This company is both a industrial electric motor repair company and a test system company. They do great work and have electric motor repair stands for sale. Located in Charlotte North Carolina.
Also consider www.atidayton.com. They are located in Dayton Ohio.
An inexpensive instrument has been designed to detect shorted turns in three-phase motor windings while the motor (any type of three-phase motor) is powered, running, and loaded. The turn-to-turn short may be used as a “predictor” of future insulation life. This measurement is accomplished by continuously monitoring and comparing the inductance of each of the three phase windings using a specialized transformer and proprietary analogue circuitry. A prototypical instrument has been built and shown to be sensitive to small relative inductance changes in the presence of “mains” (60 Hz) currents up to 15 A. The instrument also serves as a continuous ground fault monitor and detects phase-to-phase faults. The instrument can also be used for “acceptance” testing.