The characteristics of motors vary widely with the nature of their application and the type of duty they are expected to perform. For example, the applications like constant speed, constant torque, variable speed, continuous/intermittent duty, steep/sudden starts, frequent start/stops, etc. should be taken into consideration carefully when deciding for the type of a motor for that specific application.
Following factors should be considered while selecting a drive for particular application:
Nature of electric supply
- Whether supply available is A.C. (single phase or three phase) or D.C. (pure D.C. or rectified A.C.)to be utilized for motor.
Nature of the drive
- Whether motor is to drive individual machine or a group of machines.
Nature of load
- Whether the load requires light or heavy starting torque.
- Whether load torque increases with speed or remains constant.
- Whether load has heavy inertia, which may required long starting time.
Electrical characteristics of motor
- Starting characteristics.
- Running characteristics.
- Speed control.
- Braking characteristics.
Size and rating of the motor
- whether motor is to run continuously intermittently or on load cycle.
- Whether over load capacity and pull torque are sufficient.
Mechanical considerations
- Type of enclosures.
- Type of bearings.
- Transmission of drive
- Noise level
Cost
- Capital cost.
- Running cost.
