Page 103 - CITS - Electrician - Trade Practical
P. 103

ELECTRICIAN - CITS


           EXERCISE 43 : Loading and determine the efficiency of

                                     single phase transformer


           Objectives

           At the end of this exercise you shall be able to
           •  check the primary & secondary voltage and KVA of transformer
           •   connect and apply resistive & inductive load on transformer
           •   calculate the losses occurred in transformer and find the efficiency of transformer
           •   calculate the efficiency of transformer at different loads and power factor.

           Requirements

           Tools/Equipments/Instruments                        Materials/Components
           •   Combination plier (165mm, insulated)  - 1 No.   •   PVC copper wire (1.5 sq.mm)    - 2 meter.
           •   Screw Driver (150mm, insulated stem) - 1 No.    •   Test lamp (100 W, 230V)        - 1 No.
           •   Neon Tester (75mm, 500 V)        - 1 No.        •   Insulation tape (PVC, 19mm)    - 1 role.
           •   Electrician knife (Insulated)    - 1 No.        •   Cotton waste                   - as reqd.
           •   Voltmeter (MI, 300 V)            - 2 Nos.
           •   Ammeter (MI, 10 A)               - 2 Nos.
           •   Watt meter (MI, 10A, 400 V)      - 2 Nos.
           •   1 Ph. Transformer (400V/230V)    - 1 No.
           •   Lamp load (250 V, 5 KW)          - 1 No.
           •   Inductive load (AC motor) (230V, 2 HP) - 1 No.

           Procedure

           TASK 1 : Identify the rating of transformer
           1  Collect the Tools, equipments and materials required for experiment.
           2  Draw the connection diagram of loading & efficiency of 1 ph. transformer.

           3  Check the primary & secondary voltages and KVA of transformer.
           4  Identify HV & LV side and check full load current of transformer.
           5  Collect the data of total losses of transformer determined by OC & SC test.

           TASK 2 : Connecting and loading of transformer
           1  Make the connection of transformer with all meters and lamp load.

           2  Check the connections and connect HV winding of transformer to the supply.
           3  Switch ON the supply and record the reading of voltmeter, ammeter and watt meter on HV & LV side.
           4  Close the load switch on LV side and increase the load step by step until full load current of  transformer.
           5  Record the reading of voltmeter, ammeter and watt meter at each steps.

           6  Connect the inductive load on the transformer and repeat the steps 2 to 5.
           7  Switch OFF the supply, disconnect the circuit & transformer.











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