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:
Apr. 18, 1995
Filed:
Dec. 17, 1992
Ralph Oosthuizen, Johannesburg, ZA;
Eimco Mining Machinery (Proprietary) Ltd., Transvaal, ZA;
Abstract
The invention relates to apparatus for controlling a plurality of electric motors. The apparatus includes drive means for applying electrical power to the motors at a predetermined current or voltage. Sensor means are provided for sensing the load on each motor. Comparator means, which include polarity detection means for generating at least one polarity signal representative of the combined polarity of the loads, and summing means for deriving a magnitude signal representative of the loads, are used to determine the relative magnitudes of the loads. Control means are arranged to generate a compensation signal which is applied to the drive means to reduce the power applied to the more heavily loaded motor or motors. The control means typically includes switching means responsive to the polarity detection means for determining the polarity of the magnitude signal, thereby to obtain the compensation signal. The invention extends to a method of controlling a plurality of electric motors.