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:
Oct. 16, 1984
Filed:
May. 17, 1982
David W Collins, Rochester, MN (US);
John J Neesz, Rochester, MN (US);
Michael C Stich, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A three level motor speed control for a device such as a magnetic disk drive requiring a closely regulated running speed provides for acceleration, deceleration, obtaining close speed regulation and maintaining speed regulation of a rotating device during operation. The first level control provides acceleration or deceleration while checking velocity each eighth revolution and the second level control uses single revolutions to measure speed over an accurate rotational distance to obtain close speed regulation. Both level one and level two are controlled by the device controller. During run conditions with no error signal, a third level of control of the closely regulated velocity is maintained by separate hardware circuits which frees the processor for other uses. An error condition forces control to level one for re-establishment of the regulated running speed and a command to stop the drive forces control to level one for deceleration and stop procedures.