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. 30, 1988
Filed:
Aug. 14, 1987
James N Krause, Santa Clara County, CA (US);
Seagate Technology, Scotts Valley, CA (US);
Abstract
The magnetic hysteresis or magnetic memory error in a stepper motor is erased by sequencing the motor phases in a particular manner. In positioning a transducer by energizing selected phases of the stepper motor, the sequence is selected to eliminate the memory of the previous stepper motor position, and reinforce only the new position. This cancellation is achieved by activating the stepper motor to move a transducer from a given track position to an adjacent track position, the sequence of energization of the phases including at least one reversal of the magnetic sense of each phase that was energized to position the transducer at the initial track, but that is not to be energized at the target track; further, the phases not energized at the initial track but that are energized at the target track are reinforced by the selective energization during more than one of the steps used for reaching the target track.