Abstract: A testing surge tests all of the individual coils within a coil assembly or multi-coil winding simultaneously. A pickup device is positioned adjacent each of the coils being tested. A voltage pulse is applied across the multi-coil winding. Each of the pickup devices generates a signal having a waveform representative of the magnetic field generated by the coil adjacent thereto in response to the voltage pulse. These signals are compared to each other to identify insulation defects, winding defects and polarity problems within the coils.

Abstract: A circuit detects insulation defects in a coil assembly including a plurality of series connected coils. A first voltage pulse is applied to a first coil of the coil assembly, a second voltage pulse is applied to a second coil of the coil assembly, the first and second coils being substantially diametrically opposite to one another, and the first and second voltage pulses being substantially equal to one another and oppositely poled relative to the coil assembly. A first voltage waveform across the first coil is monitored, and a second voltage waveform across the second coil is monitored. A first signal is derived from the first voltage waveform, a second signal is derived from the second voltage waveform, and a differential percentage value based on the first signal and the second signal is computed. An insulation defect is then determined based upon the differential percentage value.