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. 01, 2016
Filed:
Jul. 30, 2014
Hitachi, Ltd., Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A field winding type synchronous motor comprises a stator, a rotor with field windings, a brushless exciter, and a rectification circuit rectifying an output of the brushless exciter. A first circuit in parallel with the field windings includes a discharge resistor and a first switching device with a backward diode. The discharge resistor and the first switching device are connected in series. A second switching device is provided in one of the DC lines connecting the first circuit and the rectification circuit. The first switching device is controlled by a potential obtained by resistor dividing of an induced voltage in the field windings and a connection from the potential via a diode to anode adjacent to the rectification circuit on the one of the DC lines with the second switching device thereon. The second switching device is closed in a synchronous speed.