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:
Jan. 08, 2002
Filed:
Nov. 08, 2000
Takao Kuwabara, Hitachi, JP;
Kei Katayama, Hitachi, JP;
Hiroto Nakagawa, Osaka, JP;
Haruki Hagiwara, Himeji, JP;
Other;
Abstract
An object of the present invention is to provide a pump turbine capable of improving the stability of the governor by fully lessening the influences by the S-characteristics even when the running point of the pump turbine is in the S-characteristics region. For this purpose, in a pump turbine comprising a runner which is coupled with a generator motor, discharge control apparatus for controlling the quantity of water passing through the runner, and a governor for controlling said discharge control apparatus to keep the runner speed at a predetermined speed, the arithmetic apparatus of said governor is controlled to temporarily open said closing discharge control apparatus in the leading half of the speed decrease or earlier after the first speed increase upon a load rejection turns to a speed decrease upon a load rejection which abruptly shuts off power from the generator motor, so that the rotational speed of the runner goes down at much slower rate than the rate of increasing immediately after a load rejection.