Explain why induction motor is used everywhere in industry. Explain frequency control in induction And where it is used in textile industry.
Answers
Answer:
Induction motor is the horse power of the industry since long time ago.
Induction Motor is more used due to following reasons…
1) Induction motors have a simple construction.
2) Robust and Rugged.
3) Manufacturing Induction Motors cost is low compared to other motors.
4) Reliable operation in extreme condition.
5) Induction motors are durable.
6) Induction motor don't need an external exciting system they work directly on AC power(synchronous motors are doubly excited).
7) Self starting(synchronous motors are not self starting).
8) Low maintenance cost compared to other motors.
9) Induction Motors are very efficient, power losses are low.
10) Can be controlled by different means ( Speed control, Torque control, ...etc)
11) Though Speed control is better in case of DC motor(commutation problem) but due to certain other advantages, Induction motor is more popular.
12) Induction motor is a singly excited motor where as synchronous motor is a doubly excited one.synchronous motor need an additional dc source for excitation of rotor windings.
13) Induction motor is a self starting motor , where as synchronous is not a self starting motor , as rotor of synchronous motor must be rotated near to synchronous to get the magnetic coupling of rotor and stator.
14) Induction motor is cheaper when compared to synchronous motor.
15) The main requirement in industry is to operate motor at different loads and different speeds, to drive mechanical loads , so ,in this induction motor is the best to choose because it has so many types of speed control.where as synchronous motor always runs at synchronous speed.
16) Induction motor robust in construction and can work in any dusty environment .DC and sync cannot work in dusty and needs regular maintainence.
17) when coming to the efficiency , upper hand is for synchronous motor but the starting mechanism adds up extra cost , so even though less efficient induction motor are implemented.
18) Coming to dc motors and synchronous motor , these cannot work in harsh environments, where as induction motor can.
19) DC motors have brushes and synchronous motor have slip rings where induction motor(squirrel cage type)doesnt have , so reduced losses, efficient due to no frictional losses would be pesent.