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ELECTRICIAN - CITS



           EXERCISE 49 : To measure high current & voltage using

                                      CT and PT

           Objectives

           At the end of this exercise you shall be able to
           •   check and identify the different types of CT’s & PT’s, and their ratio’s & ratings.
           •   test the polarity of CT & PT and marking the terminals.
           •  measure the high voltage & current with CT & PT.
           Requirements

           Tools/Equipments/Instruments
           •   Combination plier (165mm, insulated)  - 1 No.   •   CT (Demo type) (30/1 A)        - 1 No.
           •   Screw Driver (150mm)             - 1 No.        •   PT (Demo type) (440/110 V)     - 1 No.
           •   Neon Tester (75mm, 500 V)        - 1 No.        •   Current injection kitj (0-50A)   - 1 No.
           •   Electrician knife (Insulated)    - 1 No.        •   Voltage injection kit (0-600 V)   - 1 No.
           •   Voltmeter (MI, 600 V)            - 1 No.        Materials/Components
           •   Voltmeter (MI, 150 V)            - 1 No.        •   PVC copper connecting
           •   Ammeter (MI, 30 A)               - 1 No.           probes (2.5 sq.mm)              - 5 Nos.
           •   Ammeter (MI, 5 A)                - 1 No.        •   Test lamp (100 W, 230V)        - 1 No.
           •   Multi meter (Digital, 3  digit)   - 1 No.
                                 1/2
            Procedure


            TASK 1 : Identify the terminal of CT & PT
           1  Collect the Tools, equipments and materials required for experiment.
           2  Draw the connection diagram of CT and PT.
           3  Check the type, construction, voltage & current ratio of CT and PT.
           4  Check & identify the polarity of terminals of CT and PT, and mark the terminals as

               Primary- P1 & P2
               Secondary- S1 & S2
           5  Check the connection and rating of current injection kit & voltage injection kit.
              Note:  1  For practical experiment purpose use only demo CT & PT’s
                         2  Never test the High tension CT & PT’s which are tested only under expert supervision.




           TASK 2 : Connect and test the CT
           1  Make the connection of primary terminals P1 & P2 of CT in series with current injection kit.
           2  Make sure that current injection kit is OFF and its knob is at zero position.

           3  Connect the secondary terminals S1 & S2 of CT to the ammeter of low range.
           4  Switch ON the current injection kit and gradually increase the CT primary current until CT secondary current
              reaches 1 Amp.
           4  Note down the primary current and secondary current







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