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:
Sep. 28, 1993
Filed:
Apr. 17, 1991
Hitachi, Ltd., Tokyo, JP;
Abstract
A control apparatus for an electric rolling stock makes it possible to use a single associated train in a variety of transit services including an express transit service to an accommodation train service. The apparatus comprises an induction motor controlled by an inverter. For an express transit operation (over a long inter-station distance), the ratio of output voltage and the frequency of the inverter is decreased to thereby increase a command current in a variable voltage/variable frequency region. For the accommodation train operation (over short inter-station distance), a control pattern reverse to the above is adopted. The electric rolling stock can adapt itself to the running conditions. Besides, the problem of overheating of the induction motor can be solved successfuly.