What is the effect of the synchronous motors to the power factor?
A Synchronous Motor can be made to operate at unity and leading power factor by just increasing its excitation voltage i.e. by increasing the field current. This advantage of Synchronous Motor is used to improve the power factor.
What is the effect of the induction motors to the power factor?
The power factor can be controlled by manipulating either of active or reactive power. In induction motors, active power is proportional to the motor load that variation of motor load results in increase or decrease in power factor.
How the power factor of the input power to a synchronous motor may be adjusted?
The fact that the field poles of a synchronous motor are magnetically in line with the stator flux allows dc current on the field to replace ac magnetizing current on the stator. Since power factor is determined by the magnetizing current, the power factor is adjustable by changing the field current.
What is the difference between synchronous and induction motor?
Induction motor runs at the non-synchronous speed. The synchronous motor works on the principle of the ‘Magnetic Locking’. The induction motor works on the principle of ‘Electromagnetic Induction’. It is a non-self starting motor.
Why are synchronous motors more efficient?
Synchronous motors generally have a higher power density than induction motors of comparable size, allowing them to provide more power at a smaller volume. … Synchronous motors can achieve efficiencies of >90% in some cases and are generally more energy-efficient than induction motors.
What happens when an induction motor runs at synchronous speed the motor will?
So, theoretically, the Induction motor can never run at synchronous speed. … But due to the reduction of speed, again lag influx will be achieved, and the motor will continue to move at this speed due to flux difference between rotor and stator. In short, an induction motor cannot run at induction speed.
What happens when induction motor runs above synchronous speed?
The stator winding of an ac machine produces a rotating mmf which rotates at synchronous speed: … The rotor must rotate at speeds other than synchronous speed for torque to be produced. If an external mechanical system drives the rotor above synchronous speed, the induction machine acts as a generator.
What is power factor in synchronous motor?
Synchronous motors are designed to operate at unity (1.0) power factor or 0.8 leading power factor. By varying the DC excitation of the motor, the power factor of the motor can be varied widely. Overexcited synchronous motors operate at leading power factor and provide reactive kVAR-like capacitors.