Page 48 - Electrical Equipment Handbook _ Troubleshooting and Maintenance

TRANSFORMERS

TRANSFORMERS 3.5

I
V aV I S
P S P
a
the apparent impedance of the primary is

V aV V
Z' P S a S
2
L
I P I S /a I S
2
Z' a Z
L L
It is possible to match the magnitude of load impedance to a source impedance by simply
selecting the proper turns ratio of a transformer.

ANALYSIS OF CIRCUITS CONTAINING IDEAL
TRANSFORMERS

The easiest way to analyze a circuit containing an ideal transformer is by replacing the por-
tion of the circuit on one side of the transformer by an equivalent circuit with the same ter-
minal characteristics. After substitution of the equivalent circuit, the new circuit (without a

FIGURE 3.3 (a) Definition of impedance. (b) Impedance scaling through a trans-
former.

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