When is a ceramic magnet used as a permanent magnet in a permanent magnet DC motor?
1
In motors rated in the range of 50 kW to 100 kW
2
In motors rated in the range of 100 kW to 150 kW
3
in fractional kW motor
4
In motors rated in the range of 10 kW to 50 kW
5
Question Not Attempted