Question

How is the slip of a three-phase asynchronous motor defined and what is its value when starting the motor?

Answer 1

Answer:

Slip value is calculated as:

s=(Omega - OmegaS)/OmegaS

s - slip value

Omega - actual speed of shaft rad/s or RPM/m

OmegaS - synchronous speed of shaft

So if Omega of 2 pole motor actual speed is zero (starting motor) the slip value is:

(0–3000)/3000=1

If motor spins fully at synchronous speed (2 pole) than

(3000–3000)/3000=0

In case of 4 pole motor it is same except 3000 becomes 1500. But slip values remain.