The synchronous motor is made self starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate, therefore, in the beginning synchronous motor provided with damper winding starts as a squirrel cage induction motor. The exciter moves along the rotor. When the motor attains about 95%of synchronous speed, the rotor winding is connected to exciter terminals and the rotor is magnetically locked by the rotating field of the stator and the motor runs as a synchronous motor. While starting a synchronous motor, the field winding must be shorted through a suitable resistance so that the induced voltage is distributed throughout the whole winding and no part is subjected to the high voltage induced in the entire winding.
A single-phase induction motor has a main winding and a starting winding. When the motor has run up to normal speed the starting winding can be switched out, but for small motors this is not usually worth the trouble.
explain wound rotor
its impossible to give suppy to rotor of an induction motor,because of it a closed path for circulating currents.
simply saying u that field winding is a winding present at the stator of the motor and is used to produce the magnetic field and the armature winding is the winding present in the rotor and is used to rotate the shaft of the motor. there are some machines with permanent magnets, those permanent magnets are used as the major source of magnetic flux in the machine instead of the field winding .
Standard induction motor has a closed squirrel cage rotor, where as open ended induction motor has split phase rotor.
Squirrel cage induction motors.
This is how an induction motor normally works, hence the name. The supply voltage is connected to the stator winding(s) and a current is induced in the rotor. A synchronous motor, on the other hand, will have current supplied to the rotor through slip rings and brushes. The rotor current is generally supplied as DC though, or else rectified in the rotor.
just put a auxilari winding on the rotor (in the salient pole)..
Like transformer induction motor has stator winding(Primary winding) and rotor winding(Secondary winding) separated by an airgap.Rotor winding(generally Al bars) are short circuited at the end to produce torque for the rotation.Hence the name short circuited transformer.
An induction motor consists of a rotor winding and stator winding. Rotor windings are short circuited and stator winding are given electrical AC supply .Now lets do the physics behind it . As the current starts to flow in the stator winding , magnetic flux start to produce around it . due to it's alternating nature that flux varies and according to farady law emf is induced in the rotor winding .Since the rotor winding is short circuited the current circulates in it .And when a current carrying conductor is placed in magnetic field it experiances a force and hence if start to rotate.
The synchronous motor is made self starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate, therefore, in the beginning synchronous motor provided with damper winding starts as a squirrel cage induction motor. The exciter moves along the rotor. When the motor attains about 95%of synchronous speed, the rotor winding is connected to exciter terminals and the rotor is magnetically locked by the rotating field of the stator and the motor runs as a synchronous motor. While starting a synchronous motor, the field winding must be shorted through a suitable resistance so that the induced voltage is distributed throughout the whole winding and no part is subjected to the high voltage induced in the entire winding.
AC motor has two main winding components - stator and a rotor. Stator winding is stationary where as rotor winding is on rotating part.
A single-phase induction motor has a main winding and a starting winding. When the motor has run up to normal speed the starting winding can be switched out, but for small motors this is not usually worth the trouble.
A transformers main function is to change one voltage to another voltage. A motors main function is to relieve man of tedious and repetitive work and also work that man has not the strength to do alone.Another AnswerAlthough, as outlined in the first answer, they have completely different functions transformers and induction motors do in fact have certain similarities.They each have a primary winding and a secondary winding (although, in the case of the motor, they are termed the 'field winding' and the 'rotor winding'), and voltages are induced into the motor's rotor winding by 'transformer action'.The main difference, of course, is that the motor's 'secondary winding' (the rotor) is not fixed, but rotates. This means that the frequency of the currents in the rotor change as the rotor's speed changes: being equal to that of the 'primary winding' (field winding) at standstill, but reducing as the rotor speeds up and approaches synchronous speed. Mathematically, both are treated in a very similar manner, with their equivalent circuits being practically identical, although the 'no load' current (i.e. when the rotor is stationary) of a motor is significantly higher than a transformer's due to the much higher leakage reactance caused by the air gap between the stator and the rotor.
Induction motor is an AC electric motor which uses electromagnetic induction to induce the electric current in the rotor to produce torque.
A single-phase induction motor has a main winding and a starting winding. When the motor has run up to normal speed the starting winding can be switched out, but for small motors this is not usually worth the trouble.