Page 118 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

5 Check & verify the CT ratio with different primary input current within the CT range.
6 Switch OFF the current injection kit and disconnect the CT connection.

7 Calculate the primary current with CT ratio.

TASK 3 : Connect and test the PT
1 Make the connection of primary terminals P1 & P2 of PT across the voltage injection kit.
2 Make sure that voltage injection kit is OFF and its knob is at zero position.
3 Connect the secondary terminals S1 & S2 of PT to the voltmeter of low range.
4 Switch ON the voltage injection kit and gradually increase the PT primary voltage until PT secondary voltage
reaches 110 V
4 Note down the primary voltage and secondary voltage.
5 Check & verify the PT ratio with different primary input voltage within the PT range.
6 Switch OFF the voltage injection kit and disconnect the PT connection.

7 Calculate the primary voltage with PT ratio.
Tabular column:

Ratio Primary input Secondary output
CT 30/1 A 10 A
20 A

30 A
PT 440/110 V 220 V

300 V
440 V

Safety precautions:
1 Do not make wrong and loose connections.
2 Do not inject the voltage and current to CT & PT more than rated value.
3 CT secondary should always be kept shorted.

4 Do not test High Tension CT’s & PT’s

101

CITS : Power - Electrician & Wireman - Exercise 49