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Question
How to calculate unit consumption on the basis of load. 
kWH=kwXhrs.is it correct? kw is motor load.What is unit 
consumption at 100% load, 50% load & on no load.
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
For three phase motor we needs to consider the PF also.
P = Sq.Rt 3 X V x I x pf
 
Is This Answer Correct ?    41 Yes 5 No
Satish M
 
Answer
# 2
Unit consumption is KW x Hrs.

But while you need to calculate the KWH consumed by a motor,
multiplying KW of motor (nameplate KW) and hour will not
give you the energy consumed. This is because the name plate
KW in a motor is not the electrical power, but the
mechanical power output provided by the motor (Electrical
Power = Frictional losses + Eddy current losses + Copper
losses + air gap losses + Mechanical power). In order to
calculate the energy consumed by the motor you can use the
formula

single phase AC = Voltage x Rated current x Power factor x
Hrs run. (100% load)

3 Phase AC = 1.732 x Voltage x Rated Current x Power factor
x Hrs run. (100% load)

Normally the power factor of motor is considered between 0.8
to 0.85 at full load operation.

At no-load, motor will take approx 40% of its rated full
load current (again this depends on the design of motor, but
normally assumed to be near 40%). So at 50% load, the motor
will take a current around 70 to 75% of its full load rated
current. so we can approximate as

energy consumed at 50% load (motor - 3 phaase) = 1.732 x
Voltage x 75% rated full load current x power factor x Hrs run .

at no load = 1.732 x Voltage x 40% of rated current x power
factor x Hrs run.
 
Is This Answer Correct ?    19 Yes 2 No
Shannu
 
 
 
Answer
# 3
kwh=kw*hrs is not correct.
kw=1.732*v.i.0.85,if motor rated current 64amp,
Then calculated value kw=1.732*415*64*0.85
 
Is This Answer Correct ?    6 Yes 3 No
Shivpal Prajapati
 
Answer
# 4
i have 70 hp 3 phase load. I run 70 hp in 1 hour in perday
what is kwh
 
Is This Answer Correct ?    5 Yes 3 No
Sakil Belim
 
Answer
# 5
In single phase
KW= Voltage X current
In 3 phase
KW= Sq.Rt 3 X V x I
For 100% load I=I
For 50 % load I= 50/100 X I= I/2

I is the rated current of the machine


 
Is This Answer Correct ?    29 Yes 34 No
Prabhu
 

 
 
 
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