Basic Formula to Calculate Apparent Power in Single and Three Phase Circuits

The essential equation to figure evident power in any circuit is:

S = VI

where S = Evident power estimated in VA (volt-amperes)

V = Voltage

I = Current


Mechanical unit 

Unit VA is little for overwhelming gear and for all intents and purposes kVA is utilized rather than VA.

Where S (kVA) = VI/1000

In single and three stage circuit the kVA recipes are:

Single phase kVA = [V * I] / 1000

Three phase kVA = [E * I * 1.73] / 1000

Case 1: Locate the obvious power in kVA drawn by a 200 V single stage generator having 2 Amps current going through it. 

Arrangement: kVA = 200 * 2/1000 = 0.4 kVA 

Illustration 2: Locate the current drawn by 500 kVA transformer @ appraised voltage 5 kV. 

Arrangement: By cross augmentation: 

I = (500 * 1000)/(1.732 * 5k) = 57.73 Amps