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. 25, 1994
Filed:
Nov. 20, 1991
Takanobu Masaki, Inazawa, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A drive control unit for a hydraulic elevator comprises: an inverter for variably driving the motor; a speed detector for detecting a rotating speed of the motor; a current detector for detecting a primary current of the motor; a speed control, unit for calculating a torque command value to the motor according to a deviation between the rotating speed detected by the speed detector and a speed command value; a torque control unit for controlling the inverter according to the rotating speed detected by the speed detector, the primary current detected by the current detector and the torque command value calculated by the speed control unit; a pump pressure detector for detecting the pump pressure of the hydraulic pump; a limiting means for limiting the torque command value output from the speed control unit when the pump pressure, detected by the pump pressure detector, decreases below a set value.