Page 116 - CITS - Electrician - Trade Practical
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ELECTRICIAN - CITS




           TASK 3 : Connect and verify the voltage of 3 Ph. Auto transformer
           1  Connect the primary input terminals (R S T) of 3 Ph. Auto transformer to 3 ph. Mains, and set its knob to zero
              position.
           2  Connect the voltmeter across secondary output terminals (U V W)
           3  Switch ON the main supply and measure the primary input line voltage & record.
           4  Slowly rotate the knob clockwise and measure the variable 3 Phase output voltage across secondary terminals.

           5  Increase the voltage step by step and record the output voltage until last taping of winding.
           6  Reduce the voltage to zero and switch OFF the supply & disconnect the auto transformer.
                                                     Tabular column:

                                           Primary Input Voltage   Tapping No. Secondary Output Voltage (V )
                                                    (V )                                                   S
                                                      P
            1 Ph. Auto Transformer        1 Ph. 230 V              1

                                                                   2
                                                                   3

                                                                   4

            3 Ph. Auto Transformer        3 Ph. 415 V              1
                                                                   2

                                                                   3

                                                                   4






















              Safety precautions:
              1  Handle the auto transformer carefully as it is heavy.
              2  Select higher range in voltmeter while measuring 3 Ph. voltage
              3  Set knob to zero position before switching ON the auto transformer.
              4  Ensure the earthing for auto transformers.













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                                    CITS : Power - Electrician & Wireman - Exercise 48
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