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:
Mar. 19, 1985
Filed:
Jan. 10, 1983
Werner F Thommen, Staefa, CH;
U.S. Philips Corporation, New York, NY (US);
Abstract
A stepping motor (M) with a self-inductance L is energized with pulses. If the motor current i.sub.m is less than a reference value I.sub.R =V.sub.ref /R.sub.o, the motor is connected to the battery and if i.sub.m is greater than I.sub.R the motor is short-circuited. The motor current therefore fluctuates around the value I.sub.R. The motor current is adjusted so that the average voltage during a first measuring interval, in the range of the maximum angular velocity, is twice that during a second measuring interval at the end of the energizing phase. The two average voltages are compared with each other by measuring the time during which the switch (S) is in the energizing position. In this way it is not necessary to measure the voltage induced in the self-inductance L and every motor pulse is checked constantly. The motor current is adjusted at the end of the energizing phase to provide a correct adaptation to the required motor torque. Tolerances of all the elements involved, including the motor, are automatically compensated.