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. 20, 1979
Filed:
Oct. 13, 1976
Lester A Price, Greenfield, WI (US);
Gerold E Schmid, Brookfield, WI (US);
Lawrence A Millonzi, Milwaukee, WI (US);
Harnischfeger Corporation, W. Milwaukee, WI (US);
Abstract
There is disclosed a squirrel-cage motor for a winch drive or other application and control means for operating the motor in hoist or lower directions at any one of a plurality of speeds in either direction. The motor and winch are provided with a load brake. In one embodiment, the stator comprises two stator windings having different numbers of poles to provide high speed (fewer poles) and low speed (more poles) windings. The control means comprises a direct current power source, an alternating current power source, means for connecting the sources to the stator windings so that different speed points and braking operations are achieved, and means for operating the load brake. Low speed results from simultaneously energizing the low speed winding and the high speed winding from the alternating current power source and the direct current power source, respectively. Intermediate speed results from energizing only the low speed winding from the alternating current power source. High speed results from energizing only the high speed winding from the alternating current power source. The control means includes time delay means to prevent connection of the alternating current source to the winding previously energized from the direct current source until arcing across a direct current contactor in the control means ceases during transition from low speed to higher speed.