Ground fault detector
US4234900A · kind A · utility
8Cited by
3References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1979 |
| Grant date | Nov 18, 1980 |
| Priority date | — |
| Expiry date | Apr 3, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/33
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A sensed current resulting from the occurrence of a ground fault is amplified by a differential amplifier and applied to a waveform shaper after having been delayed. The waveform shaper includes two complementary transistors interconnected into a thyristor and a transistor for amplifying the delayed current from the thyristor to a constant current under the control of a negative feedback transistor. The constant current is applied to a thyristor to turn it on to activate an associated circuit interrupter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.