0
A synchronous motor aways runs at the synchronous speed, which is the supply frequency divided by the number of pairs of poles in the motor.
For a 4-pole motor the speed is 1500 rpm (50 Hz supply) or 1800 rpm (60 Hz supply).
The mechanical phase of the rotor is liable to be a little unstable under changing load conditions.
Add your answer:
Earn +20 pts
Why the DC motor is call as synchronous motor?
A 60Hz synchronous motor spins at synchronous speed - if it's a two pole motor it will spin at exactly 1800 rpms. An asynchronous motor will spin at a speed lower than the power supply frequency - a symilar asynchronous motor may spin at 1700 rpms.
Why does the rotation of the motor reversed when change the polarity across the main winding coil?
When changing the auxilary face winding connection the current flow in the winding is changed so that the rotating emf direction is changed . Thats why the motor rotates in opposite direction.
How can you reverse the direction of rotation in an induction motor?
A single phase induction motor has two sets of coils and a centrifugal start switch. The start winding is in series with the start switch. The start winding provides a rotating magnetic field in one direction enabling the motor to start. The motor can be reversed by reversing the connections of either the start winding or the run winding but not both.
Why synchronous motor is not a self starting motor?
As per the operating principle of the Synchronous motor, due to continuous & rapid rotation of stator poles,the rotor is subjected to a torque which is rapidly reversing i.e. in quick succession,the rotor is subjected to torque which tends to move it first in one direction & then in the opposite direction.Owing to its large inertia,the rotor cannot instataneously respond to such quickly-reversing torque,with the result that it remains stationary or in other words it is not self starting.
If a three phase induction motor runs at a speed greater than synchronous speed?
When an induction motor is pushed over synchronous speed it will become a generator and will deliver power back to the utility.
How do you calculate the rpm of a motor with a known number of poles and a frequency of 60 Hrtz?
A synchronous motor will spin at the system frequency. 60 Hz translates into 60*60 = 3600 direction changes per minute. If this is a two pole motor (one north and one south), it will spin 1 rotation per direction change. If it is a four pole motor (two north and two south), it will spin 1/2 rotation per direction change. If this is an induction motor, it will spin at a frequency slightly less than an equivalent synchronous motor; this frequency difference is referred to as slip.
Which device is used to change the rotation of a motor in washing machine?
A device called a motor capacitor is used to change the rotation direction of a motor in a washing machine. By changing the connection of the capacitor, the motor's direction can be reversed to rotate in the opposite direction.
How do you change rotation of 6K709C dayton jet pump motor?
Interchanging the red and black leads in the motor's motor junction box will reverse the direction of rotation on the motor.
Why the DC motor is call as synchronous motor?
A 60Hz synchronous motor spins at synchronous speed - if it's a two pole motor it will spin at exactly 1800 rpms. An asynchronous motor will spin at a speed lower than the power supply frequency - a symilar asynchronous motor may spin at 1700 rpms.
How could the direction of rotation of the universal motor be reversed?
Change the polarity of either the field coils or the armature, not both and you will reverse rotation.
How do you change the direction of 3 phase motor?
Reverse any two line leads connected to the motor will reverse the directional rotation of the motor
What is difference between synchronous motor and synchronous condenser?
A synchronous motor is designed to convert electrical energy into mechanical energy to produce rotation, while a synchronous condenser is designed to only regulate voltage and improve power factor on the electrical grid without mechanical output. Both devices are synchronous machines that operate based on the principles of synchronous operation and require a magnetic field to be established.
What is the standard direction of rotation of electric motor?
standard direction of rotation of an induction motor is counterclockwise when looking from the front end i.e. non-driving end of the motor.
Why does the rotation of the motor reversed when change the polarity across the main winding coil?
When changing the auxilary face winding connection the current flow in the winding is changed so that the rotating emf direction is changed . Thats why the motor rotates in opposite direction.
How can you reverse the direction of rotation in an induction motor?
A single phase induction motor has two sets of coils and a centrifugal start switch. The start winding is in series with the start switch. The start winding provides a rotating magnetic field in one direction enabling the motor to start. The motor can be reversed by reversing the connections of either the start winding or the run winding but not both.
What is synchronous machein?
mainly alternator,synchronous motor comes under the synchronous machine.a synchronous motor is not a self starting motor.if a synchronous motor moves with more than synchronous speed then it acts as a synchronous generator.
Draw two circuit diagrams to show how a change in direction of rotation of series motor is achieved.The first diagram must represent forward rotation and the second the reverse rotation?
DC machine
