Question

A 6900/230 V,60 Hz single-phase step-down transformer is connected phase to neutral on a three phase 12,600 V distribution network. It supplies a load with impedance of 5.96+j4.44Ω. The core loss resistance and magnetizing reactance referred to the low voltage side are 400Ω and j231 Ω respectively. The equivalent winding resistance and leakage reactance referred to the low voltage side are 0.16Ω and j0.7Ω respectively.

Determine:
The terminal voltage on the low voltage side.

Answer 1

The terminal voltage on the low voltage side of the transformer is 2186.96 V.

Step-by-step explanation:

The terminal voltage on the low voltage side can be determined using the transformer equation:

Vl = Vh * (Nl / Nh)

Where Vl is the terminal voltage on the low voltage side, Vh is the voltage on the high voltage side, Nl is the number of turns on the low voltage side, and Nh is the number of turns on the high voltage side.

In this case, the voltage on the high voltage side is 12,600 V. The turns ratio can be found using the formula:

Nl / Nh = Vl / Vh

Substituting the given values, we have:

Nl / 6900 = (6900/230) / 12600

Solving for Nl gives:

Nl = (6900/230) * (12600/6900)

Nl = 40 turns

Now we can substitute the values into the transformer equation:

Vl = 12600 * (40 / 230)

Vl = 2186.96 V