Serving the Central Valley’s Needs Since 1913 www.electricmotorshop.com

When the 200 HP motor arrives at our facility, it is first photographed to document its condition, and to record all of the components that come in with it, such as coupling and connection boxes or fan and covers. All the nameplate data is recorded and a job card is started. This card will follow the motor throughout the whole procedure until it's ready to go out the door. The first step in repairing the motor is to preform a series of static tests on the windings to see what condition they are in. These tests consist of meg ohm resistance and Surge testing to determine the integrity of the insulation. If the motor passes the static test then the motor is connected and run to check the motor’s mechanical condition. The disassembly process includes checking the shaft for trueness, disassembling the motor and removing the bearings and rotor. All machine fits are inspected and measured comparing them to industry standards. Visual inspection is conducted noting any problems that need to be addressed such as cracked housing, damaged fans or other parts. The rotor is then tested to see if it has good rotor bars, which are important for proper motor operation. The stator is visually inspected. In this case the windings are shorted and the stator will need to be rewound. The stator is prepped for the burnout process. The windings must be burned in order to remove them. At this point a core loss test is performed using a computerized LEXSECO tester, to test the integrity of the iron prior to the burning process. The stator is then placed into one of our two state-of-the-art temperature and flame controlled ovens to burn the insulation from the winding without overheating the laminated stator iron. The burnt windings are then pulled from the slots in an orderly process to record the turns, pitch and wire size. The stator iron stack is repaired if needed and prepped. The iron is coated with an enamel insulating finish and the NOMEX insulation papers are installed. New coils are wound on the SOMATIC coil machine and are staged for installation. Coils are inserted into the slots and phase insulation is installed between coils in the slot. Coils are hand inserted carefully to prevent damage to the wire insulation. The ends of the coils are connected to the proper configuration for the windings design. The end turns are secured tightly together. The stator is then electrically test for quality assurance. The stator is ready for varnishing. Our method for this is VPI ( Vacuum Pressure Impregnation) in a resin that will fill any voids in the windings and laminations. This forms a void-free insulation that prevents air pockets that can build up contaminates, reduces the natural vibration of a winding and allows for better heat transfer. The stator is baked in a temperature controlled oven to cure the epoxy. The rotating elements (rotor, fans, pulleys, etc.) are dynamically balanced to below Precision industry standards. The motor is now ready for assembly. The rotor is carefully inserted into the stator. The bearings and the end housings are installed. The motor windings are once again surge-tested and hi-potted for the final time. The motor is then test-run at full voltage, and a vibration test is done. This information is recorded for the final report.