When First Energy’s motor failed in service, they came to 3-D Service for a rapid yet quality repair. The 2,500 HP, 4,160 Volt Allis Chalmer AC motor arrived by permitted-load weighing 45,000 pounds. Through incoming inspection and testing, it was determined the stator shorted due to water in the stator, necessitating a complete rewind.

As part of the re-wind, 3-D Service upgraded the turn insulation and increased the copper cross section so the motor will run cooler and have better reliability. The stator was vacuum pressure impregnated (VPI) with an additional epoxy overcoat. VPI was chosen because it provides sealing, electrical insulation, and mechanical support of the windings.

In addition to rewinding the stator, the rotor was cleaned using dry ice blasting. Using dry ice, CO 2 pellets that are propelled through a nozzle with compressed air, dry ice blasting is an effective way to clean contaminants from surfaces while preserving surface integrity and critical tolerances.

Due to the unexpected failure, the rewind was completed on a rush basis and shipped back to First Energy four days ahead of schedule. For a complete overview of 3-D Service’s generating station services, click here.