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:
Nov. 16, 1993
Filed:
Nov. 02, 1992
James B Farr, Ann Arbor, MI (US);
Tecumseh Products Company, Tecumseh, MI (US);
Abstract
The present invention is an inverter for a portable refrigerator. The inverter includes a square wave generator operable by a DC voltage source. A timer is also included which, in conjunction with the square wave generator, provides a multiple phase waveform for operating a compressor motor. For conventional three winding compressor motors, the inverter provides a six-step waveform for operation of the portable refrigerator. The inverter can also drive the motor using either a first or second DC voltage level, by minor changes in the inverter and using either a wye or delta winding configuration. The inverter also includes a protection circuit which protects against locked rotor and overload current conditions, as well as a shut-off circuit to guard against operating at low speeds and completely draining the battery.