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:
Nov. 20, 1984
Filed:
Jun. 23, 1982
Rodime Limited, , GB;
Abstract
In a disk drive system which uses as stepper motor, overshooting of the desired final position is reduced by short-circuiting the windings of the stepper motor which normally remain open-circuit or are switched off. This short-circuiting provides a current path for any EMF induced in the unused windings. This effect is achieved by connecting a pair of transistors in parallel with each other and with each respective winding. The transistors are connected in opposite polarity to provide a short-circuit regardless of the polarity of the EMF across the windings. The transistors are connected to a microprocessor which is programmed such that the windings are selectively short circuited and the short circuits are applied at a predetermined time with regard to the step so that `damping` is optimized. The microprocessor may be programmed to switch the transistors on and off as desired giving flexible timing to suit different conditions. One or more stepper motor steps may be treated in this manner.