Field overvoltage protecting apparatus for synchronous machine
US4118749A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1977 |
| Grant date | Oct 3, 1978 |
| Priority date | — |
| Expiry date | Mar 30, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/0805
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus for protecting a synchronous machine from a field overvoltage is disclosed. The apparatus comprises a field excitation control circuit which is impressed with the armature voltage of the synchronous machine so as to provide a DC power supply for producing a DC output to excite the field winding of the synchronous machine, a first discharge circuit which is adapted to discharge the stored energy of the field winding when the synchronous machine is to be tripped under predetermined conditions, and a second discharge circuit for reducing the field voltage by allowing a field current to flow therethrough in response to generation of an overvoltage whose absolute value is higher than a predetermined level, across the field winding. The resistance of the second discharge circuit is selected to be higher than that of the first discharge circuit so that even in the presence of an overvoltage across the field winding, the overvoltage is suppressed by the second discharge circuit thereby to prevent frequent tripping of the synchronous machine due to overvoltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.