chapter 9b - motor

7/29/2019 Chapter 9b - Motor

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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


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


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


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


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

chapter 9b - motor

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