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ENGINEERING TECHNOLOGYManufacturing > Communication > Transportation and Power > Construction > Industrial Design
Prepared by:Engineering Technology TeachersUnit Kurikulum, Jabatan Pelajaran Perak.
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ENGINEERING TECHNOLOGYManufacturing > Communication > Transportation and Power > Construction > Industrial Design
LEARNING OUTCOME
MOTOR AND GENERATORSAIN PAGE
DIFFERENCES BETWEENMOTOR AND GENERATORS
DC MOTOR TYPES
MOTOR AND DCGENERATOR PARTS
DC GENERATOR TYPES
AC MOTOR TYPES
MOTOR & GENERATOROPERATING PRINCIPLES
AC GENERATORTYPES
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STUDENTS SHOULD BE ABLE TO:
1. Describe the functions of motors and generators
2. Label the major parts of motors and generators
3. List types of motor and generator
4. Explain the principles of motors and generators
LEARNING OUTCOME
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DIFFERENCES BETWEEN
MOTOR AND GENERATORS
MACHINES TASKS EXAMPLE OF USE
Motor
Converts electrical energy into
mechanical energy
Uses electricity
Car starter
Lift pulley
Fan
Drive for CD player
Escalator
Generator
Converts mechanical energy into
electrical energy
Produces electricity
Bicycle dynamo
Portable generator Battery charger in a car
Power station
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DIRECT CURRENT MOTOR (DC)1. When the current flows through a wire, a magnetic
field exist around the wire.
2. When the wire is positioned inside a magnetic field, it
will be pushed upwards and downwards according tothe direction of the current and the magnetic polarity.
3. If this wire is wound on an armature, the armature will
rotate.
4. The armature rotating principles is used in most DCmotor.
MOTOR OPERATING PRINCIPLES
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ALTERNATING CURRENT MOTOR (AC)1. An AC motor armature is called a rotor
2. Usually, a rotor has conductor in the shape of a squirrel cage.
3. When a 3-phase AC supply connected to a 3-phase stator, arotating magnetic field is produced.
4. This rotating magnetic field tends to induce an electromotive forceinto the rotor.
5. This causes current to flow within the rotor conductors. The rotor
produces its own magnetic field.
6. It is the interaction of the rotating magnetic field and the rotor'smagnetic field which will cause the rotor to turn.
MOTOR OPERATING PRINCIPLES
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GENERATOR OPERATING PRINCIPLESEMF (Electric Motive Force) can beproduced when the wire cut across the
magnetic or the reverse situation.
Number of EMF depends on:
a. flux (magnetic field)
b. number of conductor/wire
c. number of pole
d. Cutting speed
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a. In principles, there is no difference between motor
and a generator.
b. Motor can function as a generator and vice versa.
c. But there is a slight difference in the construction
of motor and generator. They are divided into three
main parts :
Armature
Magnetic Pole
Connection Source
MOTOR AND DC GENERATOR PARTS
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1. AMARTURE
2. MAGNETIC POLE
3. CONNECTION SOURCE
(USE COMMUTATOR)
MAIN PARTS OF MOTOR & DC GENERATOR
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1. ARMATURE
The rotating part of the DC motor/generator.
Located in the middle section of a machine.
It is constructed from layers of cylindrical and groove
ferrous metal sheets.
The grooves will be coiled with copper wires plated withlacquer.
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2. MAGNETIC POLES
The most important component in a motor andgenerator.
The poles are constructed in pairs and are installed inthe stator.
The magnetic field strength increases the machineefficiency.
The speed of the motor will increase and the outputvoltage produced by the generator will increase as well.
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3. CONNECTION SOURCES
A connection source is a connection place forthe conductor at the armature depending on thetypes of supply.
DC motor the connection sources at the armature, uses a
commutator.
AC motorthe connection source assembles at the stator.
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DC generator Connection source is built at
the commutator
AC generator
Connection source is built atthe slip ring
Commutator
Slip Ring
Armature
Brush
Magnetic Poles
BrushArmature
Magnetic Poles
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MOTOR TYPES
Motor used DC supply is called direct current motor (DC)
Motor used AC supply is called alternating current motor
(AC)
Motor can be operated by using either a DC or an AC
supply is called a universal motor
MOTOR
DC MOTOR AC MOTOR
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DC MOTOR
SERIES MOTOR
COMPOUND MOTOR
SHUNT MOTOR
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1. SERIES MOTOR
CONNECTIONSeries field wounding
USAGEUsed for work that needs high
torque such as a car starter
CHARACTERISTICSHas a small amount of coils
Has wires which are coarse
Has high torque
Will be damaged if run without load
because of its very high speed
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2. SHUNT MOTOR
CONNECTIONHas shunt windings
Its field winding is connected parallel
the armature
USAGEUsed for work that needs
constant speed such as a lathe
CHARACTERISTICSHas fine wire coils
Has large amount of windings
Has constant speed with or without load
Can be driven without load
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3. COMPOUND MOTOR
CONNECTIONCombined serieswinding and shunt
winding
USAGEIs suitable for all types of work,
especially those that need high torque
but are continuous such as a lift
CHARACTERISTICSHas fine wire coils
Has large amount of windings
Has constant speed with or without load
Can be driven without load
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AC MOTOR
REPULSIVE MOTOR THREE-PHASE
INDUCTION MOTOR
UNIVERSAL MOTOR
SINGLE- PHASE
INDUCTION MOTOR
SYNCHRONOUS
MOTOR
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Operation Principle Assemblance Usage
Single phase AC supply
Produces mutual induction at the
rotor.
The magnetic field rotation at the
stator pushes the magnetic field
at the rotor.
A manipulator is
connected to a
commutator
The source of
end-connection
at the rotor is
crossed.
Light work.
Electric fan.
1. REPULSIVE MOTOR
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2. SINGLE-PHASE INDUCTION MOTOR
Operation Principle Assemblance Usage
Single phase AC supply, produces
mutual induction at the rotor.
A supply phase is divided into two
to allow the magnetic field torotate at the stator.
The magnetic field rotation at the
stator is followed by the rotor.
Coil at the
stator
A squirrel cage
rotor
Some have
centrifuge
switches &
capacitor
Induction
actuator
induction
starter
Electric fans
Grinding
machines
Vacuumcleaners
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3. THREE-PHASE INDUCTION MOTOR
Operation Principle Assemblance Usage
Three-phase AC supply
Produces a rotatingmagnetic field at the
stator & a mutual
induction at the rotor.
The rotor rotation followsthe magnetic field rotation
at the stator.
3 sets of coils at the
stator.
Squirrel cage rotor More powerful than
single-phase motor
Light work.
Air-cond
Water pumps Air pumps
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4. SYNCHRONOUS MOTOR
Operation Principle Assemblance Usage
3-phase supply.
The rotor is supplied with DC.
The rotors rotational speed is
the same as the magnetic fields
rotational speed at the stator.
3 sets of coils at
the stator.
Its rotor is
installed with
squirrel cage
rotor and a
manipulator.
Central air
conditioning,
generator
drives.
Continuous
work at
constantspeed.
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5. UNIVERSAL MOTOR
Operation Principle Assemblance Usage
Single Phase supply.
Both fields interact to produce
rotation.
The stator is
connected in
series to the
rotor.
Rotor winding
coil
Uses acommutator.
Portable
drills
Food
processors
Vacuum
cleaner
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GENERATOR TYPES
Generator is differentiated by the way it generates
electricity.
A generator that produces an AC supply is called an
alternator
A generator that produces DC generator retains the
name generatorGENERATOR
DC GENERATOR ALTERNATOR
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DC GENERATOR
SERIES GENERATOR
COMPOUND GENERATOR
SHUNT GENERATOR
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1. A SERIES GENERATOR
CHARACTERISTICS
Generates voltage after
electric load is connected to its
output.
The value of voltagegenerated depends on load
current.
A seriesgenerator
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2. A SHUNT GENERATOR
CHARACTERISTICS
Its voltage is generated
even without electric load
The value of voltage
generated is nearly constantA shuntgenerator
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3. A COMPOUND
GENERATOR
CHARACTERISTICS
Combines the series and
shunt electrical circuits.
Two compound generator,
i.e. long shunt compoundgenerator and short shunt
compound generator.
A compoundgenerator
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GENERATOR TYPES
Generator is differentiated by the way it generates
electricity.
A generator that produces an AC supply is called
an alternator
A generator that produces DC generator retains thename generatorGENERATOR
ALTERNATORDC GENERATOR
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A generator that produces an AC supply is called an
alternator.
In general, there are two types of alternator :
Stationary Field
A Stationary Armature
ALTERNATOR
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END OFCHAPTER 9B