Calculation of AC Motor Power

Baig... if you are only concerned about the motor loss, and not the driven-machine loss, then 20% is way too high.

If you are interested in a more realistic value, then please provide the motor's nameplate Hp or kW, its rated voltage, and its rated speed or number of poles!

Regards, Phil Corso
 
Hi,

Many motor nameplate does not indicate motor Eff, or PF.
So based on motor voltage and current listed on name plate, how can match the power calculated with the power listed on nameplate?

Regards
Wael
 
B
You cannot calculate the PF of a motor from its nameplate. The PF varies with the actual load on the motor. The more energy the motor is actually delivering to the load, the higher the PF will be. A lightly loaded motor will have a low PF.
 
Wael… if the motor's nameplate gives its rated temperature-rise there is way to obtain the information you seek!

Determine its temperature-rise over ambient, then, Hp(out), kW(in), kVA(in), PF, and Efficiency, can be derived, with reasonable accuracy!

Please note, this was the procedure used way before the introduction of Clamp-On Watt meters!

I suggest you search the Control.Com Archives for similar topics. If your search proves inadequate for your needs, then contact me.

Regards, Phil
 
Hi,

what if i just have v and i values,

then how we will find the motor power and what will be power factor for motor in India.
 
J
I secured an Induction motor properties chart from Teco and compared it with other motor properties chart. The I've got provides a graph for the torque and current plotted against a load/torque current for vertical values and % synchronous speed for horizontal axes.

Dividing the heights of the full load current and full load torque into 100 segments and manipulating these in auto CAD, I was able to get values for the RPM, Torque, and with some math, the efficiency and the power factor.
 
E

eng. mohamed

I want to ask about the percentage of the power between the motor of submersible pump and shaft power of pump if this pump is dry type. I mean what about of the heat coefficient between motor and pump with cooling jacket?
 
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