What is the purpose of synchronous machine?

In higher power industrial sizes, the synchronous motor provides two important functions. First, it is a highly efficient means of converting AC energy to work. Second, it can operate at leading or unity power factor and thereby provide power-factor correction.

Why do we need synchronous generator?

G’s for generation of electric power we will have severe active and reactive power issues and hence voltage will have imbalance. … Hence Synchronous Generator is used to supply power which are mainly large generation units like thermal, hydro, nuclear and Gas power plant etc.

Why we use only synchronous motor as a generator?

Essentially, either winding can provide exciting current for the machine, which means the power factor of the motor can be varied by controlling the field current. Thus, one of the traditional reasons for using a synchronous motor is to provide power factor correction.

What is the application of synchronous generator?

Synchronous generators are the majority source of commercial electrical energy. They are commonly used to convert the mechanical power output of steam turbines, gas turbines, reciprocating engines and hydro turbines into electrical power for the grid. Some designs of Wind turbines also use this generator type.

Why are synchronous machines called synchronous?

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.

Why it is called synchronous machine?

Synchronous motors are so called because they operate at only one speed, i.e. the speed of the rotating field. The mechanical construction is exactly the same as the alternator shown in Figure 2.47.

How do synchronous generators work?

In a synchronous generator, a DC current is applied to the rotor winding producing a rotor magnetic field. The rotor is then turned by external means producing a rotating magnetic field, which induces a 3-phase voltage within the stator winding. The rotor of a synchronous machine is a large electromagnet.

What is the difference between synchronous and induction generator?

Difference between synchronous generator and induction generator. In a synchronous generator, the waveform of generated voltage is synchronized with (directly corresponds to) the rotor speed. … Induction generator takes reactive power from the power system for field excitation.

What is synchronous machine?

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 is the 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 synchronous In synchronous machine?

A synchronous motor (short for synchronous electric motor) is an AC motor where the rotation of the rotor (or shaft) is synchronized with the frequency of the supply current. That is, the rotation period of the rotor is equal to the rotating field of the machine it is inside of.

How does synchronous motor improve power factor?

A Synchronous Motor can be made to operate at unity and leading power factor by just increasing its excitation voltage i.e. by increasing the field current. This advantage of Synchronous Motor is used to improve the power factor. … Hence, Power Factor = CosƟ = Cos0 = 1.

Why DC supply is used in synchronous motor?

for a synchronous motor we give balanced 3 phase supply to the stator which produces a rotating magnetic field.in order to produce torque we need another magnetic field which has to be relatively stationary with respect to the main field. this feild is produced on rotor winding by energising it with dc.

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.

Why synchronous motor is a variable power factor motor?

Synchronous motors are designed to operate at unity (1.0) power factor or 0.8 leading power factor. By varying the DC excitation of the motor, the power factor of the motor can be varied widely. … This yields an improved power factor for the power-supply system.

Do synchronous motors have slip?

The difference between the synchronous speed of the electric motor magnetic field, and the shaft rotating speed is slip – measured in RPM or frequency.

What is floating in synchronous machine?

A synchronous motor is said to be ‘floating’ when it operates at no load and without losses.

Why are synchronous motors more efficient?

Synchronous motors generally have a higher power density than induction motors of comparable size, allowing them to provide more power at a smaller volume.

Why synchronous motor is a constant speed motor?

Synchronous motor works on the principle of force developed due to the magnetic attraction established between the rotating magnetic field and the main pole feed. Since the speed of rotating magnetic field is directly proportional to frequency the motor operates at constant speed.

Why synchronous generator is doubly excited?

A synchronous machine is called a doubly excited machine because both its rotor and stator are excited. To achieve magnetic locking between stator and rotor, double excitation needed. The stator of 3 phase synchronous motor is excited with a 3-phase supply while rotor is with DC Supply.