How to determine kVA for my house? (to buy a servo stabilizer)

[Wrichik Basu]

I just got a treadmill delivered. It is semi-commercial with a 3HP AC motor that can go to 6HP at peak. The Amazon product page said that a stabilizer is recommended. We live in a metropolitan city, so voltage variations aren't too much, but we do have sudden fluctuations once in a while, and steady low voltage in the summer when everyone is using air conditioners. So all costly appliances like air conditioners and refrigerators have relay-based stabilizers. But for a 3HP motor, only servo stabilizers will work. I had a word with the manufacturer; they said it's better if I buy a stabilizer to protect the motor and MCB, and of course, he also confirmed that it has to be a servo stabilizer. I should be buying one that can support a minimum of 3kVA.

The thing is, servo stabilizers are costly. I was wondering if it is logical to pay a bit more and get a servo stabilizer for the entire house. ("Entire house" excludes air conditioners and microwave oven, but includes the refrigerator.) We have a sanctioned maximum load of 60A (at 230V RMS mains). Deduct two air conditioners and one microwave oven; each takes about 11A at peak. With this data, how do I calculate the kVA for my house?

 

[Baluncore]

What is your supply voltage and frequency?
How much variation of voltage do you see ?

A servo based stabiliser transitions smoothly, without interruption to the supply. A relay based stabiliser, will have short periods of interruption while switching, when there is no power output. That may reset a controller or computer system.

The third way is to use a VFD, variable frequency drive. That should produce a steady output at the mains frequency and voltage expected.

 

[Wrichik Basu]

What is your supply voltage and frequency?

220V RMS @ 50Hz.

How much variation of voltage do you see ?

Sudden fluctuations can go down to 190V; in summer, during high usage of air conditioners, we have seen it go to 180V.