Table of Contents
What do you mean by synchronous motor?
A synchronous motor is one in which the rotor normally rotates at the same speed as the revolving field in the machine. The stator is similar to that of an induction machine consisting of a cylindrical iron frame with windings, usually three-phase, located in slots around the inner periphery.
What is a synchronous motor and how does it work?
Methods of Starting of Synchronous Motor Synchronous motors are mechanically coupled with another motor. It could be either 3 phase induction motor or DC shunt motor. DC excitation is not fed initially. It is rotated at speed very close to its synchronous speed and after that DC excitation is given.
Why is it called synchronous motor?
1.2 Synchronous Motors Synchronous motors, as the name implies, rotate at a constant (synchronous) speed. The rotor of this type of motor is a wound rotor, which receives the excitation (magnetizing) current from its excitation system (a separate direct current source with controller).
Where is synchronous motor used?
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.
What are the main characteristics of synchronous motors?
Main Features of Synchronous Motors Synchronous motors are inherently not self starting. The speed of operation of is in synchronism with the supply frequency and hence for constant supply frequency they behave as constant speed motor irrespective of load condition.
What are the main parts of synchronous motor?
The Construction of Synchronous Motors A synchronous motor is generally made up of two parts, a stator the stationary part of the machine that carries the armature winding in which the voltage is generated, and a rotor the rotating part of the machine that produces the main field flux.
How does a synchronous motor start?
The motor is first started as a slip ring induction motor. The resistance is gradually cut-off as the motor gains speed. When it achieves near synchronous speed, DC excitation is given to the rotor, and it is pulled into synchronism. Then it starts rotating as a synchronous motor.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.
How can synchronous motor be stopped?
The methods that are employed for Braking of Synchronous Motor are: Regenerative braking while operating on a variable frequency supply. Rheostatic braking. Plugging.
What is the advantage of synchronous motor?
The advantage of using synchronous motor is the ability to control the power factor. An over excited synchronous-motor has leading power factor and is operated in parallel to induction motors thereby improving the system power factor. Speed remains constant irrespective of the loads in synchronous motors.
What is the function of synchronous motor?
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.
What is difference between synchronous and asynchronous motor?
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. AC Induction Motor is known as the Asynchronous Motor. Synchronous motor does not have slip.
What is the difference between synchronous motor and generator?
Synchronous Motor: The main difference between the two is the sign conventions. Current reference is out of the plus terminal of the generator, but into the plus terminal of the motor. This leads to different diagrams for various DC excitations of the field as shown below.
What are the benefits of synchronous motor in real world application?
usually, synchronous motors are used for applications where precise and constant speed is required. Low power applications of these motors include positioning machines. These are also applied in robot actuators. Ball mills, clocks, record player turntables also make use of synchronous motors.
What are the different types of motors?
Types of Electric Motors 1). DC Shunt Motor. 2). Separately Excited Motor. 3). DC Series Motor. 4). PMDC Motor. 5). DC Compound Motor. 1). Synchronous Motor. 2). Induction Motor. 1). Stepper Motor.
What are types of synchronous motor?
Synchronous motors can be classified into two types based on how the rotor is magnetized.This type of synchronous motor is divided into three categories and is available in three designs, each of which has unique features: Hysteresis Synchronous Motors. Reluctance Synchronous Motors. Permanent Magnet Synchronous Motors.
Why the speed of synchronous motor is constant?
Synchronous motors are constant speed motors. They run at the synchronous speed of the supply. As you can see, the synchronous speed depends on the frequency of the supply and the number of poles of the rotor. Changing the number of poles is not easy, so we do not use that method.
What are the two types of synchronous generators?
Types of synchronous machines Hydrogenerators : The generators which are driven by hydraulic turbines are called hydrogenerators. These are run at lower speeds less than 1000 rpm. Turbogenerators: These are the generators driven by steam turbines. Engine driven Generators: These are driven by IC engines.
What is meant by synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What is the principle of synchronous generator?
The principle of operation of synchronous generator is electromagnetic induction. If there exits a relative motion between the flux and conductors, then an emf is induced in the conductors.
