Because the machines which use power i.e; load, are always rated in KW and the machines which produce power i.e generators, are rated in KVA.
AnswerA motor's mechanical load is expressed in watts (horsepower in North America), so the output power of the motor must also be expressed in watts (horsepower in North America) so that the machine can be matched to its load. You cannot express a mechanical load in terms of volt amperes.
To determine the transformer rating in KVA for a 55 kW motor, you can use the formula: KVA = KW / Power Factor. Assuming a typical power factor of 0.8 for motors, the calculation would be KVA = 55 kW / 0.8 = 68.75 KVA. It's advisable to round up, so a transformer rated at 75 KVA would be appropriate to ensure adequate capacity.
kva*cos(phase angle)
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)
The kW rating of a transformer can be calculated by multiplying the kVA rating by the power factor. For example, if the power factor is 0.8, then the kW rating of a 100 kVA transformer would be 80 kW. You can also use the formula: kW = kVA x power factor.
To determine the KVA needed to run a 55 kW motor, you can use the formula: KVA = KW / Power Factor. Assuming a typical power factor of 0.8 for motors, the calculation would be KVA = 55 kW / 0.8 = 68.75 KVA. Therefore, approximately 68.75 KVA is needed to run the 55 kW motor. Adjust the power factor accordingly if you have a specific value for your motor.
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.
Rating for DG set and any of electrical machines is calculated in KVA. KVA is calculated as KW/pf. One can calculate the required KVA for DG set with this formulation: (KW/pf)/load rate. For example KW=110, pf=0.8 and one loads the DG at 75%, so KVA= (110/0.8)/0.75=185 KVA.
kva and kw are related as KVA = (KW/PF) pf:power factor
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.
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.
depending on kva class of the motor between 4-8 times the running current
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