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:
Dec. 13, 1988
Filed:
Aug. 31, 1987
Terry J Ahrendt, Gilbert, AZ (US);
Allied-Signal Inc., Morris Township, Morris County, NJ (US);
Abstract
A stepper motor shaft position sensor differentiates the current provided when the stepper motor is excited as by a step command voltage. The differentiated current is, in effect, a signature indicative of whether or not the motor shaft has taken a step. If the differentiated current falls below a predetermined level within a predetermined interval the motor shaft has taken a step as indicated by a sensor output at a predetermined logic level. Otherwise, the sensor output is at another predetermined logic level indicating that a step has not been taken and the motor is in a stalled condition. The sensor output is applied to a utilizing means which provides a continuous verification of the steppper motor shaft position.