In a transformer with a 112.5 KVA rating and a primary voltage of 480-volt delta, how many amps flow through each primary winding when the secondary delivers 100 amps to a 3Ø load?

To determine the current flowing through each primary winding of the transformer when the secondary delivers 100 amps to a three-phase load, we can use the power relationship related to transformers.

The power (in VA) in a three-phase system is given by the formula:

[

P = \sqrt{3} \times V \times I

]

Where:

• ( P ) is the apparent power in VA (or KVA)

• ( V ) is the line-to-line voltage in volts

• ( I ) is the current in amps

Given that the transformer has a rating of 112.5 KVA and the primary voltage is 480 volts in delta configuration, we find that the full load current on the primary side can be calculated using the full power rating of the transformer.

For the secondary side, where it delivers 100 amps to a three-phase load:

[

P_{secondary} = \sqrt{3} \times 480 \times 100

]

This gives us the total power being transferred, but to find the primary current, we know that the primary power must equal the secondary power minus any losses (assuming ideal conditions):

Now, we must convert the KVA rating of the transformer