What is the power factor of a 3 phase induction motor operating at no load and connected to rated voltage?

At No load condition it'll be 0.2 to 0.4 lag.

Power factor will be very low around 0.2 to 0.3 lag. On no-load, motor will take magnetizing current to produce rotating magnetic field and a small amount of active current to amount for core loss. So p.f is low.

The total power required by an inductive device as a motor or similar consists of:

• Active (true or real) power (measured in kilowatts, kW)
• Reactive power - the nonworking power caused by the magnetizing current, required to operate the device (measured in kilovars, kVAR)

The power factor for a three-phase electric motor can be expressed as:    PF = P / [(3)1/2 U I]

Where:

PF = power factor

P = power applied (W, watts)

U = voltage (V)

I = current (A, amps)

Typical Motor Power Factors:

The power factor in no-load condition ranges from 0.1 to 0.3. As the motor is run on no-load the major part for the current being supplied to the motor is the magnetization current with lags the voltage by 90 degree while the stator current is very which is only required to overcome the winding and friction losses. As the load is increased the power factor improves as the as more stator current is drawn by the motor while the magnetization current remain the same.

UNDER NO LOAD THE PF IS LOW(.2 TO .4) AND UNDER NORMAL LOAD IT IS BETWEEN .6 TO .8

the power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit

Power factor= true power / apparent power.

at no load the PF will be arround 0.8 and will improve as the load increases