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:
May. 26, 1987
Filed:
Apr. 28, 1986
Masami Nomura, Inazawa, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a case where a braking torque is required as in the slowdown mode of the cage of an elevator, regenerative power within a range within which the generation of heat by a motor is permissible is consumed in the motor, and excess regenerative power is consumed by a regeneration resistor, so that a control apparatus can be made smaller in size. A braking torque is controlled in such a way that when a braking torque command is not greater than a predetermined value, only the magnitude of current is controlled with a slip fixed, and that when the braking torque command has exceeded the predetermined value, the slip is decreased without increasing the magnitude of the current. Regenerative power is partly fed back to a D-C side. Since, however, the current is suppressed within a predetermined value, so that the current capacity of an inverter can be restrained and that the resistor for consuming the regenerative power on the D-C side does not increase considerably. Moreover, since the power to be consumed in the motor decreases, the heat generation of the motor can be suppressed. Thus, a system with a thermal balance considered as a whole can be constructed.