Control circuit for electromagnetically operated contactor
US4214290A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 18, 1977 |
| Grant date | Jul 22, 1980 |
| Priority date | — |
| Expiry date | Mar 18, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H47/325
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control circuit for controlling the current supplied from a d.c. source such as a battery to the actuating coil of an electromagnetically operated contactor, comprising switching means such as a transistor operable repetitively to connect the coil to and disconnect the coil from the source, and control circuit means for varying the mark-to-space ratio of the switching thereby to vary the mean voltage applied to the coil. The mean voltage can be controlled so that the mean current through the coil when the contactor is closed remains substantially constant irrespective of the voltage of the battery, so that the same contactor and control circuit can be used with a number of batteries of different voltages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.