Page 191 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

MODULE 6 : DC Generator and DC Motor

LESSON 30-37 : DC Generator Principle - parts - types -

function e.m.f equations, charactrics of D.C

Objectives
At the end of this lesson you shall be able to:
• state the principle of the D.C. generator
• expain the faraday’s of laws of electromagnetic induction
• describe the parts of a DC generator & their function
• classity & identify the different type of generator
• drive the e.m.f equations, charactrics of D.C generator
• explain the operation of parallel of D.C generator

Principle of dc generator operation
Faradays laws of electromagnetic induction
First law:
Whenever the magnetic flux linked with a circuit changes, an e.m.f. is always induced in it.
Whenever a conductor cuts magnetic flux, an e.m.f. is induced in that conductor.
Second law:
The magnitude of the induced e.m.f. is equal to the rate of change of flux linkages.
Requirements for dc generator
• Magnetic field
• A conductor
• A mechanical driving force as prime mover
Generation of AC
1 A coil moves in a magnetic field
2 Coil is connected to slip rings
3 Brushes connect the load R to the slip ring
A The maximum emf is induced when the coil is perpendicular to the magnetic field.
B The minimum emf is induced when the coil is parallel to the magnetic field

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