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. 11, 1999
Filed:
Mar. 27, 1997
Ajay P Mishra, Cannonsburg Township, Washington County, PA (US);
ABB Daimler-Benz Transportation (North America) Inc., Pittsburgh, PA (US);
Abstract
An electric powered vehicle includes a traction motor powered from a source of switched DC power. The motor includes a tachometer for measuring the rotational velocity of the motor and for providing a tachometer signal indicative thereof. A low pass filter low pass filters the tachometer signal and produces a reference tachometer signal. A summing circuit combines the tachometer signal and the reference tachometer signal to produce a deviation signal. The deviation signal is provided to a signal processing circuit which includes a comparator and a reference value generator. The comparator compares the output of the summing circuit to a reference value provided by the reference value generator and produces a binary changing signal as a function of the comparison. A controller, which controls the rate DC power is switched to the motor, accumulates a count of the comparator signals over a predetermined interval and terminates the provisioning of power to the motor if the accumulated count exceeds a predetermined value.