Difference Between Induction And Synchronous Motor Pdf

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An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. Three-phase squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable and economical. Single-phase induction motors are used extensively for smaller loads, such as household appliances like fans. Although traditionally used in fixed-speed service, induction motors are increasingly being used with variable-frequency drives VFD in variable-speed service. VFDs offer especially important energy savings opportunities for existing and prospective induction motors in variable-torque centrifugal fan, pump and compressor load applications.

Synchronous Motor : Types and Applications

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. A synchronous motor is a doubly excited machine, whereas an induction motor is a single excited machine.

In case of Synchronous motor its armature winding is energized from an AC source and its field winding from a DC source, whereas in case of Induction motor its stator winding is energized from an AC source.

An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor can therefore be made without electrical connections to the rotor. 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.

Therefore the rotor rotates at the same speed that of the rotating magnetic field. It is due to the reason the motor is called as synchronous motor. It is a constant speed motor because, despite the increase in load motor runs at the same synchronous speed. The main types are DC motors and AC motors, the former increasingly being displaced by the latter.

AC electric motors are either asynchronous or synchronous. Torque is the turning force through a radius — with the units Nm in the SI-system and the units lb ft in the imperial system. The torque developed by an asynchronous induction motor varies when the motor accelerates from zero to maximum operating speed. Electrical power plants almost always use synchronous generators because it is important to keep the frequency constant at which the generator is connected.

Low power applications include positioning machines, where high precision is required, and robot actuators. Mains synchronous motors are used for electric clocks. 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. Some of the typical applications of high speed synchronous motors are such drives as fans, blowers, dc generators, line shafts, centrifugal pumps, compressors, reciprocating pumps, rubber and paper mills. Synchronous motors are used to regulate the voltage at the end of transmission lines. For successful operation of alternator it must produce sinusoidal AC voltage at a particular frequency. Now, dc excitation produce a fixed polarity electromagnet in field which runs at a constant speed by the prime mover.

Thus it produce almost a sinusoidal AC by the stator armature. Starting of an Induction Motor. When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor starts rotating and the induction motor starts.

At the time of starting, the motor slip is unity, and the starting current is very large. Slip can be defined as the difference between the flux speed Ns and the rotor speed N. Speed of the rotor of an induction motor is always less than its synchronous speed.

A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. By reversing the current direction in the rotating windings each half turn, a steady rotating force torque is produced. Skip to content. Search for:.

Synchronous Motors vs. Induction Motors - What's the Difference?

Skip to Main Content. A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. Use of this web site signifies your agreement to the terms and conditions. This question is a common one, and the answer is not quite as simple as it may seem. Many factors must be taken into consideration, where the output rating is definitely one of those factors, but not the only one.

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Puranen Published Computer Science. Thesis for the degree of Doctor of Science Technology to be presented with due permission for the public examination and criticism in the Auditorium at High dynamic performance of an electric motor is a fundamental prerequisite in motion control applications, also known as servo drives. Expand Abstract.


rotor near to the synchronous speed. No starting mechanism is required in induction motors. ▫. The power factor of a synchronous motor can be adjusted.


Difference between Induction Motor and Synchronous 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. A synchronous motor is a doubly excited machine, whereas an induction motor is a single excited machine.

All rotary electric motors, ac, and dc, operate because of the interaction of two magnetic fields. Rotation is caused by the interaction between the two fields. In a simple dc motor, there is a rotating magnetic field whose polarity is reversed every half turn by means of a brush-commutator combination.

In the electrical systems, we use either in industries, power stations or domestic needs, motors and generators have become a common thing. With the demand for high energy efficient and less power consuming systems, the invention of new models of these electrical devices is seen. The basic calculating factor for motors and generators reliable operation is the Power factor.

Difference between Synchronous Motor and Induction Motor
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  1. Quirina A.

    PDF | On Oct 3, , Muhammad Umer Farooq published difference between induction motor and synchronous motor | Find, read and cite all the research you​.

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