Corona discharge monitor system
US4238733A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 15, 1979 |
| Grant date | Dec 9, 1980 |
| Priority date | — |
| Expiry date | May 15, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/1227
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A corona discharge monitor system for a dynamoelectric machine, particularly for large salient pole generators, has an antenna mounted on a rotor pole. The antenna sweeps over the stator slots and picks up radio frequency signals produced by corona activity occurring in the structure of the stator bars. A rotary coupler, having a rotating portion fixed to the shaft of the machine and a fixed portion adjacent to the rotating portion, couples the signal to a signal conditioner. A trigger signal synchronized with the rotor rotation and with a known reference to antenna position and derived from the power system line frequency, is used as one input to a storage device such as a variable persistence oscilloscope. A first output of the signal conditioner represents the peak amplitude of the corona discharge and a second output represents the number of corona occurrences and these are applied to the storage device. A display is provided with reference to the trigger signal in such a way as to associate the first or second output with each slot, or if not a particular slot, at least within a limited number of slots.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.