Electrical Engineering XYZ MCQs
A motor operates in stable region at which of the following slip:
- High slip region
- Low slip region
- Both of the above
- Unity slip
Correct answer: 2. Low slip region
Explanation:
In motor operation, slip refers to the relative speed difference between the rotating magnetic field produced by the stator and the rotor speed. The slip is defined as:
Slip= (𝑁𝑠−𝑁𝑟)/𝑁𝑠 ×100%
Where:
- 𝑁𝑠 is the synchronous speed of the motor (speed of rotating magnetic field),
- 𝑁𝑟 is the rotor speed.
In the stable operating region of a motor, it typically operates at a low slip. This means that the rotor speed is very close to the synchronous speed. In this region, the motor provides efficient and stable performance. High slip regions are typically associated with starting conditions or when the motor is under heavy load, where the slip is higher and stability may be compromised. Unity slip would imply that the rotor is not moving at all relative to the rotating magnetic field, which is not characteristic of stable motor operation. Therefore, the correct choice is the “Low slip region.”