Applications of AC and DC Motors

Applications of AC Motors:

1. Squirrel Cage Induction Motor: It is used in woodworking machines, laths, pumps, line shafts, presses, flour mills, small power shaft drives and printing machinery and whatnot. These motors are suitable for constant speed and small industrial drives at which speed control is not required essentially. It has low starting torque and constant speed characteristics.

2. Slip-ring Induction Motor: It is used in lifts, cranes, rolling mills, air compressors, sawmills, pumps winding machines, elevators, crushes, turn-tables, large capacity ventilation fans, stokers and whatnot. In these motors due to large starting torque and taking less current from the line. It is suitable where the starting load is very high. It has high starting torque and constant speed and can be made variable speed characteristics, if specially designed.

3. Synchronous Motor: It is used in power factor improvement, voltage regulation in a transmission line, to drive crushers of variable speed, ball mills and rotary kilns, vacuum pumps, blowers, line shafts, paper mills, rubber mills and centrifugal pumps, etc.

Applications of DC Motors:

1. Separately Excited DC Motor: It is used where a wide range of speed variation is needed that if from crawling speed to maximum speed is very accurate. It may also use steel rolling mills, paper making machines and ship propulsion in diesel electrical etc.

2. Shunt Motor: It is used where medium starting torque nearly constant speed and adjustable speed are needed. It can be used for fans, woodworking machines, lathes, centrifugal and reciprocating pumps, machine tools, blowers, printing presses, weaving and spinning machines of cotton mills and whatnot.

3. Series Motor: Series Motor is widely used where high starting torque, variation of speed needed, and momentary operating torque of maximum magnitude are deadly needed. It may be used for electric locomotives, trolley cars, conveyors, E.O.T cranes, hoists and elevators, etc.

4. Compound Motor: There are mainly two types of compound motor.

i. Cumulative Compound Motor: It is used where high starting torque and adjustable varying speed are needed. It may be used for bulldozers, heavy planers, air compressors, shears and punching machines, rolling mills, crushing machines, hoist elevators, heavy-duty light and big printing presses, etc.

ii. Differential Compound Motor: It is used where nearly constant speed and torque are needed. It is rarely used in practical fields for research and experimental jobs are needed.