Abstract: A method and device for distinguishing between partial discharge and electrical noise in high voltage conductors such as in motor and generator stators, power cables, gas insulated switchgear and other equipment where high voltage insulation is subject to deterioration. A series of comparators sets a trigger threshold and a voltage range, set by a computer, whereby pulses falling within the voltage range are sampled at four short intervals and then four longer intervals to produce a general pulse width profile. The voltage range is varied by the computer so that a number of voltage ranges are sampled during each selected portion of an ac cycle. The pulse width of pulses falling within each voltage range is recorded by the computer, and displayed graphically. In a preferred embodiment the device is provided with two channels, for receiving a signal from each end of a partial discharge detector described in U.S. Pat. No. 4,949,001.

Abstract: An electronic rotor temperature sensor which is encased in a plug or housing which can be removably mounted in the rotor of a generator or motor and transmit r.f. signals encoded with temperature information.

Abstract: In order to determine the occurrence of a stator fault in an induction motor during operation of the motor, the axial leakage flux is monitored during operation of the motor. The occurrence of a stator fault is detected by observing a change in selected harmonic components of the axial leakage. The angular position of the fault with respect to a datum position is determined by noting and recording changes in the axial leakage flux at a plurality of positions distributed symmetrically around the axis of the motor and computing the angular position by triangulation. The axial leakage flux is detected by individual search coils located at said plurality of positions.