Determination of an Induction Motor Rational Loading for Switching the Stator Windings Circuit

  • Sergey M. PLOTNIKOV
Keywords: induction motor, star circuit, delta circuit, constant losses, mechanical losses, additional losses

Abstract

Squirrel cage induction motors operating on a variable load and with a constant speed account for a large proportion of electric motors used in the industry. When running at partial load or in the idle mode, such motor has low efficiency and power factor. Under such conditions, its stator winding is switched over from the delta connection diagram, which is its normal circuit configuration, to the star circuit, at which the motor power reduces by a factor of three. However, the specific motor load at which this switchover should be carried out has not been defined in the current literature. The article considers the possibility of improving the squirrel cage induction motor efficiency by obtaining its maximum possible value in the delta and star schemes. The boundary power level at which the switchover from one scheme to another is performed is determined for a particular motor from the values of its losses in copper and steel, mechanical losses, and additional losses. The ratios of constant and variable losses of the motor connected according to the delta scheme to the losses of the motor connected according to the star scheme are obtained, and refined formulas for the boundary switching power are derived, which contain the values of three types of losses.

Author Biography

Sergey M. PLOTNIKOV

(Reshetnev Siberian State University of Science and Technology; Krasnoyarsk Institute of Railway Transport, Krasnoyarsk, Russia) – Professor of the of Informatics and Telecommunications Institute; Professor of the Systems for Ensuring the Movement of Trains Department, Dr.Sci. (Eng.), Docent

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Published
2023-08-31
Section
Article