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Sysnchronus Motors have constant magnetic field in the rotor these cannot use induction windings for starting. These motors require a variable-frequency power source to start. The main difference between a permanent magnet synchronous motor and an asynchronous motor is the rotor
Synchronous motor always runs at a speed equal to its synchronous speed i.e speed of rotation of magnetic field of stator.Induction motor always runs at a speed which is less than the synchronous speed.
Synchronous motor always runs at a speed equal to its synchronous speed.Induction motor always runs at a speed which is less than the synchronous speed.
All induction motors are asynchronous motors. The asynchronous nature of induction-motor operation comes from the slip between the rotational speed of the stator field and somewhat slower speed of the rotor. A more-specific explanation of how this slip arises gets into details of the motor internals.
A synchronous motor runs at a speed which is synchronised to the frequency of the AC voltage that supplies it, i.e the rotor and stator run at the same speed.
but An asynchronous motor generally runs rotor slower than the stator.there is a slip resulting from different losses(copper,iron,friction,air gap,...etc.) for examle
3-phase induction motor
A synchronous motor has a special rotor construction that lets it rotate at the same speed — that is, in synchronization — with the stator field.
AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.called asynchronous motor.
synchronous motor drive in constant speed ,but asynchronous motor decrees some speed with load variation
a)The self-energized synchronous engine, additionally called an exchanged hesitance engine, contains a rotor cast of steel that incorporates indents or teeth, named remarkable shafts. It is the indents that let the rotor lock in and keep running at the same pace as the pivoting attractive field.
b)asynchronous motor run slower than the above with the rate that normally changes
a synchronous motor run at a speed which is synchronised to frequency of ac voltage supplied to it ex: motor is supplied at frequency 60 hz then it will run at 603020 etc rev/sec depend on number of magnetic pole (246)
a asynchronous motor run slower than the above with the speed that usually varies