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U.S. Department of Energy
Office of Scientific and Technical Information

Method and apparatus for monitoring the rotating frequency of de-energized induction motors

Patent ·
OSTI ID:570427
The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor. 6 figs.
Sponsoring Organization:
USDOE, Washington, DC (United States)
Assignee:
Dept. of Energy, Washington, DC (United States)
Patent Number(s):
US 5,714,862/A/
Application Number:
PAN: 8-649,974
OSTI ID:
570427
Country of Publication:
United States
Language:
English