Question

A 1000 KVA three phase transformer has a secondary voltage of 208/120. What is the secondary full load amperage?

Answer 1

The three phase full load secondary amperage is 2775.7 A

Step-by-step explanation:

Following data is given,

S = Apparent Power = 1000 kVA

No. of phases = 3

Secondary Voltage: 208 V/120 V (Here 208 V is three phase voltage and 120 V is single phase voltage)

Since,

`V_(1ph) =( V_(3ph))/(√(3) )\\V_{1ph) = (208)/(√(3) )\\`

`V_(1ph) = 120 V`

The formula for apparent power in three phase system is given as:

`S = √(3) VI`

Where:

S = Apparent Power

V = Line Voltage

I = Line Current

In order to calculate the Current on Secondary Side, substituting values in above formula,

`1000 kVA = √(3) * (208) * (I)\\1000 * 1000 = √(3) * (208) * (I)\\I = (1000 * 1000)/(√(3) * (208) )\\ I = 2775.7 A`