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:
Aug. 05, 1997
Filed:
Mar. 09, 1995
Applicant:
Inventor:
Phillip G Langhorst, Crestwood, MO (US);
Assignee:
MagneTek, Inc., Nashville, TN (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
318716 ; 318254 ; 324177 ;
Abstract
The present invention provides a sensorless circuit for detecting rotational speed of a rotor in an induction motor. The circuit includes a switch between the AC source driving the motor and a motor phase winding. When the switch is closed, there is developed across the phase winding a voltage waveform from the AC source. When the switch is subsequently opened, there is developed across the winding a residual voltage waveform induced by the rotor. The speed of the motor is determined by measuring a time interval between selected points on the voltage waveform.