Page 101 - CITS - Electrician - Trade Practical
P. 101

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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