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:
Aug. 15, 1978
Filed:
May. 18, 1977
Jean Roger, Conflans Ste Honorine, FR;
Aciers et Outillage Peugeot, Audincourt, FR;
Abstract
A device for limiting the current in an a.c.motor having a commutator adapted to be supplied with current by a single-phase current source. The device comprising a triggerable silicon-controlled rectifier component connected in series with the motor and in parallel with an RC phase-shifting circuit furnishing the control voltage of the rectifier component. The capacitive branch of the RC circuit is connected in parallel with a shunt circuit which shunts a certain quantity of the charging current of the branch for modifying the trigger instants of the rectifier component. The shunt circuit comprises two transistors of opposed conductivity types which are connected with a common emitter configuration, the collector-emitter circuits of the transistors being connected in parallel with the capacitive branch. The limiting device further comprises a control circuit furnishing two d.c. control signals whose magnitudes are a function of the intensities of the two half-cycles of the current flowing in the rectifier component. The bases of the transistors are respectively subjected to the control signals so that the shunt circuit can shunt, beyond a predetermined current threshold of the current in the motor, a notable part of the two half-cycles of each period of the current.