Which motor is preferable?

Permanent Magnet DC Motor is Preferable:

• When the Required speeds exceed the linked to the network frequency.
• When a battery or accumulator power supply is required.
• When a high drive torque is required.
• When speed variation is required without resorting to expensive electronics.

Asynchronous AC Motor is Preferable:

• When fixed speeds determined by the frequency of power supply network can be used (e.g. 2800,1400,950 rpm)
• When higher speed stability is required.
• When an inverter can be fitted for continuous speed change.
• When the motor is exposed to heavy duty,thus reducing maintenance.