SIL 449.00 TO: FROM: SUBJECT: MODELS: August 8, 2011 LeTourneau, Inc. Dealers and Users LeTourneau, Inc. Service Department Motor Flashover Troubleshooting Machines with DC motors and LINCS (L-1350, L-1850, L-2350) Page 1 of 3 DC traction motors in LeTourneau, Inc. equipment are a reliable and integral part of the drive train. Proper maintenance as shown in the “Taking Care of Your DC Motor" handbook will provide a long trouble free life. This handbook is in LeTrak KB 1195. However, when a motor experiences a failure it is important to determine the root cause prior to installing a new motor and putting it to work. The cause of the failure needs to be corrected to eliminate repeat failures and minimize operating costs. Determining the root cause is difficult unless all relative areas are examined at the time of the failure. Reference information for motor flashovers: 1. A J-2 flashover that primarily arcs from the back of the brush support ring to end bell usually indicates a failure which produces maximum current at low speeds. 2. A flashover from brush holder to brush holder and along the commutator riser usually reflects a problem related to high speeds such as commutator condition or current control. The following pages are provided as an outline of the areas that should be checked each time that a problem occurs. 2R3 SYSTEM The LINCS system can be an invaluable aide in determining the reasons or causes for motor flashover. 2011 Page 2 of 3 FLASHOVER TROUBLESHOOTING INTERNAL TO THE MOTOR MOTOR PROBLEM Internal short Armature coil Commutator Field pole Interpole Failure in the insulation of the interpoles or field poles.00 Description New SIL release Date 08/08/2011 . components Wiring from the current transformers Control fuses loose MAINTENANCE ISSUES Commutator High TIR High sawtooth High bar to bar Stall burned Loose – high TIR between brush paths Brush boxes Loose Improper height from comm Brushes loose in the box Wiring loose Springs Spring popped out Spring broken Spring not installed properly Brush installed backwards Brushes not seated properly Brushes wore down to pigtail Pigtails loose in the brushes USE YOUR LINCS 1.SIL 449. Neutral plane not set properly – burning on one side of brush.00 August 8. MOTOR STALL ALARMS ARMATURE CONVERTER ALARMS FIELD CONVERTER ALARMS GROUND FAULTS HIGH CURRENT ALARMS OVERSPEED ALARMS POWER BEING TURNED ON/OFF DURING VEHICLE MOTION MOTOR CURRENT MOTOR VOLTAGE Attachment: Traction Motor Inspection Form Revision SIL 449. EXTERNAL TO THE MOTOR Oil contamination – leaking pinion seal Water contamination Solvent contamination Dirt Wiring loose or damaged Cooling air restriction Gearing failure Vibration from Gearing Loose motor mounting Tires CONTROL SYSTEM CONTROLLER Card failure Controller phase transformer connections Controller phase transformer Panel feedback transformer Panel feedback transformer connections Controller wiring SCR PANELS SCR misfire Shorted SCR SCR with low resistance Panel with unbalanced SCR’s Panel failure – wiring. The LINCS data should be downloaded immediately following a flashover and analyzed with close attention paid to the following areas in the time preceding the flashover. Loose commutator Retorque commutator at rebuilder during overhaul or flash repair. 2011 Page 3 of 3 TRACTION MOTOR INSPECTION FORM GENERAL INFORMATION ON MOTOR AND MACHINE HISTORY .SIL 449.SECTION C 30) MOTOR INTERIOR CLEAN DIRTY DUST 31) COMMUTATOR GROOVED FILM 32) ARMATURE 33) POLE RING 34) FLASH RING (IF PRESENT) 35) BRUSH RING BURNED CHECKED WITH BOX GAUGE YES NO 37) BRUSH SRPINGS LOOSE YES NO 38) BRUSHES NO PROBLEMS SEATED BROKEN FRAYED PICTAILS SPRING PAD LOOSE OEM BRUSHES ALL BRUSHES SAME TYPE 36) BRUSH BOXES OIL IF MOTOR CLEANED UP WERE BOXES: REUSED REPLACED CLEANED UP QTY .SECTION B 17) ARMATURE MEG READING TO GROUND 26) ANY SCR’S SHORTED (CHECK BOTH DIRECTIONS) YES NO LOCATION 27)ARMATURE CONVERTER SCR MEGOHM READINGS 1 3 5 21) ARMATURE RESISTANCE 2 4 6 18) INTERPOLE MEG READING TO GROUND 19) FIELD MEGOHM TO GROUND 20) FIELD RESISTANCE 28) CONTROL SIGNALS WITHIN TOLERANCE (Use the checkout sheet and record all values) YES NO 29) ARMATURE IA WAVERFORM PROPER(with oscilloscope).00 August 8. Proper IA waveform at 100A YES NO Proper IA waveform at ½ of max stall current YES NO 30) CHANGE CARDS? LARGE STALL BURN LIST ALL CARDS THAT WERE CHANGED OUT: 22) COMMUTATOR: TIR MBTB 23) COMMUTATOR PROFILE SMOOTH SAWTOOTH SM MED 24) COMMUTATOR CONDITION 25) ARMATURE CONVERTER FUSES BLOWN YES NO QTY AND LOCATIONS 31) LINCS DOWNLOAD VISUAL CONDITION OF MOTOR .SECTION A 1) MACHINE TYPE 2) MACHINE S/N 3) MACHINE HOURS 4) DATE OF FLASH/FAILURE 5) MOTOR S/N 9) LOCATION LF RF LR RR OTHER 10) OPERATING MODE AT FLASH/FAILURE POWER RETARD/BRAKING UNKNOWN 11) DID MOTOR FLASH YES NO 12) SIGNS OF PREVIOUS FLASHING YES NO 13) RECORDS OF PREVIOUS FLASHING? YES NO 14) WAS TRACTION MOTOR: CLEANED UP REPLACED 15) OPPOSING MOTOR S/N 16) OPPOSING MOTOR HOURS 6) MOTOR OPERATING HOURS 7) MOTOR TOTAL HOURS 8) STATUS NEW USED ELECTRICAL CHECKS OF MOTOR AND CONTROLLER .