SEGI COLLEGE, SUBANG JAYAin collaboration with University of Sunderland COURSEWORK Laboratory Report (20%) ELX 214 Electrical Power System & Machines SUBMISSION DATE: NAME: ______________________________________________ ID: ___________________________________________________ GROUP MEMBERS: _____________________________________________________ __ _______________________________________________________ _______________________________________________________ LABORATORY ETHICS 1. Sign in the attendance sheet. 2. A student coming in 20 minutes after laboratory session has started will be considered ABSENT. 3. Switch off the hand-phone during laboratory sessions. 4. No eating and drinking inside the laboratory 5. Forbid make noisy or interfere other student. 6. Students must obtain PERMISSION from the instructor prior to leaving a laboratory session. 7. Students must do PRE-LAB assignments and understand the relevant worksheets, PRIOR to attending the relevant laboratory session. 8. Data acquired must approved by instructor (stamped and signed). 9. Data acquired by other students are not allowed and will be penalized heavily. 10. After complete the experiment, students must tidy the table, chair and equipments before leave the laboratory. ELX214 ELECTRICAL POWER SYSTEMS & MACHINES LABORATORY - REPORT EVALUATION No Criteria 1. Report format & Organization • General format and structure • Cover page, title, objective • presentation and tidiness Results • Results in the form of data, graphs etc. 3. 4. 5. 6 Discussion • Ability to present, inteprete, and analyse result • Compare with theoretical values @ ideal conditions • Answer questions or explain observations posed on lab sheet Conclusion • Provide answers to objectives stated earlier • Ability to learn something from the experiment Attitudes • Punctuality to the lab • Cooperatio n with group members. Excellent 4 Complete report and fully complied with criteria. Nice presentation. Good 3 Complete report and fully complied with criteria. Poor 2 Some criteria are missing. Poor presentation. Very Poor 1 Major criteria are missing, untidy, bad presentation Complete and accurate results, neatly presented Complete and neatly presented, minor mistakes Some points of discussion on results obtained covered and elaborated. Incomplete result, major mistakes Major data are missing Some points of discussion on results obtained covered but not properly elaborated. Very few points of discussion, not properly elaborated All points of discussion on the results obtained covered and elaborated. Weightage 2 4 4 The closing paragraph summarizes and draws a well developed conclusion Excellent The closing paragraph summarizes and draws a sufficient conclusion Good Total Score(max 56 ) = SUM{Score x Weightage} Total Marks (max 20)= Total Score/2.8 The closing paragraph attempts to summarize but draws a weak conclusion Fair Concluding paragraph is not apparent 2 Poor 2 Score Lecturer : ______________________________________________ Signature : _______________________________ Date: ________________ .*any part of the report suspected of plagiarism will be given zero mark. Therefore it must be as low as possible.EXPERIMENT 1:DC MACHINES LABORATORY 1.1.1. 1. 1. 1.3 FORMULAE PARAMETER Winding Voltage Winding Current Winding Resistance SYMBOL V I R UNIT Volts Amperes Ohms R=V/ I 1. It is calculated by applying known DC voltages and measuring the resulting current flows.1.1 MEASUREMENT OF THE WINDINGS RESISTANCE This experiment can be performed on various DC Machine.1 OBJECTIVES Calculate the winding resistance of various DC machines with the Volt-Ampere method (Ohms Law).2 THEORETICAL REVIEW The windings resistance cause internal voltage drops that reduce the machine’s efficiency.4 COMPONENTS DC Compound Excitation Machine DC Series Excitation Machine DC Shunt Excitation Machine Power Supply Cables Cables Support Voltmeter Ammeter Model A4240 Model A4242 Model A4244 Model A0240 Model A4890 Model A4891 With adequate range for this test With adequate range for this test .1. . . Repeat the above steps for all windings and calculate their resistance with the formula given above.Switch on the power supply. .1.6 EXECUTION The components must be connected as shown in the circuit diagrams and must be grounded. .1. Increase PS3 gradually by operating on the front knob. . It must be increased in 2% steps up to 10% max.C. Do not exceed 10 % of nominal winding voltage to avoid excessive winding temperature .Measure the voltage and current for any step and enter them in the worksheet tables.Set the D. MANUAL DATA COLLECTION AND ANALYSIS . windings voltage PS3 = 0 V. . . 1.2.2. 1. The area enclosed in the magnetization loop represents the power losses for magnetic hysteresis (residual magnetism) in the armature iron.3 MEASUREMENTS PARAMETER SYMBOL UNIT Armature Voltage V Volts Excitation Current le Amperes Speed n rpm 1. 1.2 MAGNETIC CHARACTERISTICS This experiment can be performed on shunt excitation DC generators. one for the ascending and one for the descending curves.1.4 COMPONENTS DC Shunt Excitation Machine Model A4244 Squirrel Cage Three Phase Drive Motor Model A4220 Power Supply Model A0240 Cables Model A4890 Cables Support Model A4891 Coupling Base Ammeter Model A4840 With adequate range for this test .1 OBJECTIVES Plot the magnetization characteristics of a DC machine. The resulting graph shows that for the same value of excitation current there are two different values of electromotive force.2.2 THEORETICAL REVIEW This experiment shows the electromotive force Eo against the excitation current le.2. Usually the medium value of Eo is considered. Voltmeter RPM Meter With adequate range for this test . . Switch on the power supply and adjust PS1 to nominal motor voltage. . .At each step enter in the worksheet table the values of voltage and excitation current .Plot the graph .When the motor is up to speed gradually increase the excitation current from 0% to 100% in 10% steps by adjusting PS4.Set the excitation voltage PS4 and drive motor supply voltage PS1 = 0 . The DC machine is mechanically coupled to the driving motor. MANUAL DATA COLLECTION AND ANALYSIS .6 EXECUTION The components must be connected as shown in the circuit diagrams and must be grounded.Repeat the above steps while decreasing the excitation current from 100% to 10% .1.2. . 3. 4. 4.1.1 OBJECTIVES The experiment is designed to measure the mechanical plus iron losses. brushes and .3.3 NO LOAD TEST This experiment is performed on shunt and compound excitation DC Machines.2 THEORETICAL REVIEW The mechanical losses are caused by friction on bearings. 1.3. They are not affected by the load and depend only on rotation speed. When in rotation.3 FORMULAE PARAMETER SYMBOL UNIT Armature Voltage Va Volts Armature Current Ia Amperes Input Power (no-load) P Watts Mechanical Losses Pm Watts Magnetic Losses Pfe Watts P=Va * Ia = Pm + PFe 1.4 COMPONENTS DC Compound Excitation Machine Model A4240 DC Shunt Excitation Machine Model A4244 Power Supply Model A0240 Cables Model A4890 Cables Support Model A4891 Coupling Base Model A4840 Ammeter With adequate range for this test Voltmeter With adequate range for this test RPM Meter .3. the rotor is subject to the alternating flux generated by the excitation winding on the stator and this causes the iron losses due to hysteresis and Eddy currents. Copper losses may be disregarded due to the low current absorbed in these conditions.ventilation. . . Switch on the power supply and adjust PS4 to nominal voltage.Decrease step by step the armature voltage and adjust the excitation voltage to keep the motor at nominal speed .1.Plot the graph .When the motor is at nominal speed measure the current and voltage and enter the values in the worksheet table .Choose a suitable stepping value and repeat the above procedure at each step .The experiment is completed when the armature voltage is so low that the motor begins to slow down . MANUAL DATA COLLECTION AND ANALYSIS .3.6 EXECUTION The components must be connected as shown in the circuit diagrams and must be grounded.Set the excitation voltage PS4 and armature voltage PS3 = 0 . Start the motor by gradually increasing the armature voltage PS3 . . . . 4. 1.4. The measured torque includes the losses on bearings.3 FORMULAE PARAMETER SYMBOL UNIT Armature Voltage Va Volts Armature Current Ia Amperes Excitation Current le Amperes . The torque’s value can be read in two ways: .2 THEORETICAL REVIEW The motor drives a loaded brake dynamo whose stator is mounted on bearings and capable of rotating.by a load cell connected to a torque meter . a dynamometer installed on its stator to counteract its rotation gives a reading of the motor’s torque. Measure its torque and mechanical power at various load conditions Calculate the motor efficiency Plot the load characteristics for analysis 1. they are small and do not affect significantly the experiments results.1. However.1 OBJECTIVES Find the motor’s working characteristics by loading it with a brake dynamo. ventilation and on collector brushes.4.4 DETERMINATION OF WORKING CHARACTERISTICS This experiment can be performed on various DC motors 1. Since the torque between its stator and rotor is proportional to the generated electrical power.by an arm and weights system The torque can be varied by varying the dynamo’s electrical load. Arm Length a m Weight G N Torque T Nm Speed n mm-i Excitation Current le A Input Power Pi Watts Output Power P0 Watts η Efficiency T= G*a Po = 2 π n T/60 Pi= Va*(Ia + Ie) η= Po/Pi 1.4 COMPONENTS DC Compound Excitation Machine Model A4240 DC Series Excitation Machine Model A4242 DC Shunt Excitation Machine Model A4244 Braking DC Generator Model A4430 Coupling Base Model A4840 Power Supply Model A0240 Resistive Load Model A4510 Starting Rheostat Model A4610 Excitation Rheostat Model A4630 Cables Model A4890 Cables Support Model A4891 Ammeter (Al. A2) With adequate range for this test Voltmeter (V) this test RPM Meter With adequate range for .4. . . 6 EXECUTION The components must be connected as shown in the circuit diagrams and must be grounded. Reduce the starting rheostat gradually. MANUAL DATA COLLECTION AND ANALYSIS - Set the armature voltage PS3 and excitation voltage PS4 = 0 and the starting and excitation rheostats to maximum resistance. Lock the counterweight. - Load the dynamo by varying the resistive load and level it by adjusting the excitation voltage PS4. Start the motor and ensure that the rotation is opposite to that caused by the weight. - Check and if necessary adjust nominal voltage PS3 - Enter the read values in the worksheet table - Move the weight to the other measurement values and repeat the above procedure - Plot the graphs of the load characteristics .1. - Adjust the speed to nominal value by varying the excitation rheostat. If necessary. - Move the weight to the maximum value indicated in the attached worksheet table.4. - Switch the power supply on. The motor must be coupled to the brake dynamo. exchange weights. - Level the dynamo by putting weights and counterweights on the graduated arm. - NOTE: measurements should be made as quick as possible to avoid overheating. . . 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