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:
May. 16, 1978
Filed:
Mar. 07, 1974
Francis T Thompson, Murrysville, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
An electric vehicle having a separately excited field controlled direct current drive motor powered by a direct current power supply wherein the field currents supplied to the drive motor and the armature currents drawn by the drive motor are responsive to safety control features provided on the electric vehicle. Speed control is provided for preventing overspeed of the drive motor by applying full-field current when the drive motor speed exceeds a selected value. If the motor speed remains above the selected maximum value and armature current remains positive, indicating the drive motor is not providing regenerative braking for the electric vehicle, then the contactor connecting the direct current power supply to the armature of the drive motor is opened. The electric vehicle is also provided with an armature current limiting means which causes full-field current to be applied if the armature current exceeds some maximum value. If the armature current remains above the selected maximum value then the armature of the direct current drive motor is disconnected from the power supply. Control of the field current is provided for limiting field current to a maximum value and assuring that a minimum value of field current is always supplied to the drive motor during operation. Throttle override is provided when the throttle is less than 5% depressed causing an increased value of field current to be supplied to the direct current drive motor, resulting in regenerative armature current flow and braking of the vehicle. The throttle control is constructed to be failsafe and demand regeneration if open circuited. Brake override of the throttle is provided on the electric vehicle so that applying the brake cancels any throttle demand signal and causes full-field current to be supplied, resulting in maximum regenerative braking. A temperature sensor is provided in the direct current drive motor which activates a control, when the temperature of the drive motor exceeds a preselected value which alters performance, so that the vehicle can only be operated at reduced performance thus allowing the drive motor to cool.