Donald R Leonard

US Patent:

56940440, Dec 2, 1997

Filed:

Nov 13, 1995

Appl. No.:

8/559166

Inventors:

John Llewellyn Crowley - Beavercreek OH
John David Painter - Wilmington OH
James Timothy Dillon - Kettering OH
David Allan Boyer - Miamisburg OH
James Allen Fisher - Dayton OH
James Hubert Walters - Beavercreek OH
Donald Christopher Leonard - Beavercreek OH

Assignee:

Fisher Data Products, Inc. - Dayton OH

International Classification:

G01R 3106

US Classification:

324546

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.