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:
Jun. 25, 1991
Filed:
Dec. 16, 1988
Takao Kuwabara, Hitachi, JP;
Hisao Inoue, Hitachi, JP;
Hiroto Nakagawa, Mishima, JP;
Eizo Kita, Kyoto, JP;
Hitachi, Ltd., Tokyo, JP;
The Kansai Electric Power Co. Ltd., Tokyo, JP;
Abstract
The operation of a variable speed electric driven pump turbine is monitored continuously during pumping to detect the operation point of the pump turbine, and to prevent it from falling into a hump characteristic region, which is recognizable on a graph of total dynamic head versus flow rate. Stalling occurs in the hump characteristic region as a result of a partial reverse flow of the water with respect to the runner. When the operation point of the pump turbine approaches the hump characteristic region, a corrective action is taken that includes increasing the output level of the electric driven pump turbine to increase its rotating speed, temporarily.