Monday, June 30, 2014
UNIVERSAL MOTOR;
CONSTRUCTION;
Universal motor can be operated either on ac and dc supply.the construcation of universal is same as that of dc series motor.the stator and rotor are made up of laminated silicon steel, to reduce eddy current and hysteresis loss,when the motor is operated on ac supply.the field winding is placed in the stator and the armature winding is housed in the rotor. the field winding has a few number of turns of turns t reduce the reactance.
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CONSTRUCTION;
Universal motor can be operated either on ac and dc supply.the construcation of universal is same as that of dc series motor.the stator and rotor are made up of laminated silicon steel, to reduce eddy current and hysteresis loss,when the motor is operated on ac supply.the field winding is placed in the stator and the armature winding is housed in the rotor. the field winding has a few number of turns of turns t reduce the reactance.
the field winding is connected in series with armature winding
OPERATION;
when the motor is connected to an ac supply,the same ac current fluxes through the field and armature winding.the field winding produces an alternating flux that reacts with the armature current and produces a torque.since both the armature current and field fluxes are reversed simultaneously,the torque always in the same direction.
CHARACTERISTICS;
the speed torque characteristics of universal motor are similar to that of dc series motor.
the speed increases with decreasing of load.at no load the speed of the motor is very high.however in a dc series motor the speed at no load is dangerously high value.
ADVANTAGES;
1.it is speed is high
2.ac and dc supply will be working
3.starting torque is high
APPLICATION;
1.vacuum cleaners
2.sewing machine
3.food mixers
4.machine tools
5.portable drilling machines
DISADVATAGES;
1.the speed at no load is dangerously high value.
