Transcript Salient Pole Rotor type

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Ramavat Nikunj (140543111003)
Outlines:
 Introduction
 Construction
 Working principle
 Types of Synchronous Machine
 Comparison between cylindrical rotor
type alternator and Salient pole rotor
type alternator

A synchronous machine is an AC machine whose
speed is proportional to the frequency of
armature current.

A machine which rotates at a speed fixed by the
supply frequency and the number of rotor poles
is called synchronous machine.

It always runs at synchronous or constant speed
and has no slip.

Synchronous machine includes synchronous
generators and synchronous motors.
 An
alternator cosists of two main parts;
 1) Stator and
 2) Rotor
Stator: The
stator is the stationary parts part of the
alternator .
 It works as a armature in synchronous
machine.
 The armature winding is housed in it.
Rotor:
 Rotor
is the rotating part of the synchronous
machine.
 It work as a field of the synchronous
machine.
 Field system is rotating in the synchronous
machine.
 Field winding is housed on it.
 Field winding is excited by DC supply through
brushes and slip ring.
 It
works on the principle of Electromagnetic
induction
 In the synchronous generator field system is
rotating and armature winding is steady.
 Its works on principle opposite to the DC
generator
 High voltage AC output coming from the
armature terminal

Synchronous generators are classified in two
category according to its rotor construction:


1) Cylindrical Rotor Type
2) Salient pole rotor type.

Cylindrical Rotor Type:-



This type machines are High speed machines.
(1000 to 3000 RPM)
This type machine has Small diameter and is
large axial length.
This type of machines are used in Thermal power
plant and gas turbine power plant. Where speed
requires high.
 Salient




Pole Rotor type
Salient Pole rotor type machine:
This type machines are Low speed
machines.(50 to 500RPM)
This type machine has Large diameter and
is small axial length.
This type of machines are used in Hydro
power plant. Where speed are very low.
Cylindrical rotor:
Cylindrical rotor does not have poles that are projecting out.

The air gap between the stator and rotor is uniform.

The smooth cylindrical rotor has small no of poles.

Cylindrical rotors are mechanically strong.

They have small diameters and large axial length.

The prime movers used are steam turbines and electric motors.

They are preferred for high speed alternators which range from
1000 to 3000 RPM
Salient Pole rotor:
Salient pole rotor does have poles that are projecting out from
surface.

The air gap between the stator and rotor is non-uniform.

The salient pole rotor has large no of poles.

Saline Pole rotors are mechanically weak.

They have large diameters and small axial length.

The prime movers used are IC engines and law speed turbine.

They are preferred for high speed alternators which range from
50 to 500 RPM
Thank you !