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ELECTRICIAN - CITS

EXERCISE 57 : To design & construct decorative light

Objectives

At the end of this exercise you shall be able to:
• design the decorative light circuit for given supply voltage
• select the appropriate bulbs and construct the decorative light
• test and repair the decorative lights.

Requirements

Tools/Equipments/Instruments Materials/Components
• Combination Plier 165mm, • Flexible copper wire 1.0 sq.mm -1 Coil.
insulated -1 No. • Test lamp 100 W, 230V -1 No.
• Connector screw driver 100 mm -1 No. • Screw cap bulb 6 V, 100 mA -50 No’s.
• Neon Tester 75mm, 500 V -1 No. • Screw type lamp holder 6 V, 100 mA -50 No’s.
• Electrician knife Insulated -1 No. • Soldering lead -1 role.
• Soldering iron with stand • Soldering flux Resin core -as reqd.
25 W, 230 V -1 No.
• Multi meter Digital, 3 digit -1 No.
1/2

Procedure

TASK 1: Designof decorative lights
1 Draw the circuit diagram of series & parallel connection of serial lights / decorative lights.
2 Check the type and voltage rating of decorative serial lamps.

3 Design / calculate the No. of bulbs required for given supply voltage and type of connection.
Calculation:
Supply voltage = 230 V
Rated voltage of decorative lamp = 6 V
No. of lamps required = 230 = 38 lamps

6
Add 5% voltage fluctuation - 38 + 5% of 38 = 1.9
= 38 + 1.9 = 39.9 (say 40 lamps)
40 No’s of 6 V lamps to be connected in series for one group of circuit.

Make 3 OR more groups and connect all the groups in parallel to increase the No. of lamps in decorative serial
lights.

TASK 2: Construction of decorative lights
1 Cut the PVC flexible wire into pieces as per required No. and lengths.
2 Remove the insulation of flexible wire pieces and make a tinning with soldering.
3 Make the tinning on the terminals of 40 No’s of 6V screw type lamp holders.

4 Now connect all 40 No’s of screw type lamp holders in series with a flexible wire pieces by soldering.
5 Insert the 6V bulbs in lamp holders properly.
6 Connect the flasher in series with decorative serial lamp circuit.

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