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:
Jun. 10, 1980
Filed:
Jul. 28, 1978
Robert Bosch GmbH, Stuttgart, DE;
Abstract
A controlled switch 4 provides current pulses derived from a battery 3 to a motor 1, having a series field 2 under command of a control unit 8 which provides command pulses for repetitive closing of the controlled switch 4. Current through the motor is sensed by a sensing resistor 6 and connected to a safety circuit 9 which, upon sensing of current flow in the absence of a control pulse from the unit 8, disconnects current to the motor by opening a controlled switch 5. To distinguish between (a) current flowing from the battery 3 l and (b) circulating current flowing during pulse gaps in a free-wheeling diode 7 connected across the field and armature of the motor, voltage across the free-wheeling 7 is sensed, thereby effectively sensing the conduction state of the free-wheeling diode and, if the free-wheeling diode is conductive, disabling the safety circuit to prevent spurious operation thereof during flow of inductive, circulating current through the bypass or free-wheeling diode under normal operation.