Advangates And DisadvangatesOf AC Motors Over Others

There are so many advantages and disadvantages of Alternative Current Induction motor over other types of motors. Before we go deep in to advantages and disadvantages of AC Induction motors we will check about what are the types of motors available in electrical industry.

Ac Motors divide in to Synchronous Motors and Induction motor and then Induction motors divide in to Single phase and Three Phase motor. In here we will see what are the advantages and disadvantages of AC motors over DC and Special motors.


ADVANTAGES OF AC MOTORS

Simple Design

A series of three windings in the stator section with a simple rotating section rotor. The changing field caused by the 50 or 60 Hz This type of Ac motor winding are easy to maintain and design.

Low Cost

The AC motor has the advantage of being the lowest cost motor for applications requiring more than about 1/2 hp (325 watts) of power. This is due to the simple design of the motor. And by compare to other type of motors such as DC motor’s this type of motors are very cheap.

Reliable Operation

This indicates how AC (Auxiliary Current )motors are Reliable than other type of motors such as DC ( Direct Current ) motors.

•    AC motors are in extremely reliable
•    Low maintenance operation.
•    There are no brushes to replace.
•    AC motor can expect to need new bearings after several years of operation.
•    If the application is well designed

DISADVANTAGES OF AC MOTORS

Expensive speed control

Speed control is expensive and the electronics required to handle an AC inverter are considerably more expensive AC inverters and AC motors are usually more cost-effective than DC motors and DC drives for applications larger than about 10 horsepower, because of cost savings in the AC motor.

Poor positioning control

Positioning control is expensive and crude. Even a vector drive is very crude when controlling a standard AC motor.

High starting current

Squirrel cage motors suffer from drawing high starting current (some 6-8 times full load current) so I2R losses at starting are much greater than the full load. Lengthy starting periods thus cause early failure. Direct on -line (DOL) starting is usually the more favored. I have mentions some motor starting methods in motor controlling section of this report.