Electrical protection circuits
US4177492A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 1978 |
| Grant date | Dec 4, 1979 |
| Priority date | — |
| Expiry date | Jan 16, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit arrangement is disclosed for protecting against overload electrical equipment such as an electric motor, and any mechanical equipment driven thereby, such as a power actuator. Two light emitting diodes are connected in parallel with each other (with opposite polarity) and in parallel with a series impedance in the power supply circuit of the motor so that each produces a light output in response to an overload current of appropriate polarity in the motor. Associated with each diode is a respective phototransistor which responds to the light output from the associated diode and, via a respective control circuit, operates a switch to interrupt the load current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.