Method of nondestructive insulation test and a nondestructive insulation testing apparatus
First Claim
1. A method of nondestructive insulation testing, comprising the steps of:
- (a) placing an electric device having a core and at least one winding provided on said core in a reduced atmospheric pressure;
(b) insulating said core from the ground;
(c) supplying a voltage signal having a surge waveform to said winding; and
detecting a glow discharge which may result from step (c) to detect an insulation condition of said winding.
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Accused Products
Abstract
A method of nondestructive insulation testing is disclosed which comprises the steps of: (a) placing an electric device, having a core and at least one winding provided on the core, in a reduced atmospheric pressure; (b) insulating the laminated core from the ground; (c) supplying a voltage signal having a first surge waveform to the winding; and detecting a glow discharge which may result from step (c) to detect an insulation condition of the winding, wherein the reduced atmospheric pressure ranges from 65 to 75 Torr and the voltage signal is applied in the first direction of the winding and then, is applied in the second, opposite, direction of the winding. This method may further comprise steps of: (d) supplying a second voltage signal having a second predetermined surge waveform having a peak voltage lower than a peak voltage of the predetermined surge waveform; (e) outputting a second output signal between the winding indicative of a second insulation condition of the winding in response to step (d); (f) measuring intervals corresponding to the wavelengths of the output signal and the second output signal respectively; and (g) judging the insulation condition by comparing the measured intervals to each other. A nondestructive insulation testing apparatus is also disclosed.
12 Citations
9 Claims
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1. A method of nondestructive insulation testing, comprising the steps of:
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(a) placing an electric device having a core and at least one winding provided on said core in a reduced atmospheric pressure; (b) insulating said core from the ground; (c) supplying a voltage signal having a surge waveform to said winding; and detecting a glow discharge which may result from step (c) to detect an insulation condition of said winding. - View Dependent Claims (2, 3, 4, 5)
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6. A nondestructive insulation testing apparatus for detecting an insulation condition of an electric device, having at least one winding, insulated from the ground at a reduced atmospheric pressure comprising:
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means for insulating said electric device from ground; means for maintaining said electric device at a reduced atmospheric pressure; surge voltage signal supplying means for supplying a first voltage signal having a predetermined surge waveform to said winding; and signal output means for outputting an output signal between ends of said winding having a wavelength indicative of an insulation condition of said winding. - View Dependent Claims (7, 8, 9)
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Specification