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:
Feb. 20, 1979
Filed:
Sep. 15, 1977
Applicant:
Inventor:
Paul Greenhough, Cleck Heaton, GB;
Assignee:
Dresser Europe S.A., Brussels, BE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318822 ;
Abstract
A mining machine includes drive unit means for driving a haulage winch and a cutting tool of the machine, the drive unit means comprising a multi-phase induction motor with a wound rotor. In order to control the motor speed, the motor is provided with a circuit connected across the rotor windings and means for varying the effective impedance presented by the said circuit to the rotor windings.