induction motor1

8-Dec-11T.S.L.V.Ayyarao

GMR INSTITUTE OF TECHNOLOGY

INDUCTION MOTOR

Unit-V



AC Machines

• Three-Phase Induction Motors. • Synchronous Machines. • Single-Phase Motors. • Stepper and Brushless DC Motors.



INDUCTION MOTOR

ADVANTAGES:• 3-phase induction motors

are simple & rugged.• Its cost is low & it is

reliable• Its has high efficiency.• Its maintenance cost is

low• Its is self starting motor• Suitable for all

environments like coal mines & chemical factories



Construction



Construction

A 3-phase induction motor has two main parts1.Stator– Rotor

StatorThe stator core is a stack ofcylindrical steel laminations.Slots are punched to receivethe winding.The stator carries 3phaseWinding.



Construction

• Three windings are space displaced by 1200 electrical.

• Large size motors use open slots.• Small size motors use semi closed slots.• The air gap length should be as small as

possible



Construction

The stator winding for a definite number of poles.Greater the poles, lesser the speed and vice versa.Rotor1.Squirrel-cage rotor– Phase-wound rotor



Construction

Squirrel-Cage Rotor



Construction

Squirrel-cage rotor• The rotor winding is in form of copper bars.• The copper bars are revited, welded with end

rings.• No external resistance can be inserted in the

rotor circuit.



Construction

Wound rotor• The rotor winding is uniformly distributed..• Three leads are connected to the slip rings.• Carbon brushes are pressed on the slip rings.



Construction

Phase-wound Rotor



Construction

induction motor1

Business

phase induction

slip rings

wound rotor8

copper bars

ayyaraogmr

technologyconstruction8

technologyconstructionsquirrel

poles