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RE1345 RE1345

KONVERSI TENAGA LISTRIK II KONVERSI TENAGA LISTRIK II

Vita LystianingrumVita Lystianingrum

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RE1345 RE1345 KONVERSI TENAGA LISTRIK IIKONVERSI TENAGA LISTRIK II

1: Klasifikasi mesin-mesin listrik dan konstruksi 2: Generator sinkron: proses terbangkitnya EMF dan macam-macam

generator sinkron 3: Generator sinkron: berbeban, kerugian tegangan, diagram vektor

untuk pf. lagging, pf. leading 4: Generator sinkron: menentukan voltage regulator dengan metode

EMF dan karakteristik 5: Generator sinkron: kerja paralel 6:7: Motor sinkron: metode start dan pengaruh perubahan arus eksitasi 8: Motor sinkron: torque dan contoh soal 9 & 10: UTS

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ReferencesReferences

1. Theraja, B. L., ‘Electrical Technology’, S. Chand & Company Ltd., 1978.

2. Karady, G., ‘Lecture Notes on Synchronous Generator’, www.eas.asu.edu/~karady/360_pp.html.

3. Zuhal

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Review KTL 1:Review KTL 1:DC MachinesDC Machines

• Generators convert mechanical energy to electric energy.

• Motors convert electric energy to mechanical energy.

• Faraday’s Law

-> Dynamically & statically induced.

• The construction of motors and generators are similar.

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DC generatorDC generator

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DC generatorDC generator

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carbon brushes

DC Motor DC Motor PartsParts

Field magnet

stator

rotor

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AC Generator

http://www.walter-fendt.de/ph11e/generator_e.htm

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DC Generator: AC Generator with Commutator

http://www.walter-fendt.de/ph11e/generator_e.htm

1111

1212

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AC Generators / AlternatorsAC Generators / Alternators

• Same principles as DC generators -> armature winding & magnetic field.

• Armature winding -> statorfield winding -> rotor

**

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Why stationary armature?Why stationary armature?

• Without brush contact->The output current can be led directly from fixed terminals on the stator (armature windings) to the load circuit.

• Easier to insulate stationary armature winding for high AC voltages (may be as high as 30 kV or more)

• Sliding contacts i.e. slip-rings are transferred to the low-voltage, low-power DC field circuit-> easily insulated

• **Armature windings can be more easily braced to prevent any deformation produced by the mechanical stresses

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Stator Rotor

Connections

Bearing

Stator winding

Rotor winding

Housing ,cooling ducts

Shaft

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Stator• Laminated iron

core with slots• Steel Housing

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Stator details• Coils are placed in

slots

• Coil end windings are bent to form the armature winding.

Slots

Coil

End winding

Iron core

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??

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**2 kinds of rotor**2 kinds of rotor

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Round rotor

Steel ring

DC current terminals

Wedges

Shaft

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Rotor Details

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Round rotor

• The round rotor is used for large high speed (3600rpm) machines.

• A forged iron core (not laminated,DC) is installed on the shaft.

• Slots are milled in the iron and insulated copper bars are placed in the slots.

• The slots are closed by wedges and re-enforced with steel rings.

Round rotor

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Round Rotor Machine

• The stator is a ring shaped laminated iron-core with slots.

• Three phase windings are placed in the slots.

• Round solid iron rotor with slots.

• A single winding is placed in the slots. Dc current is supplied through slip rings.

Concept (two poles)

N S

A

-B

+

A

+C

+

C

-

B

-

A

B

CStator with laminated iron-core

Slots withwinding

Rotor with dcwinding

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Salient rotorSalient rotor

• Usually for low- & medium-speed alternators

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Salient Rotor Machine• The stator has a laminated

iron-core with slots and three phase windings placed in the slots.

• The rotor has salient poles excited by dc current.

• DC current is supplied to the rotor through slip-rings and brushes.

• Concept (two poles)

N

S

A+

B+

C+B-

A-

C-

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Construction

• The picture shows the laminated iron core and the slots (empty and with winding).

• The winding consists of copper bars insulated with mica and epoxy resin.

• The conductors are secured by steel wedges.

• In large machines, the stator is liquid cooled.

• The iron core is supported by a steel housing.

• Construction

empty slots

insulated winding

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Salient pole rotor construction

• The poles are bolted to the shaft.• Each pole has a DC winding.• The DC winding is connected to the slip-rings (not shown).• A DC source supplies the winding with DC through brushes

pressed into the slip ring. • A fan is installed on the shaft to assure air circulation and

effective cooling.

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

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SYNCHRONOUS MACHINESSYNCHRONOUS MACHINES

Construction• Low speed, large hydro-

generators may have more than one hundred poles.

-> relationship between speed & poles

• These generators are frequently mounted vertically.

• The picture shows a large, horizontally arranged machine.

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• Thank You, see you next week

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• Different construction of synch. Gen & DC gen ->

• Which one precedes?

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