Page 75 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

MODULE 6: DC Generator and DC Motor

EXERCISE 30 & 34 : To identify the parts of DC Generator

Objectives

At the end of this exercise you shall be able to
• dismantle and reassemble of DC Generator
• identify the parts of DC Generator
• measure the resistance of field coils & armature
• check & identify the terminals of DC Generator.

Requirements

Tools/Equipments
• Combination Plier (165 mm, • Rubber mallet 0.5 kg - 1 No.
insulated) - 1 No. • Old DC compound Generator
• Screw Driver set 150mm, 5 blades - 1 Set 250 V DC - 1 No.
1/2
• Neon tester 75mm, 500V - 1 No. • Multi meter Digital, 3 digit - 1 No.
• Electrician knife Insulated - 1 No. Materials
• Spanner set 6 to 32 mm - 1 Set • Test lamp 60 W, 230 V - 1 No.
• Allen key set 4 to 8 mm - 1 Set • Emery paper - 1 Sheet
• Ball peen hammer 0.5 Kg - 1 No. • Cotton waste / cloth - as reqd.
• Bearing puller - 1 No.

Procedure

TASK 1: Read and note the name plate details of DC Generator
1 Clean the given DC generator with cotton waste.
2 Read the name plate and record the specifications of DC generator
3 Place the DC Generator on wooden table and make a mark on both sides of end covers & yoke.

TASK 2: Dismantling the DC Generator.

1 Unscrew the assembly nut bolts & screws of DC Generator with spanner / Allen key
2 Remove the both side end covers of DC Generator.
3 Disconnect the terminals of field coils, armature.
4 Carefully remove the carbon brushes from the commutator.

5 Carefully take out the armature assembly without damaging field coils.

TASK 3: Identify the parts of DC Generator and reassemble.

1 Identify the parts of DC Generator, viz- Yoke, Armature, commutator, brush, field poles & coils.
2 Measure the resistance of field coils and armature with multi meter.
3 Check the Generator terminals in terminal box.
4 Reassemble the DC Generator properly.
5 Check the mechanical assembly, free rotation of shaft and friction if any.

6 Clean the machine and keep it in proper place.
Safety precautions:
1 Use proper tools for disassembling & assembling the DC Generator.

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