The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 22, 1980
Filed:
Mar. 18, 1977
Albert E Sloan, Gateshead, GB;
Sevcon Limited, Gateshead, GB;
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.