What are energy efficient motors

Energy efficient motors

  • Energy efficient motors are motors in which improvements in the design are assimilated so as to increase the efficiency more than the standard motor.
  • Design improvements in energy efficient motors mainly target reduction in inherent motor losses.

Each loss is addressed specifically by adopting some measures as follows:

Stator Cu loss:

  • Selection of a proper size of the copper conductor so as to reduce its resistance.
  • Mostly the copper cross section of winding wires is preferred to increase which decreases resistance and hence I2R losses.

Rotors Cu losses :

  • Increasing the section of rotor bars and rings, rotor copper losses can be reduced through weight increase.
  • Use of copper conductors in rotor causes less winding resistances comparatively.
  • Synchronous speed operation of the motor also reduces I2R loss.

Core losses :

  • To reduce hysteresis loss use of low loss grade silicon steel, the modest increase in stator and rotor core length.
  • To reduce eddy current use of thinner laminations.

Friction and windage losses:

  • Better fan design is adopted.
  • Use of improved and proper bearings.
  • Improvement in aerodynamic design of rotor and facilitation of airflow.

Stray load losses

  • These can be reduced by better electromagnetic design of slots and windings by careful selection of slots and windings by careful selection of :
  1. All gap length
  2. Number of slots
  3. Tooth per slot geometry
  • These modification incorporated in to improve efficiency uses more and better material, makes energy efficient motors expensive as compared to standard motors.

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