If the excitation of a synchronous motor is kept constant, the load current changes with the variation of load. If the load is kept constant and field excitation is varied, the synchronous motor operates by changing its power factor. When the excitation is weak. the stator takes a magnetising current from 3 phase AC supply

When the excitation of a three phase synchronous motor taking constant power P from constant voltage supply main is varied, the power factor of the motor changes. The power drawn by a 3 phase synchronous motor is given by, P = √3 VI cosΦ where V is the line voltage, I is the armature current

The four various types of torque associated with a synchronous motor are described below. Four types of torque are, Starting torque It indicates the ability of the motor to accelerate the load. It is also sometimes called “break away torque”. It may be as low as 10% in case of centrifugal pumps, and as high

The armature winding of an alternator is distributed over the entire armature. The distributed winding produces nearly a sine waveform and heating is more uniform. Likewise, the coils of armature winding are not full-pitched, the two sides of a coil are not at corresponding points under adjacent poles. The fractional pitched armature winding requires less

An alternator has 3 phase winding on the stator and D.C field winding on the rotor. Stator It is the stationary part of the machine and is built up of sheet-steel laminations having slots, on its inner periphery. A 3 phase winding is placed in these slots and serves. as the armature winding of the

The machine which produces 3 phase power from mechanical power is called an alternator or synchronous generator. An alternator works on the same fundamental principle of electromagnetic induction as a D.C generator, when the flux linking a conductor changes, an emf is induced in the conductor. Like a D.C generator, an alternator also has an

The stator winding of a single phase induction motor is connected to single phase AC supply. Then a magnetic field is developed in the stator whose axis is always along the axis of stator windings. With alternating current in the fixed stator coil the mmf wave is stationary in space but pulsates in magnitude and

The single phase induction motors are small motors. These motors have power rating in fractional horse power range. These motors are used in homes, offices, shops and factories. They provide motive power for fans, washing machines, hand tools like, drillers, record player, refrigerators, juice makers etc. The single phase motors are simple in construction. The