- #1

kelvin490

Gold Member

- 228

- 3

*a Thevenin*equivalent source is used to replace the primary circuit of transformer.

https://www.dropbox.com/s/0kaazx1d1srgirz/reflectedsource.jpg?dl=0

https://www.dropbox.com/s/0kaazx1d1srgirz/reflectedsource.jpg?dl=0

In textbook it is commonly stated that the load impedance sees an equivalent source and the open-circuit voltage is given by V

_{oc}=NV

_{1}=NV

_{s}, usually it is said that there is no voltage drop across the source impedance therefore V

_{1}=V

_{s}in this equation. However, the primary circuit itself is a closed circuit, there should be some current and voltage drop across impedance of the supply, how V

_{1}can be equals to V

_{s}?

The second question is, the short circuit current is found by NI

_{sc}=V

_{s}/Z

_{s}. It implies that when the secondary circuit is shorted, the primary current will be V

_{s}/Z

_{s}. It seems that in this case the impedance of the primary coil is ignored. Why?