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. 17, 1981
Filed:
Dec. 13, 1978
Frank J Prines, Murrysville, PA (US);
Thomas C Matty, North Huntingdon Township, Westmoreland County, PA (US);
James H Franz, Murrysville, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A direct current motor power controlling chopper apparatus is disclosed which determines the operational speed of one or more traction motors propelling a passenger vehicle along a track. The speed of the motor is established by changing the ON and OFF conduction ratio or duty cycle relationship of a thyristor switch device to determine the field current and the armature voltage of that motor. The present apparatus can provide a greater controlled range of motor speeds including a lower minimum OFF operation and a full ON capacity. In addition, the present apparatus provides greater reliability due to less thermal stress on the thyristor switch devices and fewer circuit elements required to provide an improved motor current control operation.