Synchronous Motors: Applications, Starting Methods & Working Principle

Electrical motors are an electro-mechanical device that converts electrical energy to mechanical energy. Based on the type of input we have classified it into single phase and 3 phase motors. The most common type of 3 phase motors are synchronous motors and induction motors. When three-phase electric conductors are placed in certain geometrical positions (i.e. … Read more

Rotating Magnetic Field

When we apply a three-phase supply to a three-phase distributed winding of a rotating machine, a rotating magnetic field is produced which rotates in synchronous speed. In this article, we will try to understand the theory behind the production of rotating magnetic field. For that, we will first imagine one stator of an electric motor … Read more

Model Diagram of Synchronous Motor

V = Terminal voltage Re = Effective resistance XL = Leakage reactance Xa = Fictious reactance Xs = Synchronous reactance E = Counter emf In case of synchronous motor revolving field structure is to be energized by direct current. In stator winding two effects are to be considered the effect of field cutting stator conductors … Read more

Synchronous Motor Starting

Synchronous motors run at synchronous speed. The synchronous speed of a motor depends on the supply frequency and the number of poles in the motor. Synchronous speed is given by Where, f = supply frequency and p = number of poles. We can change the synchronous speed of the motor by changing the supply frequency … Read more

Construction of Synchronous Motor

Synchronous motors run at synchronous speed. The synchronous speed is given by Where, Ns = synchronous speed, f = supply frequency and p = number of poles. As we can see from the equation, the synchronous speed depends on the frequency of the supply and the number of poles. The construction of a synchronous motor … Read more

Speed Control of Synchronous Motor

Synchronous motors are constant speed motors. They run at the synchronous speed of the supply. They are generally used for constant speed operation under no load conditions such as to improve the power factor. Synchronous motors have fewer losses than induction motors at a given rating. The speed of a synchronous motor is given by … Read more

Types of Synchronous Motor

There are different types of synchronous motors based on the way they are excited Non Excited Synchronous Motors Current Excited Synchronous Motors Let us take a look at the different types one by one. Non Excited Synchronous Motor The rotor is made up of steel. The external magnetic field magnetises the rotor, and it rotates … Read more

Phasor Diagram for Synchronous Motor

We will discuss here the simplest way of drawing the phasor diagram for synchronous motor and we will also discuss advantages of drawing the phasor diagram. Before we draw phasor diagram, let us write the various notations for each quantity at one place. Here we will use: Ef to represent the excitation voltage Vt to … Read more

Excitation Control of Synchronous Machine Using Chopper

Synchronous machine is a versatile electric machine which uses in various field like its use to generate power at the generating stations, for constant speed, power factor correction etc. Power factor control of synchronous machine is done by controlling DC field excitation of it. Our thesis is based on it that how efficiently we can … Read more

Synchronous Motor Excitation

Prior to understanding this synchronous motor excitation, it should be remembered that any electromagnetic device must draw a magnetizing current from the AC source to produce the required working flux. This magnetizing current lags by almost 90o to the supply voltage. In other words, the function of this magnetizing current or lagging VA drawn by … Read more