Why machinery used on a.c supply is usually rate contained by KVA instead of KW?
Answers:
It is because machinery used on ac supply are transformer regulated and the certainty that transformers are rated in KVA so as machineries used on ac supply should be given contained by KVA rating.
AC supply machines are rate in KVA . The total power consumed or supplied by the system depend up on the power factor of the load. As you know KVA= KW / Power factor.KW will cash for power factor.
Also size of a AC system is depend up on the insulation requirement (depend upon voltage) and size of conducting material( depend upon the current) so Voltage x current will give VA or Size of AC system
All AC power sources like transformers, generators, inverters etc. are usually rate in KVA.
The reason is that surrounded by the case of a power source, you cannot predict the type of load (resistive, Capacitive or Inductive) that will be connected to it. Hence the actual usable size rating depends on the power factor of the load.
Power = Voltage x Current x Power Factor
If the load is resistive, PF is 1 (unity) and if the nouns is inductive, it will be less than unity.
Thumb Rule - adjectives AC power sources - Generators, Transformers, UPS etc. are rated in KVA and adjectives loads are rated in Watt, Kilowatt or Horse Power (HP)
no resolved reason but kva is more accurate than kw since the first uses the fundemental units of electricity and expresses them
I suppose because the unit of power is a Volt.
You mean apart from the fact that that's the means of access everybody else does it, so you'd better go along with it?
Volts tell you how tough the insulation has to be. That's important. Amps tell you how big the conductors have to be. That's important too. Watts would relate you how much heat it will generate. This is important, but the lowest important of the three, and variable beside the power factor anyway, whereas the other two apply all the time.
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