A single-phase preventer continuously monitors and protects preferably which motor against phase failure?
3-phase induction motor
A Single-Phase Preventer (Single-Phasing Preventer):
- Monitors all three phases of the supply continuously.
- If one phase is lost (single-phasing), it immediately disconnects the motor.
- Protects primarily three-phase induction motors from the severe overheating and winding damage caused by single-phasing.
Single-phasing causes the remaining two phases to carry excess current → motor overheats and windings burn out if not protected.
Similar Questions
Consider the following statements about torque in synchronous motors. I. The torque in a synchronous motor is produced only when the rotor is locked into synchronism. II. The torque is directly proportional to the sine of the load angle (δ). III. Synchronous motor develops starting torque proportional to the power input. IV. Maximum torque occurs at δ = 180°. Which of the above statements are correct?
Which of the following is a key maintenance practice for reliable operation of a 3-phase induction motor?
If the frequency of an AC source is doubled, the impedance of a pure resistor ____________.
Which of the following sets of statements about the causes of errors in current transformers is correct? i) Leakage reactance in secondary winding contributes to ratio error ii) High magnetizing current increases phase angle error iii) Burden with low power factor increases phase angle error iv) Core saturation reduces both ratio and phase angle errors
Important Questions from Three Phase Induction Motor
For a slip 's' and supply frequency 'f', the frequency of current in rotor will be-
The rotating magnetic field in a three-phase, 6-poles, 50 Hz slip ring induction motor will rotate at-
The synchronous speed of a three phase induction motor having 20 poles and connected to a 50 Hz source is-
The rotor current frequency in a slip-ring induction motor depends on-
The power factor of an induction motor operating at no load is around:
