What are the classes of AC motors?

What are the classes of AC motors?  
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1 Answer

Answer :

Depends on phases

a. 1φ.

b. 3φ.

Depends on construction

a. Squirrel cage induction motor for fixed torque.

b. Wound rotor motor for variable torque.

Depends on voltage

a. LT motor - <200 kW.

b. HT motor - >200 kW.

Depends on torque and current

a. Class – A (Normal torque and normal starting current. E.g. Fractional motors.) .

b. Class – B (Normal torque and low starting current).

c. Class – C (High starting torque and low starting current. E.g. Double sq. cage motor)

d. Class – D (high starting torque and high starting current).

Depends on mechanical characteristics

a. Drip proof (IP 54). Safety against water or dust.

b. Splash proof.

c. TEFC (totally enclosed fan cooled).

d. TEOV (totally enclosed open ventilated).

e. TETV (totally enclosed tube ventilated. Principle is thermosymphony E.g. - CEP).

f. Explosion proof. 
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