Ground fault detector
US4020394A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 20, 1976 |
| Grant date | Apr 26, 1977 |
| Priority date | — |
| Expiry date | May 20, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/331
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A ground fault detector for protecting an electrical power system against ground leakage currents. The detector is of the differential transformer type, in which the primary windings of the transformer are connected in series with the hot and neutral lines of the power system, any unbalance in the currents flowing through these lines being detected by sensing the unbalance voltage induced in the secondary winding of the transformer. The secondary voltage is amplified and employed to actuate a solenoid which trips the system circuit breaker in response to unbalance in line and neutral currents due to the flow of ground leakage current. A secondary winding on the solenoid is connected in the neutral line to cause the detector to operate in response to a neutral to ground fault, which might otherwise go undetected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.