How Do I Calculate the Required Kvar for a 22KW Motor?

[ssana]

Dear all,

I have one 22KW motor.
I want to know how much Kvar i need to install for it.
According to my information, i need to check no load current of motor (it is taking 10 ampere at no load), and than take 90% of no load current (90% of 10 ampere is 9 ampere), so install capacitor that can take maximum 9 ampere current (6 kvar capacitor takes 9 ampere current).
So 6 Kvar is suitable to install in 22KW motor.
Am i calculating in correct way?

 

[NascentOxygen]

I can't help with your question, but I was looking at your figure of 9A for 6kVAR. This implies a supply voltage of 667v. Perhaps I am not doing this right.

This is a 3 phase motor, is it? Maybe that 6kVAR is a set of capacitors drawing 2kVAR per phase? Seems an odd way to rate it, if it is, summing the phases. But the figure of 2kVAR at 9A would give a phase voltage of 220v which might be more likely.

So what is your phase voltage there?

Do you have a table of kVAR vs. current for power factor correction capacitors? If so, do the kVAR figures all turn out to be exact multiples of 3?

 

[ssana]

Dear NascentOxygen,
Using three phase formula,
Power = Voltage x Current x √3
Power = 380V x 9A x 1.732
Power = 5923 VA
OR
Power = 5.923 KVA
Approximately 6 KVA

Hope that this will helpful to you.