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 />
Transformer<br />
Chapter-1<br />
Equivalent Circuit of a Transformer<br />
The primary current consists of two components, load component I1' and exciting current Ie<br />
which is composed of Ic and I . Ic is in phase with V1' and the product V1' Ic gives core loss. The<br />
resistance rc in parallel with V1' represents core loss Pc = I2 Rc 2 = V1' Ic.<br />
The current I lags V1' by 90° and this is represented by a reactance X such that<br />
X = V1' / I .<br />
In transformer analysis, it is usual to refer the secondary quantities to primary side or<br />
primary quantities to secondary side.<br />
Total equivalent resistance referred to primary side<br />
re1 = r1 + (N1 / N2) 2 r2 = r1 + r2'<br />
Similarly, total equivalent leakage reactance referred to primary side<br />
xe1 = x 1 + (N1 / N2) 2 x2 = x1 + x2'<br />
In a similar way, the resistance and leakage reactances can be referred to the secondary side.<br />
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