In House Repair

AC Motors
  • AC motors undergo extensive analysis prior to quotation and repair. Every attempt is made to determine the root cause of failure. Insulation condition, core condition, and mechanical fit dimensions are recorded and compared to standards. Machine shop work is performed in-house.
  • Our Stator reclaiming oven is equipped with a chart recorder and water mist over-temp suppression system. Epoxy resin is used in all rewinds. VPI system capacity is 9′ diameter by 9′ deep. Random coils are wound on Samatic numerically controlled machines.  Final test voltages available up to 7200 volts.
  • AC stators and rotors, and DC armatures are tested prior to and after stripping to ensure the integrity of the laminations before winding. Full documentation is made of “as found” and “as repaired” conditions.
DC Motors
  • Direct Current (DC) motors are found in multiple industrial applications where high torque and variable speed are required. Darby Electric has the written procedures, trained technicians, instruments and machines to perform a total disassembly and analysis and completely rebuild all sizes of DC motors.
  • TIG Welded Connections – Tungsten Inert Gas (TIG) welding is used to connect the armature coil leads to the commutator riser. This method of attaching copper leads to copper commutator risers produces a high strength, low resistance joint free of contaminates. This assures electrical, mechanical and thermal life.
  • Shaft Currents – The primary cause of damaging circulating currents in DC Motors is due to the loss of interlaminer insulation in the armature laminations. All DC armatures should be checked for damaged iron during disassembly and analysis. Assembled motors can be checked for shaft currents with a Rogowksi coil.


Rotor Rebuilding

Darby Electric Company is a full service rotor rebuild facility providing the highest quality repair in the shortest time possible. We analyze and duplicate the bar end ring shape, size and material. Replacement laminations and shaft repair are available. Click here to receive a quick quote.

  • Squirrel Cage Induction Rotors
  • Lamination Restacking, Replacement, and Refurbishment
Servo Motors
  • Servo Motor Repairs:
Darby Electric Company has the expertise and equipment to evaluate, repair and test run most models. We offer a one-year warranty on repair and materials. We also have the capability of load testing both AC and DC servo motors.
  • Darby Electric stocks a vast variety of commonly used bearings and seals. We have dedicated electronic test equipment for testing, analyzing and documenting data. This is vital for servo repair, not only for troubleshooting but also for the electronic setup prior to installation. Mitchell feedback diagnostic allows us to have the means to accurately test feedback devices. We also have means to surge test stator, armature and some control devices by the use of a Baker Surge tester.
Aerators and Spray Coolers

Aerator motors are rebuilt when your current motor fails. At Darby, we have a unique, proven process to get you up and running quickly. Learn More


Split Case and Submersible

Explosion Proof Motors

We can relist your UL certified motors.

Vacuum Pressure Impregnation with Epoxy Resin


Utilizing a 9-foot Imprex VPI system, with Von Roll Permafil Epoxy Resin, Darby Electric is able to document resin saturation of processed equipment. This process, in conjunction with a calibrated oven monitoring system, results in an excellent solution for your rewind needs.

Dynamic Balancing to 25,000 lb 9’ Diameter


Unbalance in the rotating assembly affects the forces imposed on the bearings, increases motor losses and decreases the motor efficiency.
  • Unbalance is caused by the unequal distribution of weight about the rotating centerline. Unbalance is the major cause of motor vibration. Darby Electric has two Schenck balance stands (H4, 2500 lbs and H5, 10,000 lbs) and one IRD stand (B200, 25,000 lbs). There are two Schenck microprocessors in use with the three stands. Darby Electric has Schenck VP30 and VP41 portable balancers to use in the field.
Full Machine Shop Capabilities

Journal, Housing and Seal Fit Repair

  • Synchronous Motors
  • Gearboxes
  • Reducers
  • Hermetic Motors
  • Shaft Repair, Straightening, and Replacement