.37 35.80 28.80 18.75 63.69 3.00 31.79 333.28 33.08 28.77 93.38 5.44 70.97 93.80 200.50 21.50 3 F 208 1.43 70.38 3.84 100.69 70.67 41.93 16.00 15.25 2 G 240 1.00 31.80 38.50 22.32 93.13 2.30 47.88 7.50 127.50 A 119 .00 67.13 3.50 62.44 3.85 3.30 D 244 .00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps 183Y 106 208Y 120 Boosting Bucking 195 208 225 240 245 250 256 265 272 208 1.Wall Mounted Single Phase .20 A 208 .03 125.050 KVA 100BB1632 .38 6.89 46.50 112.12 .04 133.74 6.50 6.55 6.64 106.34 46.26 10.00 62.67 4. 50 50.33 15.50 5.25 19.07 109.25 54.21 5.00 KVA 105BB1224 1.45 6.60 3.04 1.00 KVA 5BB1224 5.48 3.83 14.00 62.27 87.91 1.90 2.28 10.30 C 484 .30 C 483 1.20 C Connection Diagram Three Phase .02 11.50 125.66 2.02 20.83 14.12 4.01 95.55 65.00 47.56 5.25 .20 D 457 .75 131.08 1.40 69.77 15.97 4.97 6.15 174.83 1.76 10.64 20.60 19.30 104.33 5.17 166.73 2.40 17.12 20.67 17.63 10.84 25.70 3.30 208.93 10.08 1.20 9.20 D 457 .20 9.25 2.20 36.56 10.04 1.78 31.18 3.25 41.33 57.80 22.20 B 420 .25 83.88 23.16 17.92 18.18 100.59 2.43 5.29 1.40 218.83 20.04 .86 1.72 8.59 3.50 KVA 2BB1224 2.10 75.31 4.64 10.60Hz .09 43.77 20.50 3.50 50.17 2.43 3.75 131.96 5.64 11.44 6.87 86.74 2.25 62.47 62.69 104.40 20.32 10.40 12.24 9.80 2.60 104.20 D 473 .19 62.30 C 462 .92 10.08 2.16 5.00 100.39 90.62 85.70 10.42 6.59 31.50 38.52 17.76 1.12 62.00 68.13 2.16 180.13 31.67 29.050 KVA 100BB1224 .48 4.25 4.29 2.72 9.44 68.52 66.85 21.27 3.01 2.42 9.04 .56 15.67 66.83 172.67 28.81 10.57 79.92 15.24/48 Volts Secondary .20 36.95 6.67 29.25 99.56 62.83 14.09 31.49 1.08 83.21 2.88 24.37 5.48 1.88 25.46 5.40 87.84 23.92 34.00 104.37 5.71 41.40 104.85 1.25 49.80 28.20 30.03 62.80 24.04 1.75 455 .12 4.98 45.20 38.83 8.80 2.58 2.50 KVA 2BB1224 2.89 68.100 KVA 150BB1224 .54 41.60 17.02 10.25 41.40 16.32 33.58 3.80 27.90 31.08 2.98 68.55 8.40 114.73 3.63 5.50 165.13 65.33 59.69 82.25 68.85 34.08 2.20 33.19 9.08 10.85 3.08 1.17 41.15 87.45 62.46 7.50 41.06 45.29 2.60 462 1.44 2.250 KVA 505BB1224 .99 34.00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps 399Y 230 480Y 277 .Wall Mounted Single Phase .43 4.66 31.04 .06 20.23 11.150 KVA 205BB1224 .99 22.67 26.25 4.00 96.29 2.40 66.25 5.08 2.55 9.58 2.55 7.80 27.20 7.20 34.90 104.09 4.07 32.13 41.13 2.48 3.99 6.38 3.250 KVA 505BB1224 .00 98.50 Boosting Bucking 380 430 440 460 460 480 480 440 440 460 460 480 480 500 500 420 .40 18.14 1.76 5.50 38.26 158.04 .31 18.80 26.18 108.38 22.90 4.46 4.08 1.44 1.57 20.60 52.51 5.61 4.67 28.00 KVA 5BB1224 5.14 5.00 95.31 41.46 11.02 6.00 B 436 .00 KVA 3BB1224 3.58 83.75 31.92 15.42 4.90 15.93 32.50 47.57 21.40 218.500 KVA 705BB1224 .33 4.63 9.36 51.13 1.03 10.18 87.25 20.00 104.28 11.25 19.83 14.23 20.60 104.40 218.00 91.16 5.00 KVA Line Voltage (Available) Load Voltage (Output) Load Load Load Load Load Load Load Load Load Load Load KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps KVA Amps Boosting Bucking 230 380 416 425 430 435 440 440 450 460 277 480 480 504 277 .16 20.68 34.00 208.14 43.89 10.50 40.89 6.50 11.25 131.50 28.56 15.50 39.10 2.37 4.46 41.21 4.29 41.57 43.10 31.63 4.21 9.18 3.84 24.67 30.26 5.No Taps .38 125.00 229.68 47.28 31.08 3.93 11.Buck-Boost Transformers 240 x 480 Volts Primary .40 72.56 3.05 34.00 137.78 34.24 8.83 14.04 1.28 22.88 12.67 28.42 9.42 7.25 19.76 36.51 3.45 22.70 43.04 41.00 54.50 229.76 33.500 KVA 705BB1224 .99 2.67 15.66 2.20 C 480 1.00 8.51 2.34 31.03 22.73 5.31 3.87 2.43 4.52 5.50 4.80 104.00 114.25 86.31 62.83 13.87 3.25 17.50 62.50 83.30 20.33 57.13 45.63 8.83 15.33 60.68 49.20 34.92 16.32 5.29 1.75 1.150 KVA 205BB1224 .08 1.49 1.44 12.92 10.20 528 .30 15.19 6.40 14.86 3.77 32.67 30.32 31.85 22.42 10.75 125.75 131.67 29.50 104.17 2.75 41.50 125.08 2.20 506 .73 2.11 10.750 KVA 1BB1224 1.51 10.25 4.44 104.92 68.43 3.80 125.42 17.46 41.70 45.80 25.04 21.Table 6 Catalog Number Insulating Transformer Rating 050BB1224 .00 45.14 1.44 91.57 68.36 438 1.40 218.56 62.00 57.42 7.92 16.00 6.00 104.73 20.25 19.92 17.67 62.63 9.04 10.80 41. .56 62.97 2.84 27.50 43.60 18.050 KVA 100BB1224 .36 436 .58 3.60 504 1.75 6.42 7.01 2.50 48.70 2.20 34.25 8.04 1.75 44.00 208.40 3 E 2 G 2 G 2 H 2 G 2 H 2 G 2 H 2 G 2 H 2 H 2 G 2 H 2 G 2 G 2 H Quantity Required Connection Diagram *Output voltage for lower input voltage can be found by: 20 Rated Output Voltage —————————— Rated Input Voltage x Input Actual Voltage = Output New Voltage.95 2.96 17.20 D 472 .60 10.68 54.21 4.40 114.13 2.25 62.Table 5 Catalog Number Insulating Transformer Rating 050BB1224 .08 1.63 37.96 2.20 4.12 4.62 20.37 4.18 3.34 15.13 31.38 19.60 208.00 22.21 4.72 8.50 62.60 52.76 477 1.60 17.49 17.95 2.69 31.25 75.67 41.12 4.60 83.13 125.17 3.88 27.90 45.79 1.18 3.76 51.57 62.13 2.86 65.28 31.88 62.89 17.29 2.29 1.63 95.72 7.83 14.29 21.40 114.04 .46 10.68 51.12 3.52 10.36 418 .22 6.52 20.16 16.60 54.750 KVA 1BB1224 1.46 3.63 83.44 13.25 11.00 KVA 105BB1224 1.95 1.19 62.66 2.42 7.39 15.00 208.60 41.93 62.63 9.55 31.20 8.38 5.17 2.00 125.44 11.16 15.90 1.93 4.24 31.19 5.40 13.83 33.14 1.50 49.40 11.32 34.33 83.00 17.76 457 1.80 91.60 D 456 1.56 45.52 20.03 20.38 20.80 25.05 2.04 41.00 11.85 20.16 4.17 4.60 45.00 104.44 12.08 .14 1.20 400 .83 31.14 15.55 8.57 22.78 5.60 483 1.71 65.50 .41 6.08 2.92 14.29 2.08 3.50 1.40 12.13 2.25 19.00 28.15 1.32 36.76 31.70 137.07 41.04 1.08 20.60 15.88 5.75 5.25 19.98 2.44 5.27 15.16 18.83 29.50 11.50 125.53 31.73 2.43 4.80 50.29 2.52 63.14 6.50 1.08 1.100 KVA 150BB1224 .86 10.86 6.50 34.75 25.25 20.50 473 .62 69.08 1.82 2.52 72.11 181.20 8.21 4.20 D 467 .00 114.08 3.20 208.44 31.86 1.58 2.76 34.20 208.76 419 1.50 110.83 15.00 2.38 10.97 31.76 5.82 2.00 KVA 3BB1224 3.60 49.77 103.04 41.85 32.01 4.30 C 230 .88 5. X4 X3 X2 X1 21 . NOTES • Inputs and Outputs may be reversed: KVA capacity remains constant. • Refer to NEC 450-4 for overcurrent protection of an autotransformer. All applications are suitable for 60Hz only.Buck-Boost Connection Diagrams Single Phase Diagram A HIGH VOLTAGE H4 H3 Three Phase Diagram E Œ LOW VOLTAGE NEUTRAL X2 H1 X4 X3 X1 X1 X2 X3 X4 H1 H2 H2 H1 H4 H4 H4 X2 X3 X4 X1 Diagram F Œ Diagram G LOW VOLTAGE 1 2 3 H4 H4 X2 X1 LOW VOLTAGE NEUTRAL X1 X2 H2 X3 X4 H1 H2 H2 H1 H4 H3 H3 H4 H4 X3 H3 X4 H2 H1 X4 X3 H2 H1 X4 X3 X2 X1 X1 1 2 HIGH VOLTAGE 3 OPEN DELTA X1 X2 H2 H1 X4 X3 X2 H3 LOW VOLTAGE H3 H3 H3 H3 H2 H1 X4 Diagram B LOW VOLTAGE H3 H4 H2 H1 X4 X3 X2 X1 X3 X2 X1 HIGH VOLTAGE WYE HIGH VOLTAGE WYE HIGH VOLTAGE Diagram J Œ LOW VOLTAGE Diagram H LOW VOLTAGE 3 2 1 H4 H4 X2 X3 X4 H3 H3 H2 H1 X4 X3 X2 H1 X1 Diagram C X1 HIGH VOLTAGE X2 H4 H3 H2 H1 X4 X3 X1 X2 X3 X4 H1 H2 NEUTRAL H3 H4 H3 H4 H4 H2 H2 H1 X4 LOW VOLTAGE H3 H2 H1 X4 X3 X2 X3 X2 X1 X1 3 2 HIGH VOLTAGE X1 Diagram D LOW VOLTAGE HIGH VOLTAGE WYE 1 OPEN DELTA H4 H3 H2 H1 X4 X3 X2 X1 Diagram K Œ LOW VOLTAGE NEUTRAL Diagram L 1 HIGH VOLTAGE 2 3 X4 X4 HIGH VOLTAGE X1 X2 X2 X1 X3 X4 H1 H1 H2 H2 H3 H4 H3 H4 H4 X3 X4 X3 X2 X1 H1 X1 H1 H2 H2 X3 X2 Diagram #1 (Standard Step-down application) H1 H2 H3 H4 X3 H3 H2 H1 X4 X2 X1 1 H3 H4 2 H4 H3 3 HIGH VOLTAGE WYE LOW VOLTAGE OPEN DELTA Œ The neutral XO should not be used when the source is a three wire supply. 0 KVA). 5. This period of secondary voltage instability. A transformer in a circuit subject to inrush will typically attempt to provide the load with the required current during the inrush period. Factory-mounted for integral fusing on the secondary side to save panel space.5. This period of high current demand. The transformer must therefore by designed and constructed to accommodate the high inrush current. Two jumpers links are standard with all transformers which can be jumpered. while maintaining secondary voltage stability. dirt and industrial contaminants for maximum protection in hostile and industrial environments. Fuse clips (most models). referred to as inrush. Molded into the transformer and virtually impossible to break during wiring. Integrally-molded barriers. 3. IL and CSA. and can last up to 40 milliseconds. Epoxy-encapsulated (50-750 VA) epoxy resin impregnated (1. According to NEMA standards. it will be at the expense of the secondary voltage stability by allowing the voltage to the load to decrease as the current increases. the secondary voltage should typically be at 85% of the rated voltage. ANSI. save wiring time and save the space. 22 . Extra-deep barriers reduce the chance of shorts from frayed leads or careless wiring. Industrial Control Circuit Transformers are specifically designed and built to provide adequate voltage to the load while accommodating the high current levels present at inrush. can be of such a magnitude that the transformer is unable to supply sufficient voltage to energize the load. Up to 30% greater terminal contact area permits low-loss connections. may be as great as ten times the current required under steady state (normal) operating conditions. Terminals. 2.Industrial Control Circuit Transformer Features 1. Completely seals the transformer coils against moisture. dust. These transformers deliver excellent secondary voltage regulation and meet or exceed the standards established by NEMA.0 . save wiring time and save the cost of buying an add-on fuse block. Ten year warranty At no additional cost. Jumpers supplied. 4. However. 6. Operation Industrial control circuits and motor control loads typically require more current when they are initially energized than under normal operating conditions. Between terminals and between terminals and transformer protect against electrical creepage.Their hearty construction and excellent electrical characteristics provide reliable operation of electromagnetic devices and troublefree performance. resulting from increased inrush current. A full quarter-inch of thread on the 10-32 terminal screws pre vents stripping and pullout. Secondary Voltage is the voltage required for load operation which is connected to the transformer load voltage terminals. read down until a value equal to or greater than the Application Inrush VA is found. If the primary voltage carries between 5% and 10% of nominal. the 90% secondary voltage column should be used. transformer selection is a simple 5-step process as follows: 1. Read left to the Transformer VA Rating column to determine the proper transformer for this application. relays. the 95% secondary voltage column should be used. If not. As a final check. timers. Sealed VA is also referred to as steady state VA. solenoids. After determining the proper secondary voltage column. Regulation Chart Transformer VA Rating 25 50 75 100 150 200 250 300 500 750 1000 1500 2000 3000 5000 95% Secondary Voltage 100 170 310 370 780 810 1400 1900 4000 8300 9000 10500 17000 24000 55000 Inrush VA at 20% Power Factor 90% 85% Secondary Voltage Secondary Voltage 130 150 200 240 410 540 540 730 930 1150 1150 1450 1900 2300 2700 3850 5300 7000 11000 14000 13000 18500 15000 20500 25500 34000 36000 47500 92500 115000 To comply with NEMA standards which require all magnetic devices to operate successfully at 85% of rated voltage. which will be energized together. In no case should a figure less than the Application Inrush VA be used. 3. pilot lights. which is connected to the transformer supply voltage terminals. etc. select a transformer with a VA rating equal to or greater than the total sealed VA. It is calculated by adding the inrush VA requirements of all devices (contactors. the 90% secondary voltage column is most often used in selecting a transformer. 23 . Sealed VA is the product of load voltage (V) multiplied by the current (A) that is required to operate the circuit after initial start-up or under normal operating conditions. and primary and secondary voltage requirements. Once the circuit variables have been determined.). 5. Refer to the following pages to determine the proper catalog number based on the transformer VA. Determine the Application Inrush VA by using the following industry accepted formula: Application Inrush VA = (Inrush VA)2 + (Sealed VA)2 2. It is calculated by adding the sealed VA requirements of all electrical components of the circuit that will be energized at any given time.Selection Process Selecting a transformer for industrial control circuit applications requires knowledge of the following terms: Inrush VA is the product of load voltage (V) multiplied by the current (A) that is required during circuit start-up. Primary Voltage is the voltage available from the electrical distribution system and its operational frequency. 4. If the primary voltage is basically stable and does not vary by more than 5% from nominal. Refer to the Regulation Chart. make sure that the Transformer VA Rating is equal to or greater then the total sealed requirements. Inrush VA requirements are best obtained from the component manufacturer. Sealed VA requirements are best obtained from the component manufacturer. Primary Volts 240x 480 Catalog Number MT0050B MT0075B MT0100B MT0150B MT0200B MT0250B MT0300B MT0350B MT0500B VA Rating 50 75 100 150 200 250 300 350 500 Temp.5 4.8 ⁹⁄₃₂ x ¹³⁄₃₂ 30.1 ⁹⁄₃₂ x ¹³⁄₃₂ 29.25 8. • Insulation materials are of the highest rating available for the temperature class.30 1.0 ⁷⁄₁₆ x ³⁄₄ 89.65 0. • Attractive black finish: easy-to-read nameplate with complete rating data and wiring diagram.0 ⁷⁄₁₆ x ³⁄₄ 53.Specifications • Laminations are of the finest silicon steel to minimize core losses and to increase optimum performance and efficiency. 24 .7 ¹³⁄₆₄ x ³⁄₈ 8.4 13.50 14.87 1.61 3. (lbs) ¹³⁄₆₄ x ³⁄₈ 2.08 3.2 ¹³⁄₆₄ x ³⁄₈ 6.43 0.6 ⁵⁄₁₆ x ¹¹⁄₁₆ 19. Slotted mounting feet permit easy installation.5 H1 H1 H3 H2 H4 H3 H1 H2 H3 H2 H4 H4 24V X2 X1 Includes secondary fuse clip on sizes 50 through 500VA.13 4.48 Secondary Volts 120/115/110 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ¹⁄₂ 7 7 ⁷⁄₈ 6 ³⁄₄ 7 7 ¹⁄₂ 7 ³⁄₄ “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ 5 ¹⁄₄ 6 ³⁄₄ 6 ³⁄₄ 9 9 “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ 4 ⁷⁄₁₆ 5 ¹¹⁄₁₆ 5 ¹¹⁄₁₆ 7 ⁹⁄₁₆ 7 ⁹⁄₁₆ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₄ 5 ³⁄₄ 5 ¹⁄₂ 3 ⁹⁄₁₆ 4 ⁷⁄₁₆ 4 ¹⁄₈ 6 “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 4 ³⁄₈ 6 ¹⁄₁₆ 6 ¹⁄₁₆ 6 ¹⁄₂ 6 ¹⁄₂ 50/60Hz 240V 230V 220V 480V 460V 440V Mounting Approx.4 17. • Two jumper lines are standard with all transformers which can be jumpered. Slots Wt.1 11. • UL listed and CSA certified. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C Output Ampere 2.5 ¹³⁄₆₄ x ³⁄₈ 10. • Factory mounted type “K” fuse clips are standard on all single secondary transformers.7 3. (lbs) ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ⁵⁄₁₆ x ¹¹⁄₁₆ 2. 230 x 460.5 ¹³⁄₆₄ x ³⁄₈ 4.04 17.0 ⁹⁄₃₂ x ¹³⁄₃₂ 38.7 8. • Copper magnet wire of the highest quality assures efficient operation.09 43.17 2.3 ¹³⁄₆₄ x ³⁄₈ 13.83 Secondary Volts 24 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ³⁄₈ “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₈ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 50/60Hz 240V 480V Mounting Approx.6 ¹³⁄₆₄ x ³⁄₈ 3.0 H1 H1 H3 H2 H4 H3 H1 H2 H3 H2 H4 H4 X2 110V 115V 120V X1 Includes secondary fuse clip on sizes 50 through 750VA. • 50/60 Hz rated.17 6. • Optional type “M” fuse clips available for separate mounting. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 115°C 115°C 115°C 115°C 115°C Output Ampere 0. B E C D A Top View Side View Primary Volts 240x 480.70 13.42 12.35 6.5 10.39 26.04 4.2 ⁵⁄₁₆ x ¹¹⁄₁₆ 28.52 8.58 20. • Mounting brackets are heavy gauge steel to add strength to core construction and provide stable mounting.74 2. Slots Wt.0 ¹³⁄₆₄ x ³⁄₈ 11. 220 x 240 Catalog Number MT0050A MT0075A MT0100A MT0150A MT0200A MT0250A MT0300A MT0350A MT0500A MT0750A MT1000A MT1500A MT2000A MT3000A MT5000A VA Rating 50 75 100 150 200 250 300 350 500 750 1000 1500 2000 3000 5000 Temp.2 6.33 10. Slots Wt.43 0.25 Secondary Volts 120 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ³⁄₈ 7 “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₈ 5 ³⁄₄ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 50/60Hz H1 H2 H3 Mounting Approx.4 19.35 6.3 6.33 10.6 3.5 6.50 2.42 12.4 13.08 3. (lbs) ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ⁵⁄₁₆ x ¹¹⁄₁₆ ⁵⁄₁₆ x ¹¹⁄₁₆ 2.2 19. (lbs) ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ⁵⁄₁₆ x ¹¹⁄₁₆ ⁵⁄₁₆ x ¹¹⁄₁₆ 2.7 3.17 6.7 277V 208V 120V X2 X1 Includes secondary fuse clip on sizes 50 through 750VA.08 2.08 3. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C Output Ampere 0. Slots Wt. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C Output Ampere 2.17 6. (lbs) ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ⁵⁄₁₆ x ¹¹⁄₁₆ 2.1 11.17 6.13 4. Slots Wt.0 11.83 Secondary Volts 24 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ¹⁄₂ “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 19 ¹⁄₅ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₄ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 50/60Hz 115V 230V Mounting Approx.6 16. Primary Volts 115x 230 Catalog Number MT0050D MT0075D MT0100D MT0150D MT0200D MT0250D MT0300D MT0350D MT0500D VA Rating 50 75 100 150 200 250 300 350 500 Temp.17 2.25 8.7 X2 110V 115V 120V X1 Includes secondary fuse clip on sizes 50 through 750VA.50 14.2 11.65 0.7 8.58 20.42 0. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C Output Ampere 0.1 11.7 17.7 10.83 1. Slots Wt. 0V 25 .6 4. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C Output Ampere 2.32 Secondary Volts 110/115/120 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ³⁄₈ 7 “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₄ 5 ³⁄₄ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 50/60Hz H1 600V 575V 540V H2 Mounting Approx.9 8.25 1.6 4.61 3.87 1.92 4.63 0.3 10.42 12.8 8.8 4.50 14.7 4.58 20.8 25.2 H1 H1 H3 H2 H4 H3 H1 H2 H3 H2 H4 H4 24V X2 X1 Includes secondary fuse clip on sizes 50 through 500VA.2 H1 H1 H3 H2 H4 H3 H1 H2 H3 H2 H4 H4 24V X2 X1 Includes secondary fuse clip on sizes 50 through 500VA.2 25.2 6.4 13.74 2.2 13.13 4. Primary Volts 208/277 Catalog Number MT0050F MT0075F MT0100F MT0150F MT0200F MT0250F MT0300F MT0350F MT0500F MT0750F VA Rating 50 75 100 150 200 250 300 350 500 750 Temp.4 10.Primary Volts 120x 240 Catalog Number MT0050C MT0075C MT0100C MT0150C MT0200C MT0250C MT0300C MT0350C MT0500C VA Rating 50 75 100 150 200 250 300 350 500 Temp.04 4.7 3.67 2.30 1.83 Secondary Volts 24 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ³⁄₈ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ¹⁄₂ “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 19 ¹⁄₅ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ³⁄₈ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₄ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 50/60Hz 120V 240V Mounting Approx.4 6.8 8.33 10.3 13.9 3. (lbs) ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ¹³⁄₆₄ x ³⁄₈ ⁵⁄₁₆ x ¹¹⁄₁₆ 2.25 8.5 10. Primary Volts 540/575/600 Catalog Number MT0050E MT0075E MT0100E MT0150E MT0200E MT0250E MT0300E MT0350E MT0500E MT0750E VA Rating 50 75 100 150 200 250 300 350 500 750 Temp. 30 200 55°C 8.17 4 ³⁄₄ 3.5 ¹³⁄₆₄ x ³⁄₈ 4.7 ¹³⁄₆₄ x ³⁄₈ 9.Specifications Primary Volts 208/230/460 Catalog VA Number Rating MT0050G 50 MT0075G 75 MT0100G 100 MT0150G 150 MT0200G 200 MT0250G 250 MT0300G 300 MT0350G 350 MT0500G 500 MT0750G 750 MT1000G 1000 MT1500G 1500 MT2000G 2000 MT3000G 3000 MT5000G 5000 Secondary Volts 115 Dimensions (inches) Temp.58/3.91/.04 500 55°C 20.7 ⁷⁄₁₆ x ³⁄₄ 102.85 200 55°C 1. Primary Volts 380/400/415 Catalog Number MT0050I MT0075I MT0100I MT0150I MT0200I MT0250I MT0300I MT0350I MT0500I MT0750I 110/220V VA Temp.4 ¹³⁄₆₄ x ³⁄₈ 4.227 75 55°C . (lbs) ¹³⁄₆₄ x ³⁄₈ 3.0 ¹³⁄₆₄ x ³⁄₈ 8.2 ¹³⁄₆₄ x ³⁄₈ 11.5 ¹³⁄₆₄ x ³⁄₈ 6.0 ¹³⁄₆₄ x ³⁄₈ 4.72/1.5 ⁷⁄₁₆ x ³⁄₄ 63.39 7 ⁹⁄₁₆ 31.74 4 ¹⁄₄ 55°C 2.4 230V X3 X2 Includes secondary fuse clip on sizes 50 through 500VA. Slots Wt.51/1.53/8.35 Secondary Volts 24/115 Dimensions (inches) “A” 3 ¹⁄₄ 3 ¹⁄₂ 3 ⁵⁄₈ 4 ³⁄₈ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₈ 5 ³⁄₈ 6 ¹⁄₂ “B” 3 3 ³⁄₈ 3 ³⁄₄ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ 5 ¹⁄₄ “C” 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ 4 ³⁄₄ “D” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹⁄₂ 3 ¹⁄₄ 3 3 ³⁄₄ 3 ⁷⁄₈ 4 ¹⁄₈ 5 ¹⁄₄ “E” 2 ¹⁄₄ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 4 ³⁄₈ 50/60Hz H1 H2 460V Mounting Approx.2 ¹³⁄₆₄ x ³⁄₈ 7.35 5 ⁷⁄₈ 7.50/2.5 ⁹⁄₃₂ x ⁹⁄₁₆ 42.6 ¹³⁄₆₄ x ³⁄₈ 15.79/.11/1.91 250 55°C 2.09 8 115°C 43.7 ⁷⁄₁₆ x ³⁄₄ 102.41 Secondary Volts 110/220 Dimensions (inches) “A” 3 3 ¹⁄₂ 3 ⁹⁄₁₆ 4 4 4 ³⁄₈ 4 ³⁄₄ 5 ¹⁄₄ 5 ³⁄₈ 7 “B” 3 3 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ “C” 2 ⁹⁄₁₆ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ “D” 2 2 ¹⁄₂ 2 ⁹⁄₁₆ 2 ⁷⁄₈ 2 ¹⁄₂ 2 ⁷⁄₈ 3 ¹⁄₄ 3 ³⁄₄ 4 ¹⁄₈ 5 ³⁄₄ “E” 2 ¹⁄₂ 2 ¹⁄₂ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 50/60Hz H1 415V H2 400V Mounting Approx.04 7 ¹⁄₂ 115°C 17.18/1.48 10 ¹⁄₂ “B” 3 3 ³⁄₈ 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ 6 ³⁄₈ 6 ³⁄₄ 6 ³⁄₄ 9 9 “C” 2 ⁹⁄₁₆ 2 ⁷⁄₈ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ 5 ³⁄₈ 5 ¹¹⁄₁₆ 5 ¹¹⁄₁₆ 7 ⁹⁄₁₆ 10 ³⁄₁₆ “D” 2 ¹⁄₈ 2 ³⁄₈ 2 ¹¹⁄₁₆ 3 ¹⁄₁₆ 2 ³⁄₄ 3 ¹⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₄ 5 ³⁄₄ 4 ¹⁄₂ 4 ⁷⁄₁₆ 5 ¹⁄₄ 4 ⁵⁄₈ 6 ¹⁄₂ “E” 2 ¹⁄₂ 2 ¹³⁄₁₆ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 5 ⁵⁄₁₆ 6 ¹⁄₁₆ 6 ¹⁄₁₆ 6 ¹⁄₂ 6 ¹⁄₂ 50/60Hz Mounting Approx. (lbs) ¹³⁄₆₄ x ³⁄₈ 3.17 4 ³⁄₄ 55°C 2.9 ⁵⁄₁₆ x ¹¹⁄₁₆ 15.5 ⁷⁄₁₆ x ³⁄₄ 63.84/4.1 ¹³⁄₆₄ x ³⁄₈ 13.52 7 10.65 3 ³⁄₈ 55°C 0.68/.4 ¹³⁄₆₄ x ³⁄₈ 11.17/.05/.08/.33/1.55/2.13/.34 100 55°C .30 4 ¹⁄₄ 2. Output Rating Rise Amperes 50 55°C 2.05/17.04 5 5.0 X4 X4 X2 X3 110V Does not include secondary fuse clip.65 100 55°C 4.89/6.58/26.0 H1 H2 H3 575V 460V 230V X3 X2 115V X1 H3 380V H4 X3 X1 X4 X2 X3 0V X1 X1 220V H4 115V X1 0V H3 208V Does not include secondary fuse clip.7 ¹³⁄₆₄ x ³⁄₈ 10.39 8 ¹⁄₄ 115°C 26.0 ¹³⁄₆₄ x ³⁄₈ 13.79/13.2 ⁹⁄₃₂ x ⁹⁄₁₆ 33.0 ⁵⁄₁₆ x ¹¹⁄₁₆ 20.5 ⁷⁄₁₆ x ³⁄₄ 42.37/6.53/.14 300 55°C 2.2 ⁹⁄₃₂ x ⁹⁄₁₆ 33.42/2.63/2.455 150 55°C 1.0 ¹³⁄₆₄ x ³⁄₈ 9. Rise 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 55°C 115°C 115°C 115°C 115°C 115°C Secondary Volts 95/115 Dimensions (inches) “B” 3 3 ³⁄₈ 3 ³⁄₈ 3 ³⁄₄ 4 ¹⁄₂ 4 ¹⁄₂ 4 ¹⁄₂ 5 ¹⁄₄ 5 ¹⁄₄ 5 ¹⁄₄ 6 ³⁄₈ 6 ³⁄₄ 9 9 9 “C” 2 ⁹⁄₁₆ 2 ⁷⁄₈ 2 ⁷⁄₈ 3 ³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 3 ¹³⁄₁₆ 4 ³⁄₄ 4 ³⁄₄ 4 ³⁄₄ 5 ³⁄₈ 5 ¹¹⁄₁₆ 7 ⁹⁄₁₆ 7 ⁹⁄₁₆ 10 ¹³⁄₁₆ “D” 2 ³⁄₁₆ 2 ³⁄₈ 2 ⁷⁄₈ 3 ¹⁄₄ 2 ³⁄₄ 3 ³⁄₁₆ 3 ⁵⁄₈ 3 ³⁄₄ 4 ⁵⁄₈ 5 ³⁄₄ 4 ¹⁄₂ 5 ¹⁄₄ 4 ³⁄₁₆ 5 ¹⁄₄ 8 ¹⁄₄ “E” 2 ¹⁄₂ 2 ¹³⁄₁₆ 2 ¹³⁄₁₆ 3 ¹⁄₈ 3 ³⁄₄ 3 ³⁄₄ 3 ³⁄₄ 4 ³⁄₈ 4 ³⁄₈ 4 ³⁄₈ 5 ⁵⁄₁₆ 6 ¹⁄₁₆ 6 ¹⁄₂ 6 ¹⁄₂ 6 ¹⁄₂ 50/60Hz 95/115 Output Amperes “A” .455/.82/3.0 ⁵⁄₁₆ x ¹¹⁄₁₆ 30.4 ¹³⁄₆₄ x ³⁄₈ 9.36 350 55°C 3. Primary Volts 230/460/575 Catalog VA Number Rating MT0050H 50 MT0075H 75 MT0100H 100 MT0150H 150 MT0200H 200 MT0250H 250 MT0300H 300 MT0350H 350 MT0500H 500 MT0750H 750 MT1000H 1000 MT1500H 1500 MT2000H 2000 MT3000H 3000 MT5000H 5000 Temp. (lbs) ¹³⁄₆₄ x ³⁄₈ 3.58/1.7 ¹³⁄₆₄ x ³⁄₈ 11.70 7 ¹⁄₈ 115°C 13.87 150 55°C 6.87 3 ⁷⁄₈ 1.52 7 ³⁄₈ 115°C 8.28/1.68/3. Primary Volts 208/230/460 Catalog Number MT0050J MT0075J MT0100J MT0150J MT0200J MT0250J MT0300J MT0350J MT0500J 24/115V VA Temp.9 ¹³⁄₆₄ x ³⁄₈ 7.7 ⁵⁄₁₆ x ¹¹⁄₁₆ 16.74 4 ¹⁄₄ 2.82/.35 6 55°C 6.61 5 ¹⁄₈ 3.3 ¹³⁄₆₄ x ³⁄₈ 4.63/43.04 5 ⁷⁄₈ 55°C 4.8 ¹³⁄₆₄ x ³⁄₈ 4.48 13 ¹⁄₂ Mounting Approx.0 H1 H2 H3 H4 460V 230V 208V 115V X2 X1 Includes secondary fuse clip on sizes 50 through 750VA.5 ⁵⁄₁₆ x ¹¹⁄₁₆ 16.87 3 ¹¹⁄₁₆ 55°C 1.8 ⁵⁄₁₆ x ¹¹⁄₁₆ 23.6 ⁵⁄₁₆ x ¹¹⁄₁₆ 21.8 ¹³⁄₆₄ x ³⁄₈ 5.26/4.74 250 55°C 10.6 ¹³⁄₆₄ x ³⁄₈ 13.70 7 ¹⁄₈ 15. Output Rating Rise Amperes 50 55°C .0 ¹³⁄₆₄ x ³⁄₈ 5. Output Rise Amperes “A” 55°C 0. 26 24V 0V 95V 0V X2 0V 0V H4 . Slots Wt.0 ¹³⁄₆₄ x ³⁄₈ 7. Slots Wt.9 ¹³⁄₆₄ x ³⁄₈ 10. (lbs) ¹³⁄₆₄ x ³⁄₈ 2.5 ⁵⁄₁₆ x ¹¹⁄₁₆ 28.5 ⁵⁄₁₆ x ¹¹⁄₁₆ 21.0 ⁵⁄₁₆ x ¹¹⁄₁₆ 29.16/2.44 75 55°C 3.0 ⁵⁄₁₆ x ¹¹⁄₁₆ 28. Slots Wt.09 8 ⁵⁄₈ 52.61 5 ¹⁄₄ 55°C 3.04 8 ¹⁄₄ 21.17 300 55°C 12.27 750 55°C 6.43 3 ¹⁄₈ 55°C 0.65 3 ³⁄₈ 1.9 ¹³⁄₆₄ x ³⁄₈ 7.61 350 55°C 14.0 ⁵⁄₁₆ x ¹¹⁄₁₆ 29.59 500 55°C 4.30 4 ³⁄₁₆ 55°C 1.44 3 . Transformers are designed for 30°C average ambient temperature with a 40° C maximum during any 24 hour period. Ampere A unit of electric current flow. as in electrical noise attenuation. Also referred to as dual voltage or series multiple winding. at rated voltage and frequency. Dielectric Tests A series of tests conducted to verify effectiveness of insulation materials and clearances used between turns and layers in the winding. Distribution Transformer Generally referred to as any transformer rated 500 KVA and below.20%.– a recognized organization which specifies the standards for transformers. BIL Basic Impulse Level measures the ability of the insulation system to withstand high voltage surges. Copper Loss See load loss. without exceeding its designed temperature rise. See Terminal Chamber. Also referred to as excitation loss or no-load loss. Inc. ATC Air Terminal Chamber. Ambient Temperature The inherent or existing temperature of surrounding atmosphere into which the heat of a transformer is dissipated. Compensated Transformer A transformer with a turns ratio which provides a higher than rated voltage at no load and rated voltage at rated load. ASTM American Society for Testing Materials. Dry Type A transformer without liquid for cooling. Buck-Boost Small KVA. Delta A standard three phase connection with the ends of each phase winding connected in series to form a loop with each phase 120 degrees from each other. ANSI American National Standards Institute. Common Mode Electrical noise or voltage disturbance that occurs between one of the line leads and the common ground. Banked Two or more single phase transformers connected together to supply a three phase load. Dual Winding A winding consisting of two separate parts which can be connected in series or in parallel. Also referred to as load loss or winding loss. potential. Center Tap A reduced capacity tap at the midpoint in a winding. or other specialty transformers. Term is abbreviated with the ANSI designation AA indicating open. two-winding transformers typically wired as an autotransformer to raise or lower single and three phase line voltages by 10 . Continuous Rating The constant load which a transformer can maintain indefinitely. Cast Coil Transformer Transformer with coils solidly case in epoxy resin under vacuum in a mold. Also called cast resin or epoxy cast coil transformer. Conductor Losses Losses in watts caused by the resistance of the transformer winding during a loaded condition. Decibel (dB) A standard unit of measure of intensity. or between the ground plane and either the line or the neutral. Control Transformer A transformer designed to provide good voltage regulation for control or instrumentation circuits having high inrush current or low power factor conditions. Attenuation A term used to denote a decrease in magnitude in transmission from one point to another. Autotransformer A transformer with one winding per phase in which part of the winding is common to both the primary and the secondary circuits. Core Loss Losses in watts caused by magnetization of the core and its resistance to magnetic flux when excited or energized at rated voltage and frequency. Certified Test Actual values taken during production testing which certify the values or results or testing to apply to a specific unit.Glossary Air Cooled A transformer which uses air as the cooling method medium. Ambient Noise Level The inherent or existing noise level of the surrounding area measured in decibels. Coil Turns of electrical grade wire or strip conductor material wound on a form. Also referred to as 3-wire. Current Transformer Transformer generally used in control or instrumentation circuits for measuring current. Typically expressed as a ratio or in decibels. often referred to as winding. Such transformers cannot be used for reverse feed. except for current. Delta-Wye A term or symbol indicating the primary connected in delta and the secondary in wye when pertaining to a three phase transformer or transformer bank. 27 . Also referred to as lighting tap. Core Electrical grade steel laminations which carries the magnetic flux. natural draft ventilated construction. KVA Kilovolt ampere rating with designates the capacity or output with a transformer can deliver at rated voltage and frequency without exceeding designed temperature rise. Impulse Tests Dielectric test which determines BIL capability by applying high frequency. Grounding Transformer A special 3 phase autotransformer used to establish a stable neutral point on a 3-wire delta system. Usually expressed in percent of the rated current of a winding in which it is measured. which isolate the primary circuit from the secondary circuit. Also referred to as Hertz. or complete cycles. Voltage drop due to conductor resistance at rated current expressed in percent of rated voltage IX% Percent reactance. Inrush Current Abnormally high current. as in 60 cycles per second. (1 KVA = 1000VA. Full Capacity Tap Tap than can deliver rated KVA without exceeding its designated temperature rise. Term is abbreviated with the ANSI designation OA indicating natural oil ambient ventilation. Voltage drop due to impedance at rated current expressed in percent of rated voltage. 28 . Liquid Transformer A transformer which used mineral oil. Power Factor The relation of watts to volt amps in a circuit. NEC National Electric Code. H2. Also referred to as Zig-Zag transformer. Impedance Retarding or opposing forces of current flow in AC circuit. typically designated as single phase 2-wire or 3-wire. or other dielectric fluid. Load Losses Losses in watts which are the result of current flowing to the load. Insulating Transformer One which the primary winding connected to the input or source. NEMA National Electrical Manufacturers Association. designated as HV on the nameplate and as H1. or 1000 volt amperes). steep wave-front voltage between windings and ground. Parallel Operation Transformers having compatible design features with their appropriate terminals connected together. or three phase 3-wire or 4-wire. is insulated from the secondary winding connected to the output or load. IZ% Percent impedance. Potential Transformer A transformer generally used in instrumentation circuits for measuring or controlling voltage. High Voltage Winding Designates the winding with the greater voltage. Lamination Thin sheets of special steel used to make the core of a transformer. Polarity Designates the instantaneous direction of the voltages in the primary compared to the secondary.Electrostatic Shield Conductor material placed between the primary and secondary windings which is grounded to reduce electrical noise or line interference. copper loss. Also referred to as winding loss. Also referred to as two-winding or isolation transformers. or conductor loss. Grounding Connecting one side of a circuit to earth. FCAN “Full Capacity Above Normal. that polarity alternates from positive to negative per unit of time. Exciting Current “No-load current” flowing in the winding used to excite the transformer when all other windings are open-circuited. Encapsulated Transformer with coils either encased or cast in an epoxy resin or other encapsulating materials.” A designation for no-load taps indicating the taps are suitable for full-rated KVA at the designated voltages above nominal voltage. which serves as an insulating and cooling medium. caused by residual flux in the core. or creating a conducting path to some conducting body that serves in place of earth through low-resistance or low-impedance paths. Hertz (Hz) A term for AC frequency in cycles per second. Hi Pot High potential dielectric test impressed on the windings to check insulation materials and clearances. usually in the secondary winding. on the termination. Frequency Designates the number of times. Voltage drop due to reactance at rated current expressed in percent of rated voltage. Also referred to a Center tap. No-load Loss See core loss. which is occasionally drawn when a transformer is energized. Oil Cooled A transformer which uses oil as the cooling medium. Iron Loss See No Load Loss or Core loss. Fan Cooled Cooled mechanically to maintain rated temperature rise. Flexible Connection A non-rigid connection used to eliminate transmission of noise and vibration. Mid-tap A reduced capacity tap midway in a winding. FCBN Same as above except Full Capacity Below Normal. Phase Classification of an AC circuit. typically using auxiliary fans to accelerate heat dissipation. etc. Inductance A property which opposes a change in current flow. IR% Percent resistance. Induced Potential Test A high frequency dielectric test which verifies the integrity of insulating materials and electrical clearances between turns and layers of a winding. expressed in percentage. 29 . Sealed Transformer An enclosed transformer completely sealed from the outside environment and usually contains pressurized inert gas. Ratio Refers to the turns ratio or the voltage ratio between the primary and secondary winding. Regulation The percent change in secondary output voltage when the load changes from full load to no-load at a given power factor. Transformer Tests Normal. or supply side connected to the primary of the transformer in a circuit. usually to reduce or control current. Wye Connection A three phase connection with similar ends of each phase connected together at a common point which forms the electrical neutral point which is typically grounded. Series/Multiple A winding consisting of two or more sections which can be connected for series operation or multiple (parallel) operation. or from spurious signals across the metallic hot line and the neutral conductor. (5) Induced – double induced two time normal voltage. Regulation may be expressed in percent (per unit) on the basis or rated secondary voltage at full load. See also grounding transformers. UL Underwriters Laboratories. capacity. (3) Impedance. Star Connection Same as wye connection. Optional special tests include: (a) Heat Run – temperature testing. (2) load loss – winding or copper loss. typically used when the transformer is not direct connected or close coupled to another device. Step-down Transformer One in which the energy transfer is from the high voltage winding (primary input circuit) to the low voltage winding (secondary output or load circuit). Tap A connection brought out of winding at some point between its extremities to permit changing the nominal voltage ratio. Zig-Zag Special transformer connection commonly used with grounding transformers. Step-up Transformer The energy transfer is from the low voltage winding to the high voltage winding. typically measured as either average rise by resistance or as hot-spot. (4) Hi-pot – high voltage between windings and ground. T-connection Use of Scott connection for three phase operation using two primary (main) and two secondary (teaser) coils. frequency. Winding Losses See Load Losses. Temperature Rise The increase over ambient temperature of the winding due to energizing and loading the transformer. temperature rise. Terminal Chamber An enclosure with space for making connection to a substation transformer.Primary Rating The input. thus reducing available power because of lower output voltage. KVA. or vice versa. Scott Connection A transformer connection generally used to get a two phase output from the secondary of a three phase input. with the low voltage winding connected to the power source (primary input circuit) and the high voltage connected to the load (secondary output circuit). Reactance The effect of inductive and capacitive components of a AC circuit producing other than unity power factor. Voltage Regulation The change in secondary voltage which occurs when the load is reduced from rated value to zero. typically expressed as FCAN and FCBN for no-load operation. Secondary Rating The output. Total Losses The transformer electrical losses which include no-load losses (core loss) and load losses (winding losses). Transverse Mode Electrical noise or voltage disturbance that occurs between phase and neutral. Rating The design characteristics. etc. (b) Noise tests – sound level measurement (c) Impulse tests – BIL tests. routing production tests include: (1) core loss (excitation loss or non-load loss). Taps are usually located in the high voltage winding. such as primary and secondary voltage. with the values of all other qualities remaining unchanged. Also referred to as dual voltage or series-parallel. Reduced Capacity Taps Taps which are rated for winding current only (versus rated KVA). source. Reactor A single winding device with an air or iron core which produces a specific amount of inductive reactance into a circuit. Turns Ratio See Ratio. Transformer A static electrical device which by electromagnetic induction transforms energy at one voltage or current to another at the same frequency. or load side connected to the secondary of the transformer in a circuit. Voltage Ratio See Ratio.