Formula for Synchronous Speed of Induction Machine: Induction Motor MCQ#4

The correct formula for Synchronous Speed of Induction Machine:

1. η_sync= 240*f /P
2. η_sync= 120*f /P
3. η_sync= 120/(f*P)
4. η_sync= 120*f /3P

Correct answer: 2. η_sync= 120*f /P

The sychronous speed or speed of rotation of magnetic fields can be mathematically expressed by the following relationship:

η_sync= 120*f /P

where

f = frequency

P = Number of poles