There is no power loss in open circuit test.
Actually there is iron loss also known as magnetic losses. These include hysteresis and eddy-current losses. This can be described as V1^2/Rc
Where V1 is the primary voltage and Rc is the resistance of the magnetic core.
During open circuit test on transformer, no load is connected across the secondary side. Hence, the total power drawn by the transformer is only to induce the voltage across the secondary, i.e., core loss AND negligible amount of primary copper loss. As the primary copper losses during open circuit are negligible, it is practice to attribute the open circuit power to core loss.
A Linear power transformer coil? use an Ohm meter and check the resistance of the coils. No resistance is an open circuit. Also check for a cross circuit from one side of the transformer to the other.
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.
Gives us Copper loss
A volt meter will do the job.
During open circuit test on transformer, no load is connected across the secondary side. Hence, the total power drawn by the transformer is only to induce the voltage across the secondary, i.e., core loss AND negligible amount of primary copper loss. As the primary copper losses during open circuit are negligible, it is practice to attribute the open circuit power to core loss.
For open circuit test of transformer, the secondary is open circuit and the circuit impedance is largely inductive due to the core impedance having high L as compared to R. hence the power factor is reduced, thus , we use low power factor wattmeters.
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)
In case of open circuit test of transformers we measure iron losses and hence the power lost here is being measured by the wattmeter.
A no-load test is done with the normal supply connected in the way the transformer is intended to be used. It is also known as an open-circuit test to distinguish it from a short-circuit test, and its purpose is to measure the power loss in the iron core of the transformer and the no-load current drawn from the supply.
These two tests are performed on a transformer to determine (i) equivalent circuit of transformer(ii)voltage regulation of transformer(iii) efficiency of transformer. The power required for theseOpen Circuit test and Short Circuit test on transformeris equal to the power loss occurring in the transformer.
In the open circuit test, the voltage applied to the transformer is at its rated value with no load (open terminals), resulting in minimal current flowing through the windings. As a result, the copper losses (ohmic losses) in the windings are negligible since the current is minimal. The main power loss in this test is from core losses due to hysteresis and eddy currents in the core material, which are much larger than the ohmic losses when the transformer is under load.
Short circuit test and open circuit test are widely used to test the efficiency of the transformer.
open circuit & short circuit test, insulation resistance test, turns ratio, efficiency, if it is oil cooled then breakdown voltage of oil, voltage regulation and definitely visual inpection...
The short-circuit test runs the rated current through the windings of the transformer to measure the copper-loss, or power lost in the winding resistances. Because the transformer is run at low voltage for this test, there is very little additional power loss in the iron core of the transformer.
Open circuit and short circuit tests are performed to determine transformer characteristics. In the case of a single phase transformer, SC tests would be performed to determine the impedance. The open circuit test will give excitation information (% excitation at specific voltages, often 90%, 100% and 110%, and no load losses).
A Linear power transformer coil? use an Ohm meter and check the resistance of the coils. No resistance is an open circuit. Also check for a cross circuit from one side of the transformer to the other.