Three phase throttle current technique
US5519558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1993 |
| Grant date | May 21, 1996 |
| Priority date | — |
| Expiry date | Dec 30, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/025
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A current throttle resistor external to a contactor device protects an electrical power distribution circuit coupling a load to a power line. The contactor has electrical switching contacts in series with the load and the line, and for example, an electromagnetically controllable switch for opening the contacts. A current sensor is coupled to the controllable switch for opening of the contacts upon occurrence of a high current fault in the power distribution circuit exceeding a predetermined threshold. A resistive element in series with the power distribution circuit between the line and the load, provides a voltage drop for limiting current during the high current fault. The resistive element can be a nichrome strip or similar positive temperature coefficient resistance having a low cool resistance, and is thermally isolated from the controllable switch by mounting in a resistor housing external to the contactor. To maximize resistance and minimize space, the nichrome strip is bent in an elliptical arc between two leads that protrude from the resistor housing, for coupling into the circuit on the load side of the contactor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.