Design and specify the ratings of a single-phase transformer to supply several loads from 600-V

source. The design must include the determination of the transformer's kVA rating, and

specifications of its primary and secondary currents. It should also attempts to determine the

efficiency of the transformer under different loading conditions (LD's).

Starting a transformer generally requires more current than running it at its normal LD. To account

for this additional current requirement, it's often helpful to put a start factor of 20% extra into the

design calculations.

a. Consider additional future loads of 10% of current total load capacity).

b. Calculate the total kVA required for the transformer (including the additional

future loads and the starting factor).

c. Use the typical "Standard Transformer Sizes"; see table below.

d. Determine the primary and secondary currents of the transformer.

e. Determine the full load capacity in kW.

f. Calculate the full load efficiency using the following assumption:

1. The core losses are equal to 600-W + XX-W; XX is your last two digits serial

number as posted in BB under EE306 common sections (e.g., 01, 04, 10, 14, 21

...etc.)

2. The full load copper losses are equal to 900-W+Y-W; Y is your one digit section

number as posted in BB under EE306 common sections (e.g., 1, 2, 6...etc.)

g. Calculate the efficiency of at least 3 different loading scenarios of your own choice

(e.g., LDs1: Air Conditions & Lighting; LDs2: Laundry & Kitchen equipment; etc.)

h. Calculate the maximum efficiency of the transformer when operating at a power

factor of 0.9