This document describes open circuit and short circuit tests performed on transformers. The open circuit test is done to measure iron losses by connecting meters to the primary side with the secondary open. The short circuit test is done to measure copper losses by shorting the secondary and applying a small voltage to the primary side. These tests allow determining key transformer parameters like losses and efficiency without actual loading and are economical and convenient.

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
1. To connect Wattmeter in primary side.
2. To connect Ammeter in series of phase.
3. To connect Voltmeter in parallel of primary
side.
4. We will open the Secondary side.
5. 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
1. To connect the wattmeter primary side
2. To connect the Ammeter in series of primary
side
3. To connect the Voltmeter in parallel of
primary side
4. Short the secondary side using thick
conductor
5. 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