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 a synchronous motor and an induction motor?
The fundamental difference between these two motors is that the speed of the rotor relative to the speed of the stator is equal for synchronous motors, while the rotor speed in induction motors is less than its synchronous speed. … When the stator and rotor fields lock together, the motor is now synchronous.
What is the difference between the synchronous and asynchronous induction motors?
The synchronous motor is a type of AC motor that runs at synchronous speed. The asynchronous motor is a type of AC motor that runs on speed less than the synchronous speed. It operates on the principle of magnetic interlocking between rotor and stator field.
What are the advantages of synchronous motor over induction motors?
The advantages of the synchronous motor are the ease with which the power factor can be controlled and the constant rotational speed of the machine, irrespective of the applied load. Synchronous motors, however, are generally more expensive and a d.c. supply is a necessary feature of the rotor excitation.
Are synchronous motors AC or DC?
A synchronous electric motor is an AC electric motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current; the rotation period is exactly equal to an integral number of AC cycles.
Why induction motors are called asynchronous?
Because it runs at a speed less than synchronous speed. Because induction motor can not rotate at synchronous speed it always rotate less than synchronous speed. in short, induction motor never rotates at synchronous speed so it called asynchronous motor.
Is an induction motor AC or DC?
Induction motors, linear motors, and synchronous motors, for example, are all types of AC motors. AC motors can also include variable-frequency drives to control the motor’s speed and torque, while DC motors are available in self-excited and separately excited-type models.
Why is it called synchronous motor?
Definition: The motor which runs at synchronous speed is known as the synchronous motor. The synchronous speed is the constant speed at which the motor generates the electromotive force. The synchronous motor is used for converting the electrical energy into mechanical energy.
What is the function of induction motor?
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.
What are synchronous motors 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.
What is the disadvantage of synchronous motor?
Disadvantages or Demerits:
Synchronous motors requires dc excitation which must be supplied from external sources. Synchronous motors are inherently not self starting motors and needs some arrangement for its starting and synchronizing. The cost per kW output is generally higher than that of induction motors.
At what speed do synchronous motors run?
The 3-phase 4-pole (per phase) synchronous motor will rotate at 1800 rpm with 60 Hz power or 1500 rpm with 50 Hz power.
What is rotor speed?
Rotor speed depends, in part, on rotor diameter. Rotor speeds typically lie in the 120–210 m/s range, but mostly between 150 and 190 m/s, with a tendency to be higher with a smaller rotor diameter .
What is 3phase induction motor?
Three Phase AC Induction Motor. The three-phase AC induction motor is a rotating electric machine that is designed to operate on a three-phase supply. This 3 phase motor is also called as an asynchronous motor. … The principle of operation of this motor is based on the production of a rotating magnetic field.
Do synchronous motors have slip?
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. … Synchronous motor does not have slip. The value of slip is zero.