Electrical Machine - IES Academy
Electrical Machine - IES Academy
Electrical Machine - IES Academy
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India’s No. 1<br />
<strong>IES</strong> <strong>Academy</strong><br />
On Load<br />
Transformer<br />
Chapter-1<br />
Assuming the load to have a lagging pf, I 2 lags V 2 by θ 2 . Considering the resistive and leakage<br />
flux drop in the secondary winding, the voltage equation is E 2= V 2 + I2 z 2 where (z2 = r2 +j<br />
x2).<br />
The load component of primary current I1' is in phase opposition to the load current I 2 . The<br />
total primary current is given by the sum of I1' and I e (exciting current). Thus, voltage equation<br />
V = V ' + I 1 r + j x<br />
for the primary circuit is ( )<br />
1 1 1 1<br />
Angle θ1 between V1 and I1 is the primary pf angle under load.<br />
Transformer phasor diagram for (a) lagging p.f. load and (b) leading p.f. load.<br />
Leakage flux in a transformer depends on the currents in the windings.<br />
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