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. 21, 1978
Filed:
Feb. 09, 1976
Frank S Buchwald, Beachwood, OH (US);
Ward L Bivens, Painesville, OH (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A DC electrical motor of the form having one field winding connected in series with the armature winding in addition to a shunt field winding connected in parallel with the armature winding is provided with a diode or the like in the shunt field winding circuit. This blocks reversed current flow in the shunt field winding which can otherwise occur during start-up due to an inductive interaction with the series field winding and armature circuit. The diode or the like enables faster magnetization of the stator poles by preventing creation of negative shunt field ampere turns due to the magnetic couple with the series field-armature circuit during the motor start period. Faster starting of the motor results, and adverse effects such as heating, brush deterioration, and commutation problems are reduced.