Energy saving operation of induction motors by voltage reduction at no and low partial-load

An investigation of the electrical energy savings obtained by reducing the terminal voltage of induction motors when they are not loaded or only partially loaded is presented. The purpose is to obtain information to help decide whether to install an energy saving device in plants using induction motors. At no-load operation, the saving can be as high as 50%. The saving decreases with the increase of load. Switching-off one phase of the three-phase supply during no-load operation does not contribute to energy saving. Intermittent disconnection of the supply voltage can lead to considerable energy saving, if the interruption interval is sufficiently long. This method is recommended for small motors.<
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