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

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SUMMARY

This discussion focuses on determining the kVA requirement for a household to purchase an appropriate servo stabilizer, particularly for a treadmill with a 3HP AC motor. The user lives in a metropolitan area with voltage fluctuations, particularly during summer months, necessitating a stabilizer for protection. The manufacturer recommends a servo stabilizer with a minimum capacity of 3kVA. The household's sanctioned maximum load is 60A at 230V RMS, excluding air conditioners and a microwave oven, which allows for the calculation of total kVA requirements.

PREREQUISITES
  • Understanding of electrical load calculations
  • Familiarity with servo stabilizers and their function
  • Knowledge of household electrical systems and voltage ratings
  • Basic concepts of AC motors and their power requirements
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  • Research how to calculate total kVA requirements for household appliances
  • Learn about the differences between servo stabilizers and relay-based stabilizers
  • Investigate the use of Variable Frequency Drives (VFDs) for motor applications
  • Explore the impact of voltage fluctuations on appliance performance and longevity
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Homeowners, electrical engineers, and anyone involved in purchasing or installing stabilizers for household appliances, particularly those with high-power devices like treadmills and air conditioners.

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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?
 
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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.
 
Baluncore said:
What is your supply voltage and frequency?
220V RMS @ 50Hz.
Baluncore said:
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.
 
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