Page 101 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

EXERCISE 42 : To conduct OC and SC test of transformer

Objectives

At the end of this exercise you shall be able to
• identify the HV & LV terminals of transformer, and check KVA of transformer.
• make the connections of transformer with wattmeter, voltmeter & ammeter.
• conduct open circuit test & short circuit test of transformer.
• measure the iron losses & copper losses of transformer.

Requirements

Tools/Equipments/Instruments
• Combination plier (165mm, insulated) - 1 No. • Multi meter (Digital, 3 digit) - 1 No.
1/2
• Screw Driver (150mm, insulated) - 1 No. • 1 Ph. Auto transformer (0 - 260 V, 10 A) - 1 No.
• Neon Tester (75mm, 500 V) - 1 No. Materials/Components
• Electrician knife (Insulated) - 1 No. • Test lamp (60 W, 230 V) - 2 meter.
• Voltmeter (MI, 0 - 600 V) - 1 No. • DPST switch (250 V, 32 A) - 1 No.
• Voltmeter (MI, 0 - 300 V) - 1 No. • Connecting wire (2.5 sq.mm) - 1 role.
• Ammeter (MI, 0 - 10 A) - 2 Nos. • Cotton waste / cloth - as reqd.
• 1 Ph. Watt meter (MI, 2KW) - 1 No.
• 1 Ph. Transformer
(1 KVA, 415 V/230 V) - 1 No.

Procedure

TASK 1 : Identify the HV & LV terminals of transformer

1 Collect the Tools, equipments & materials required for experiment.
2 Draw the circuit diagram of OC test and SC test of transformer.
3 Check and identify the HV & LV side and KVA rating of transformer.
4 Check the voltage rating of HV & LV side of transformer.

TASK 2 : Conduct OC test of transformer
1 Make the connection of OC test of transformer as per circuit diagram.

2 Connect LV side of transformer to the supply.
3 Ensure that all meters are connected on LV side and HV side terminals are is kept open.
4 Check the connections and switch ON the supply.
5 Record the readings of voltmeter, ammeter and watt meter.
6 Switch OFF the supply and disconnect the transformer and meters.

TASK 3 : Conduct SC test of transformer
1 Make the connection of SC test of transformer as per circuit diagram.
2 Connect HV side of transformer to the supply through the auto transformer.
3 Ensure that all meters are connected on HV side and LV side terminals are shorted with thick copper conductor
OR connected with ammeter.

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