Page 74 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

TASK 3 : Apply STAR & DELTA connection in AC machines
1 STAR & DELTA connection is applicable in AC 3 ph. Supply system and 3 ph. AC machines like Transformer,
Alternator, induction motor.

2 Take 3 ph. Induction motor and connect in STAR fashion.
3 Apply 3 ph. Supply through TPST switch and record line & phase voltage and line & phase current.
4 Similarly, connect the motor in DELTA fashion and record line & phase voltage and line & phase current.
5 Switch OFF the supply and disconnect the motor.
6 Calculate the line & phase voltage and line & phase current as per Star Delta equations.

Safety precautions:
1 Follow the correct sequence in STAR and DELTA connection.
2 Never connect single bulb in the circuit, instead connect 2 bulbs in series.
3 Do not make joints and loose connections.

4 Select proper range in voltmeter & ammeter.
5 Ensure proper earthing to TPST switch and induction motor.
Tabular column:
Line voltage (V ) Phase voltage (V ) Line current (I ) Phase current (I )
Connection L PH L PH

STAR
DELTA

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CITS : Power - Electrician & Wireman - Exercise 29