What is meant by synchronous machines?

A synchronous machine is an electrical machine whose rotating speed is proportional to the frequency of the alternating current supply and independent of the load.

What are synchronous machines used for?

Synchronous motors are normally used in applications in which a constant and precise speed is required. Typical applications of these low power motors are positioning machines. They are also used in robot actuators. Synchronous motors are also used in ball mills, watches, record players, and turntables.

How does a synchronous machine work?

The operation of a synchronous motor is due to the interaction of the magnetic fields of the stator and the rotor. The rotor locks in with the rotating magnetic field and rotates along with it. Once the rotor field locks in with the rotating magnetic field, the motor is said to be in synchronization.

Why it is called synchronous machine?

A synchronous generator is called “synchronous” because the waveform of the generated voltage is synchronized with the rotation of the generator. Each peak of the sinusoidal waveform corresponds to a physical position of the rotor. The magnetic field of the rotor is supplied by direct current or permanent magnets.

What is the difference between synchronous and asynchronous machine?

Synchronous motor is a machine whose rotor speed and the speed of the stator magnetic field is equal. Asynchronous motor is a machine whose rotor rotates at the speed less than the synchronous speed. Asynchronous motor does not require any additional starting source.

What is the basic principle of synchronous machine?

The principle of operation of a synchronous motor can be understood by considering the stator windings to be connected to a three-phase alternating-current supply. The effect of the stator current is to establish a magnetic field rotating at 120 f/p revolutions per minute for a frequency of f hertz and for p poles.

What is ID and IQ currents?

where id, iq are the armature current vector of d-axis and q-axis, respectively. Ud, Uq are the voltage vectors of d-axis and q-axis, respectively. icd, icq are the iron loss current of d-axis and q-axis, respectively.

What is slip of motor?

“Slip” in an AC induction motor is defined as: As the speed of the rotor drops below the stator speed, or synchronous speed, the rotation rate of the magnetic field in the rotor increases, inducing more current in the rotor’s windings and creating more torque. Slip is required to produce torque.

What is difference between induction and synchronous machines?

Synchronous motors require an additional DC power source for energizing rotor winding. Induction motors do not require any additional power source. Synchronous motors require additional starting mechanism to initially rotate the rotor near to the synchronous speed. No starting mechanism is required in induction motors.

What is the difference between induction machine and synchronous machine?

The induction motor has self-starting torque whereas the synchronous motor is not self starting. It has to be run up to synchronous speed by any means before it can be synchronized to AC supply. A synchronous motor can be operated with lagging and leading power by changing its excitation.

What is damper winding?

: a short-circuited squirrel-cage winding placed in the pole faces and around the pole shoes of synchronous machines, the currents induced in the winding by the periodic variations in synchronous speed having the effect of a damper. — called also amortisseur.