30 KW MOTOR NOMALLY FULL LOAD 54 AMPS, BUT WITH OUT LOAD
30% CURRENT WILL TAKE,ANY THREE PHASE INDUCTION MOTOR WITH
OUT LOAD 30PERSENT CURRENT WILL TAKE.

No load current of a 3phase induction motor varies
according to its KW and rpm. Normally as a thumb rule
fraction HP motors (below 2.2KW) will be 50% of full load
current. Above 2.2KW may be 20% to 30% OF full load
current.

no standerd farmulla to calculate the noload current but as
a thumbrule 3 ph induction motor will draw 30% current on
no load but few motor will take 50 to 60 % current

Actually,there is no standard formula to calculate the
noload current of the motor.Normally 25% to 40% of full
load current of the motor.Also depending upon motor KW and
supplier..

There is no standerd formula for calculating no load
current, It depend on the desine and material used in
motor. There is a major role of material(winding wire&
stamoing)to anhancing the efficiancy of motor.

Equation with power factor in is the most correct. Several
issues shall be counted before estimating no load current :

- number of the poles

- power factor - there is a curve from the manufacturer
showing how this is changed in a function of power

- size of the machine

- speed

- way of feeding machine - DOL / inverter

Example :

500kW machine 690V 750rpm In=670A, No load - 285A (~42%)

500kW machine 690V 100rpm In=520A, No load - 180A (~34%)

Answer :

KW = 1.732 * V * I * cos phi * K

where K is a factor taking all other circumstances (0,7 to 1
where 1 is ideal situation) lower K for higher number of
poles, multispeed machines, specific construction etc...

what is the relation between KVAR,KVA,KW?why we are mentioning
capcitor rating in kvar?what is meant by arcing horn and horn gap
in transformer?what is equipotential wire?