Why is OC test performed on LV side and SC test on the HV side of a transformer?

Why is OC test performed on LV side and SC test on the HV side of a transformer?

As rated current is less on HV side, it is convenient to conduct this test on HV side by short-circuiting the LV terminals. This ensures that the low range of meters can be used for conducting this test as the wattmeter is connected to the primary side (High voltage side).

On which side OC test is conducted?

The open circuit (OC) test is carried out by connecting LV side (as primary) of the transformer to the AC supply through variac, ammeter, voltmeter and wattmeter instruments. The secondary side or HV side terminals are left open and in some cases a voltmeter is connected across it to measure the secondary voltage.

Why the OC test is normally done on the LV side?

Why OC test is performed on LV side? Explanation: Open circuit test can be performed on any side but for our convenience and supply voltage available we generally conduct the test on LV side, to get corresponding parameters on HV side we can use transformation ratio. Current by voltage will give net admittance. 6.

In which side should we do short circuit test and why?

Short Circuit

1. In short circuit test we have to pass rated current through the short circuited side.
2. Therefore we select High Voltage (HV) side normally for short circuiting, because it’s rated current is less and therefore it is easy to short.

Why UPF wattmeter is used in SC test?

LPF wattmeter is used to measure power in inductive circuits. Inductive circuits have the property of lagging power factor and hence these wattmeters are used. Resistive circuits have unity power factor hence UPF wattmeters are used to measure power in these circuits.

What are the advantages of OC and SC test?

These tests are very convenient as they provide the required information without actually loading the transformer. Further, the power required to carry out these tests is very small as compared with the full-load output of the transformer.

What is the purpose of OC and SC tests?

The open circuit and short circuit test are performed for determining the parameter of the transformer like their efficiency, voltage regulation, circuit constant etc. These tests are performed without the actual loading and because of this reason the very less power is required for the test.

Why iron loss and copper loss is neglected in SC and OC test respectively?

As described above, no-load current is so small that these copper losses can be neglected. Hence, now the input power is almost equal to the core losses. Thus, the wattmeter reading gives the core losses of the transformer. Sometimes, a high resistance voltmeter is connected across the HV winding.

Why short circuit test is performed on HV side?

The low-voltage (LV) winding is shorted. A balanced three-phase, alternating current (AC), variable voltage source is used to excite the high-voltage (HV) winding. Thus, all short circuit tests are performed on the HV side because the power supply capabilities (and cost) are reduced.

What is the purpose of SC test?

The purpose of a short-circuit test is to determine the series branch parameters of the equivalent circuit of a transformer.

Why is this method more accurate than OC & SC method?

Sumpner’s test or back to back test on transformer is another method for determining transformer efficiency, voltage regulation and heating under loaded conditions. Thus the Sumpner’s test give more accurate results of regulation and efficiency than O.C. and S.C. tests.

Why do you do SC / OC test on transformer?

The purpose of these tests is to determine the parameter of the equivalent circuit, voltage regulation and efficiency of the single / three-phase transformer. this is the main reason for doing SC and OC tests on the transformer. The power required during the test is equal to the power losses occurring in the three-phase transformer.

Where can I find short circuit transformer test?

1. By: Name: Pooja Dubey Course: EEE Roll No:120104026 2. Short Circuit Open Circuit Transformer Short Circuit Test Open Circuit Test Conclusion Source 3.

How does SC and OC test work on SlideShare?

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How are the circuit parameters of a transformer determined?

These circuit parameters are supplied in terms Open Circuit (OC) and Short Circuit (SC) test data of a transformer. Without actually loading the transformer, these two assessed tests give the test results which are used to determine the equivalent circuit parameters.