In a short-circuit test the normal load current is passed through the transformer with minimal voltage applied.
This means that the magnetic flux density in the core is also minimal, so that the only losses are the resistive losses of the transformer windings.
This is what is known as a "short circuit".
The transformer can be tested on open and short circuit to find the iron losses and copper losses separately, which uses a fraction of the power than having to run the transformer on full-load.
I am so sorry for your core losses
Open circuit means the circuit is not continuous . A short circuit is continuous but has a fault connecting between either live to neutral or earth .As result of this we saw that this answer is unsufficent to explain short and open circuit on the other hand you can use this answer also like i did:)
in the short circuit test we applied supply voltage on L.V side and short circuit the H.V side and connect the ammeter in H.V circuit to measure the short circuit current. with the help of s.c test we measure the copper losses in the transformers.
The unit for short circuit current is typically measured in amperes (A) or kiloamperes (kA). It represents the maximum current that can flow in a circuit under a short circuit condition.
Because a short-circuit test is done at very low voltage to check the transformer windings on their maximum current. The low voltage ensures that the magnetic flux in the transformer's iron core is very low so that the eddy-current losses, usually known as iron losses, are negligible.
Because a short-circuit test is done at low voltage so there is very small power loss in the magnetic core. That is because there is very magnetic flux.
The resistance of the winding in the primary of a transformer constitutes a load. As long as there is resistance then there is no short circuit. A short circuit is considered no resistance which develops an instantaneous high current. That is why fuses and breakers are inserted into the circuit to open the high current flow under a short circuit condition.
The short-circuit test on a transformer primarily assesses the copper losses, represented by i²R losses, because it is performed at a reduced voltage that allows full-load current to flow while keeping the output voltage low. In this condition, the magnetic circuit is already magnetized from prior tests, so the core does not require significant additional magnetizing current, thus minimizing excitation losses. Consequently, the test focuses on the resistive losses in the windings rather than losses due to hysteresis or eddy currents in the core.
An open-circuit test is done with the transformer running at its rated voltage but with no load. This measures the power lost in the magnetic core. (IR Losses) A short-circuit test is done with the transformer running at its full rated current in all windings but at a low voltage. The secondary is shorted and the primary voltage is adjusted to give the rated current. This measures the power lost in the copper windings. (Copper losses)
1)Short circuit test is performed at rated current. As the rated current on high voltage side is much less than low voltage side, so the rated high voltage side current is easily achieved compared to low voltage side. 2)Also because we cannot short circuit high voltage side, as, if we short circuit high voltage side, voltage of high voltage side essentially falls to zero and since VI=constant, so the high voltage side current will be very high and will burn the winding.