- Even if the machine is lossless we cannot ignore the electrical portion of airgap power which
- When we subtract friction and windage losses from the developed power then we obtain the shaft power.
- In Induction machine we do not merge core loss and mechanical loss as rotational loss because there location inside the machine is different and hence both cannot be directly added.
- Core loss
- Bearing friction loss
- Brush friction loss
- Windage loss
- In Squirrel Cage Induction Motor (SCIM) we do not use of a brushes so brush friction loss does not appear in SCIM.
- Stator Copper (Cu) loss
- Rotor Copper (Cu) loss
- Brush Contact Drop (SRIM) (Slip Ring Induction Motor)
- Stray load loss.
- While computing the efficiency we made to consider the brush contact drop but in the condition of maximum efficiency brush contact drop does not appear.
- To reduce the bearing friction we make use of lubricant such as grease in small induction motor and lube oil in large Induction motor.
- Lube oil will also act as a coolant.
- Windage loss depends on air gap and since airgap is higher in SRIM so windage loss of SRIM is higher then SCIM.