Page 66 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

MODULE 5: Magnetism, AC Circuits

EXERCISE 26 : To prepare an Electromagnet and Testing

Objectives

At the end of this exercise you shall be able to
• wound the bare copper conductor on plastic bobbin
• make the electro magnet and test the magnetic property
• test the polarity of electromagnet by magnetic needle
• vary the strength of magnetic field of electromagnet.

Requirements

Tools/Equipments Materials
• Combination Plier (150 mm, insulated) - 1 No. • Bare copper conductor 26 SWG - 4 Mtr.
• Nose plier (100mm, Insulated) - 1 No. • Hook up wire Single strand - 0.5 Mtr.
• Connector screw driver 100 mm - 1 No. • Soldering lead - as reqd.
• Electrician knife insulated - 1 No. • Soldering flux - as reqd.
• Soldering iron 25 W, 230 V - 1 No. • Plastic /paper bobbin (Any small size) - 2 Nos.
• Neon tester 75mm, 500V - 1 No. • Steel bolt 8mm X 50mm - 1 No.
• Magnetic needle - 1 No.
• DC power supply 0-100V - 1 No.
• Auto transformer 0-250 V AC - 1 No.

Procedure

TASK 1 : Construction of Electromagnet
1 Take the plastic bobbin and fix it vertically on wooden board.

2 Fix the nail tightly adjacent to the plastic bobbin.
3 Take one end of bare copper conductor and twist it tightly on the nail.
4 Now start winding of bare copper conductor uniformly on plastic bobbin.
5 Make a coil of around 100 turns and wrap the insulating paper tightly on the coil.

6 Remove the coil winded bobbin from wooden board.

TASK 2 : Testing the Electromagnet with DC supply
1 Fix the coil winded bobbin horizontally on wooden board.

2 Make the end connection of coil terminals with hook up wire by soldering and insulate properly.
3 Insert the metal bolt into the bobbin with soft spring support.
4 Now Electro magnet is ready for testing, and connect its terminals to DC power supply.
5 Switch ON the DC power supply and slowly apply the voltage about 12 V
6 Check & observe the magnetic property of Electromagnet by touching with metal object.

7 Check the polarity of Electromagnet with magnetic compass needle.
8 Switch OFF the DC power supply and disconnect the electromagnet.

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