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Title: Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

Abstract

The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

Inventors:
 [1];  [2]
  1. (Brighton, MI)
  2. (Livonia, MI)
Publication Date:
Research Org.:
EATON CORP
OSTI Identifier:
868163
Patent Number(s):
US 5086264
Assignee:
Eaton Corporation (Cleveland, OH) OSTI
DOE Contract Number:  
AC07-84NV10366
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
motor; torque; compensation; induction; electric; adjusting; slip; command; periods; supposed; change; temperature; maintains; constant; inverter; driven; variations; rotor; output; dependent; temperatures; nominal; operating; condition; impedance; increases; reducing; current; similar; fashion; reduced; resulting; increased; monitors; bus; dc; supply; adjusts; frequency; drive; maintain; adjustment; based; predetermined; conditions; implying; decreased; exist; interval; time; slip frequency; induction motor; electric motor; operating condition; motor torque; torque output; dc supply; predetermined interval; maintains constant; constant torque; /318/

Citation Formats

Kelledes, William L., and St. John, Don K. Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature. United States: N. p., 1992. Web.
Kelledes, William L., & St. John, Don K. Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature. United States.
Kelledes, William L., and St. John, Don K. Wed . "Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature". United States. https://www.osti.gov/servlets/purl/868163.
@article{osti_868163,
title = {Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature},
author = {Kelledes, William L. and St. John, Don K.},
abstractNote = {The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {1}
}

Patent:

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