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Why is the capacity of a transformer specified as KVA and not as KW?
Wiki User
∙ 10y ago
Because its the product of the rated secondary voltage and rated secondary current, which results in volt amperes. To determine the number of watts, it's necessary to know the power factor of the load, which the designer has no control over.
Wiki User
∙ 10y ago
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Why transformer are rated in kVA instead of KW?
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.
Why transformer rated in kva instead of kw?
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
1 12hp motor takes what kva?
12HP is approximately 10.8 KVA. You would want to use a 15KVA transformer to supply this motor. KW = HP * .75 KVA = KW * 1.2 (These formulas are approximate)
Which is to consider in sizing generator kva or kw ratins?
the unit of generators power is KVA becoze the kva is the power that contain the active power (KW) and the reactive power mean that the name plate of any generator must contain the rated kva of it (like the transformer P (KW) = P (kva) * cos fi P (KW) = V I cos fi for single phase P (KVA) = V I when cos fi closed to 1 this will increase the useful power that exit from the generator or transformer with my pleasure
How do you calculate the output voltage of a transformer if kva rating is known?
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.
Why generating station capacity mentioned in KW even though alternator rating is in KVA?
In generator station the power which produced is real power the real power to me mentioned in its's factor so it is mentioned as KW or MW. In transformer there is no effect of change the power factor (ie:cos,phi) and the power which transfer do not changes its frequency. so, in Transformer and generator it is mentioned as KVA.
What is the difference between KVA and KW of a transformer?
Transformer power is given by P=V*I which takes the unit of KVA while that of KW has energy term which is not produced by the transformer.It only steps up or down the voltage.Answer:In a pure D.C. circuit, KW = KVA. However, in any A.C. circuit, there is real power {KW} and apparent power {KVA}, due to the voltage and current being out of phase. Power Factor is the ratio of KW to KVA. Transformers are rated in both KVA and PF. Multiplying the transformer KVA rating times the PF will yield KW.A transformer has separate ratings for maximum voltage and maximum current. Multiply the two together and that is called the VA rating, or kVA for larger transformers. So the transformer rating is independent of the power factor of the load.
How many kva is 21000 kw?
KVA is the vector sum of real and reactive power; put differently, KVA at a specified power factor will tell you how many KW you have: KW = KVA * pf You must provide a power factor or power factor angle (if angle, replace pf with cos (pf) in above equation) or total reactive power to calculate.
Why transformer is read in rating KVA but not 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.
Why transformer rating is called kva not kw?
Transformers are rated in KVA because that is a more accurate way to measure their capacity requirements. KWH is apparent power, while KVA is true power, and the ratio between them is power factor. The power factor is a function of the load, and not the transformer, so a poor power factor would make KWA look less to the transformer while, in fact, the true power, if not met by the transformer, could overload the transformer.
37 kilowatta equals how many kVA?
kva and kw are related as KVA = (KW/PF) pf:power factor
What is the capacity 0f 100 KVA electric transformer?
KVA means thousands (K) of volts (V) times Amperes (A). A 100 KVA transformer can deliver 1000 amps at 100 volts or 500 amps at 200 volts etc.
