open circuit and short circuit test on transformer

how to measure on load and no load losses

1. OPEN CIRCUIT & SHORT CIRCUIT TEST ON TRANSFORMER PREPAIRED BY: MANAVAR MILAN

2. INTRODUCTION Necessity of testing Open circuit test Short circuit test Advantages Application

3. NECESSITY OF TESTING In transformer and other equipment have input and output. Hence how to we find the performance of transformer and other equipment…..? We have a solution even we will find the loss of transformer so we can easily find the all parameters of transformer like, we can find iron loss, cu loss, impedance, no load current, short circuit current and efficiency.

4. OPEN CIRCUIT TEST

5. HOW TO MEASURE O.C. TEST To connect Wattmeter in primary side. To connect Ammeter in series of phase. To connect Voltmeter in parallel of primary side. We will open the Secondary side. We will give the supply primary side for the measurement of iron losses.

6. The purpose of this test is to find the no-load loss or core loss. A wattmeter, voltmeter and an ammeter are connected in low voltage side. Secondary side of transformer we will keep open. We give the normal voltage applied to the primary, normal flux will be set up in the core, hence normal iron losses will occur which are recorded by the wattmeter.

7. As the primary no-load current is measured by ammeter and its value is small, Cu-loss is negligibly small in primary and nil in secondary (it being open). Hence, the wattmeter reading represents practically the CORE LOSS under no-load condition.

8. Sometimes a high resistance voltmeter is connected across the secondary. The reading of the voltmeter gives the induced e.m.f. in the secondary winding.

9. SHORT CIRCUIT TEST

10. HOW TO MEASURE S.C. TEST To connect the wattmeter primary side To connect the Ammeter in series of primary side To connect the Voltmeter in parallel of primary side Short the secondary side using thick conductor Now give the small voltage supply for the measurement of Cu-losses.

11. A wattmeter, voltmeter and an ammeter are connected in high voltage side. The low voltage side of transformer is short circuited. The applied voltage is a small percentage of the normal voltage. Hence the core losses are very small with the result of the wattmeter reading represent the full-load CU-LOSS or loss for the whole transformer .

12. ADVANTAGES No require for extra load This test are very economical and convenient, because they furnish the required information without actually loading the transformer.

13. APPLICATION By using open circuit test we can measure the loss of no-load losses means that iron losses. By using short circuit test we can measure the loss of full-load losses means that Cu-losses. We can find the efficiency by using of iron losses and cu-losses.

14. THANK YOU