Answer / j.kesavan

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.

Answer / d.g.skandan

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.

Answer / mahmoud

In=p/1.732*v*p.f

=30x1000/1.732*.8*380

=57A

Ino=57/3
19A

Answer / suresh

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

Answer / suthan prabhu

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..

Answer / vikram

P = 30 kw
V= 415
I = ?
PF =0.8
p= 1.732 VI PF

I = 30000/1.732*415*0.8

I= 52.17 Amp (Full load current)

No load current will be 30% of FL current

N.L Current = 30% * 52.17

NLC = 15.65 A (Without taking Efficiency of motor into account)

Answer / surajkant

practically the no load current of 3 phase motor varies
from 25% to 35% whereas in 1phase it is nera to full laod.

Answer / s.p.singh

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.

Answer / pillay

I agree with suthan prabu. there is no formula to calculate.
depends on the manufacturers design, but full load curret can be calculated.

Answer / k.arivazhagan

3 ph induction motor will run 30% current on
no load but few motor will take 40% current


EXAMPLE:

KW=3.7KW,Amps=7.45,(Assume 40% Of No Load Amps)

No Load Amps = 7.45*0.4
= 2.98A

I am having a DG set.The 415 V from Generator is step up to 460 v and then the same is used for Induction furnace. before Step up, I am connecting LT load to my factory use. When Induction furnace is in service from DG, when i try to start a motor, the generator is tripped.Please tell me the reason.

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