Solid state trip unit for an electrical circuit breaker
US4380785A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1981 |
| Grant date | Apr 19, 1983 |
| Priority date | — |
| Expiry date | Mar 17, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/222
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention concerns a solid state trip unit having long time delay, short time delay and ground fault trip circuits. It comprises a metering resistor (40) electrically connected in a series circuit (42) including additionally a power supply (44) for the trip circuits LR, CR and H, and a trip coil (22). A switch (52) connected in parallel with the coil (22) which may be either in an ON-state to shunt the coil (20), or in an OFF-state after a trip signal is delivered from one of the trip circuits, so as to cause an increase of the impedance of the series circuit (42) and the excitation of the trip coil (22). The trip unit can be applied to low-voltage circuit breakers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.