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:
Sep. 03, 2002
Filed:
May. 06, 1999
J. Stephen Thorn, Florissant, MO (US);
Arthur E. Woodward, Manchester, MO (US);
Ralph D. Furmanek, Ballwin, MO (US);
Emerson Electric Co., St. Louis, MO (US);
Abstract
A method and device for driving a clothes washing machine motor at a predetermined speed is presented. The washing machine motor, which may be an AC induction motor, is powered by a DC to AC inverter that includes a DC bus. The DC bus current is measured and the inverter output frequency is adjusted in response to the DC bus current measurement. In exemplary embodiments, measuring the DC bus current includes measuring the voltage drop across a resistor coupled to the DC bus. The frequency adjustment may be calculated by multiplying the DC bus current by a compensation factor to calculate a frequency adjustment value. Alternatively, frequency adjustment values may be stored in a look-up table, and the measured DC bus current is used to index the look-up table.