Question

Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:

Statement (I): Large power transformer testing under full load current is not possible.

Statement (II): Short circuit test of transformer gives indication of copper loss.

1. Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I)
2. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)
3. Statement (I) is true but Statement (II) is false
4. Statement (I) is false but Statement (II) is true

Answer 1

Correct Answer - Option 2 : Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I)

Statement (I):

A large power transformer in loaded condition carries large amount of current and voltages. So, it’s very difficult to arrange such high rating voltmeter, ammeter and wattmeter. Therefore, the testing under full load current is not possible.

Statement (II):

Short circuit test:

It is done by shorting one of the winding terminals (usually low voltage terminal) and applying a small voltage across the other winding terminals (high voltage terminal because the current in HV terminal will be less and easy to handle) and using a wattmeter to measure the power dissipated in the LV terminal. Wattmeter will indicate the full load copper loss.

Short circuit test is done to find

• The full load copper loss
• Short circuit current

 

Therefore, both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I).