What happens when synchronous motor is loaded beyond pull out torque?
If it is loaded beyond the value of pull out torque, it will continue to operate as a single phase induction motor up to 500% of its rated output. As a result of the magnetic rotating field created by a starting and running winding displaced 90 degree in both space and time.
What happens when a synchronous motor is overloaded?
When a synchronous motor is overloaded, the rotor is forced out of synchronism with respect to the rotating stator field and the motor slows down. … It is even possible to “over-excite” the motor in this fashion, making it create reactive power (leading power factor).
What is pull in torque in synchronous motor?
Pull-in Torque – the amount of torque in which the motor may move the load without acceleration.
What is pull out torque?
: the maximum torque a motor will carry without an abrupt drop in speed.
What happens when motor load increases?
Assuming it is not being controlled at a constant speed, then really the same thing happens in all three cases. As the load is increased, the motor will slow down, and the torque will increase. Current into the motor will also increase. If the load is increased above the maximum, the motor may overheat after a while.
Does the excitation affect the synchronous motor speed?
From the above discussion, it is concluded that if the synchronous motor is under-excited, it has a lagging power factor. As the excitation is increased, the power factor improves till it becomes unity at normal excitation. Under such conditions, the current drawn from the supply is minimum.
When a synchronous motor is loaded its speed?
When a synchronous motor is loaded, though the speed remains constant but the load angle α increases i.e., the angle by which the rotor pole axis lies behind the stator pole axis increases.
Will increase in load the speed of synchronous motor?
Thus, if the load on a synchronous motor is increased the following points are considered which are given below. The motor continues to run at synchronous speed. The torque angle δ increases. The excitation voltage Ef remains constant.
What are the advantages of synchronous motor?
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.
What is are the factors affecting the torque angle for synchronous motors?
Thus, a synchronous motor has no self starting torque. To make the motor starting the unexcited rotor is speeded up to synchronous speed by some arrangement and then excited by DC source. … The value of the torque angle depends on the amount of load to be met by the motor.