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. 28, 2000
Filed:
Feb. 27, 1998
Takao Kuwabara, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An upper reservoir-side conduit or a lower reservoir-side conduit is branched in the vicinity of pump-turbine ends and at least a first pump-turbine out of a plurality of pump-turbines which share the conduit portions located farther than the branch points with the other pump-turbine or pump-turbines is provided with a rotational speed increase detector. When it is detected that the rotational speed of the first pump-turbine has exceeded a second predetermined value higher than a rated speed, a command is issued also to at least one of the other pump-turbines to limit the guide vane closing speed in that pump-turbine to a speed approximately equal to or lower than the speed after the shift to a slow closing of the guide vanes.