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.

Energy efficient motors

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.