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:
Nov. 24, 1987
Filed:
Dec. 20, 1985
Katsumasa Shinmei, Hitachi, JP;
Kazuo Niikura, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A method of starting a variable-speed pump turbine or a variable-speed pump driven by a variable-speed generator motor or a variable-speed motor connected to an electric power line in parallel therewith. The generator motor or the motor is first operated at low speed with the guide vanes or the delivery valve fully closed. The low speed is lower than a stable starting speed of the pump turbine or the motor but high enough to prevent backward flow of water into the pump turbine or the pump. After the operation is set at the low speed, the guide vanes or the delivery valve are opened and the opening degree is gradually opened until the speed is increased to a speed optimum for the steady operating condition of the pump turbine or pump. This method effectively suppresses abrupt increase in the pump input power required for the driving of the pump turbine or the pump, whereby unfavorable effect on the electric power line is avoided advantageously.