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:
Oct. 12, 1993
Filed:
Dec. 10, 1987
Frank E Wills, York, PA (US);
Jacob E Shaffer, Jr, York, PA (US);
York International Corporation, York, PA (US);
Abstract
By employing a single phase pulse width modulated inverter system, a-c power line voltage may be effectively converted to single phase, variable amplitude and frequency sinusoidal voltage for driving a single phase a-c induction motor at an adjustable speed. The motor may be driven directly in response to the power line voltage (such as during start-up or when it is desired to run the motor at the power line frequency) by bypassing the inverter system and connecting the motor across the power line. Reduced energy consumption may be obtained by operating the motor in response to a reduced inverter output frequency. Switching the motor from the power line to the inverter, and vice versa, is accomplished without interruption. Immediately prior to each, switchover the inverter output voltage is synchronized to the power line voltage to minimize any electrical disturbance during the switching transition.