Monday, June 30, 2014
REPULSION INDUCTION MOTOR
construction;
THIS motor is a combination of repulsion and induction motor.the stator of this is made with non salient pole with single phase winding.
THE rotor is provided with two separate windings in common slots.one winding is armature winding with commutator and short circuited brushes (just like dc motor) the other winding is of squirrel cage type.the inner winding is a squirrel cage winding and the outer winding is commutated winding.repulsion induction motor the reactance
of the squirrel cage winding is very high.
working;
at the time of starting the frequency of rotor emf is more
(f=sf at starting slip (s)=1).hence the reactance of inner cage winding is high XL.therfore very little current flows through
the inner cage winding.when the rotor picks up speed the frequency
of the rotor emf is reduced and therefore the reactance of the rotor
will decrease now the squirrel cage winding takes up a larger portion of the current.
the brushes are short circuited and ride on the commutator continuously.the speed torque characteristics of repulsion inducation motor.the starting torque is high.the speed regulation is also good.
it can develop torque sudden heavy loads.
APPLICATION;
1.it is used to drive compressors.
2.petrol pumps
3.air pump
4.mixing machines
5.machine tools
6.hoists
ADVANTAGES;
1.starting torque high
2.speed regulation good
3.it can develop torque sudden heavy loads
4.starting current reduced
construction;
THIS motor is a combination of repulsion and induction motor.the stator of this is made with non salient pole with single phase winding.
THE rotor is provided with two separate windings in common slots.one winding is armature winding with commutator and short circuited brushes (just like dc motor) the other winding is of squirrel cage type.the inner winding is a squirrel cage winding and the outer winding is commutated winding.repulsion induction motor the reactance
of the squirrel cage winding is very high.
working;
at the time of starting the frequency of rotor emf is more
(f=sf at starting slip (s)=1).hence the reactance of inner cage winding is high XL.therfore very little current flows through
the inner cage winding.when the rotor picks up speed the frequency
of the rotor emf is reduced and therefore the reactance of the rotor
will decrease now the squirrel cage winding takes up a larger portion of the current.
the brushes are short circuited and ride on the commutator continuously.the speed torque characteristics of repulsion inducation motor.the starting torque is high.the speed regulation is also good.
it can develop torque sudden heavy loads.
APPLICATION;
1.it is used to drive compressors.
2.petrol pumps
3.air pump
4.mixing machines
5.machine tools
6.hoists
ADVANTAGES;
1.starting torque high
2.speed regulation good
3.it can develop torque sudden heavy loads
4.starting current reduced
