Page 589 - Basic Electrical Engineering

Open circuit test : 440 V, 1.0 A, 100 W
Short circuit test : 20 V, 22.7 A, 130 W.

Using the test data, calculate the efficiency and voltage regulation at 0.8

power factor lagging.

Solution:

Full-load current on the high-voltage side

This shows that the short-circuit test has been conducted on full load. The

wattmeter reading, therefore, represents the full-load copper loss.

W = 130 W and from oc test data,
cu
W = 100 W
c

Full-load efficiency is calculated as

Calculation of voltage regulation

Current,

From the short-circuit test data, wattmeter reading can be taken as equal to

copper losses in the windings.