Because it is the current rating of the windings that determine the maxium load current, and the product of rated current and rated voltage, in a.c., is apparent power (in volt amperes), nottrue power (in watts).
And, incidentally, the correct symbols are kV.A and kW, not kva and kw.
kva and kw are related as KVA = (KW/PF) pf:power factor
Transformers are rated in VA or kVA. That is because the voltage is limited by the power loss in the magnetic core, and the current is limited by the power loss in the resistance of the windings. The rated voltage times the rated current gives the transformer's rating in kVA.
To convert AC tonnage to kVA and kW, use the following formulas: For kVA: kVA = (tonnage x 3.517) For kW: kW = (tonnage x 3.517 x power factor). Remember to consider the power factor of the system when converting from tonnage to kVA and kW.
You can't determine the output voltage of a transformer by knowing kva. Transformers will be marked as to input and output voltages. Some will have multiple input and output voltages. The output voltage depends on the ratio of coil turns between input and output.
Transformers, like inductors can only handle a specific amount of voltage and current before overheating, with AC or DC input. AC 'real' power delivery from a transformer is measured in kilowatts (kW) which is identical to KVA when "Power factor = 1". In the extreme, with "Power factor =0", a transformer could be fully loaded in terms of KVA, while supply zero 'real' power (kW).
The same way, as you convert Appels to Carrots ........... There is a formula: KVAr = KVA / KW or cos=KW/KVA > Yes, we are treating KW, KVA, & KVAr as the 3 sides in a 90 deg TRIANGLE ! KW= vertical katede KVAr = horizontal katede KVA = hypotenuse
KW is multiplication of KVA and power factor. Power factor is load dependent and varies as per the type of load. Hence the rating or capacity is mentioned in KVA not in KW
Transformers are rated in KVA which is equivelant to "apparent power". Loads, {such as heaters, lamps, etc.} are rated in KW which is equivelant to "real power". Things such as power factor and transformer efficiency account for the diifference between the two values. KW's are what the load requires and KVA's are the values of the input power required in order to serve a given KW load. Unfortunately the utilities charge for KVA not KW. It's not too unlike a glass of beer. The enjoyable part is the beer itself. However, you pay for both the beer and the foam at the top of the glass.
To convert kilowatts (kW) to kilovolt-amperes (kVA), you can use the formula kVA = kW / power factor. If we assume a typical power factor of 0.8, 360 kW would be approximately 450 kVA (360 kW / 0.8 = 450 kVA). If the power factor is different, you would need to adjust the calculation accordingly.
To convert 2 kW to kVA in single phase, you need to know the power factor. If we assume a power factor of 0.8 (common for many single-phase loads), the conversion formula is kVA = kW / power factor. Therefore, for 2 kW at a power factor of 0.8, the result would be 2 kVA / 0.8 = 2.5 kVA.
kVA = kW divided by (power factor). The power factor is the cosine of the angle between voltage and current.
Multiply by Amps.