Click to edit Master title style

ELECTRIC MOTOR
B Y : H O N E Y L E T T E TAY O N G

1
Click to edit Master title style

Objectives;
discuss how an electric motor work;

explain the operation of a simple

electric motor; and

differentiate a DC from AC motor.

2 2
Click to and
History editDevelopment
Master title style
of Electric Motors
Insert image

Peter Barlow Joseph Henry Frank Julian Sprague

Anyos Jedlik Moritz Hermann Jacobi Nikola Tesla

3 3
Peter
Click to Barlow
edit Master title style

He invented the very first rotating device in 1822 known as Barlow’s Wheel

Barlow’s Wheel - a freely rotating spiked wheel connected to a power source surrounded
by a magnetic field from a horseshoe magnet

Peter Barlow and his invention of a motor in the form of a rotating device. 4 4
Anyos
Click Jedlik
to edit Master title style

He is the first one to invent a commutated rotary machine with magnets in 1828.

Anyos Jedlik and his invention of a motor

5 5
Joseph
Click Henry
to edit Master title style

He was able to build an oscillating electromagnetic motor in 1831 that he regarded as a

“philosophical toy” - the first demonstration of continuous motion produced by magnetic
attraction and repulsion

Joseph Henry and his oscillating electromagnetic motor called as the “philosophical toy”
6 6
Moritz
Click Hermann
to edit Jacobi
Master title style

He built the first “real” motor in 1834

Jacobi’s motor was the first motor to deliver a remarkable mechanical output power

Moritz Hermann Jacobi and his electric motor

7 7
Frank
Click to Julian Sprague
edit Master title style

He invented the first practical motor in 1886

his motor was a non-sparking motor that maintained relatively constant speed under
variable loads
Frank Julian Sprague and his version of an electric motor.
8 8
Nikola
Click Tesla
to edit Master title style

He developed a three-phase system in which instead of only a single magnetic field

acting on a coil of wire is present, three rotating magnetic fields will act on coils of wire
causing it to produce mechanical energy

Nikola Tesla and his induction motor

9 9
Click to edit Master
Current-carrying title
Wire style
and Galvanometer

Hans Christian Oersted

The production of a magnetic field by a current-carrying wire was first noted by Hans
Christian Oersted in 1820 during one of his lectures.

Oersted placed a compass near a wire connected to a battery. When the switch is turned on, the
compass needle deflects as the current flows through the wire. This shows that electric current
1010
generates magnetic field.
Current-carrying
Click Wire
to edit Master title styleand Galvanometer

no current flow with current flow

1111
Maxwell’s
Click Right-Hand
to edit Master Grip
title style Rule

One convenient rule in remembering the direction of magnetic field in a current carrying
wire is the Maxwell’s right hand rule.

When you point your right thumb in the direction of the current, the direction of the
magnetic field is the direction of the curl of the remaining four fingers.

Maxwell’s Right-Hand Grip Rule

1212
Galvanometer
Click to edit Master title style

• A galvanometer is a
current-detecting device
that uses a stationary
magnet mounted with
moving coil attached to
a needle. The greater the
current present in the
wire, the larger the
deflection of the needle.
1313
Galvanometer
Click to edit Master title style

• The coil of the

galvanometer rotates as
current passes through
it. A pointer attached to
it also moves whenever
the coil rotates. If there
is no current flow, the
coil and pointer are kept
at zero position by a tiny
spring. 1414
Electric
Click Motor
to edit Master title style

• It converts electrical energy

into mechanical energy.

• The major difference

between a galvanometer and
a motor is that current in an
electric motor reverses
direction each time the coil
turns half-way.
1515
Click to edit
Fleming’s Master title
Left-hand Rulestyle
for Motors

• Thumb = direction of force

• Index finger = direction of

magnetic field used to identify the direction of movement of the
current-carrying wire if placed in a magnetic
• Middle finger = direction of field
current 1616
Example:
Click to edit Fleming’s Left-hand
Master title style Rule for Motors
• The figure shows that
the flow of the current is
from the battery →
conducting brush X →
split ring P → arm AB
→ arm CD →
conducting brush Y →
split ring Q.
1717
 Applying
Click Fleming’s
to edit Master Left-hand
title style Rule for Motors

The next figure shows the location of the parts of the

electric motor after half rotation of the coil.
1818
 Applying
Click Fleming’s
to edit Master Left-hand
title style Rule for Motors

Notice that the location of arm AB and CD is reversed.

Also, the split ring Q now touches the brush X and the split ring P now touches the brush
Y. This means that the flow of the current will be reversed after the half rotation.
1919
Click to Applying
edit Master title style
Fleming’s Left-hand Rule for Motors
The current flow will be
from D → C → B → A. in
effect, the reverse current
flow will also reverse the
force acting on the arms AB
and CD.

Thus, after the half rotation,

the arm AB which
previously pushed
downwards will now be
pushed upwards and the
arm CD which is previously
pushed upwards will now
be pushed downwards.
2020
 Applying
Click Fleming’s
to edit Master Left-hand
title style Rule for Motors

Therefore, the reversing of the

current occurs every half rotation
which creates a continuous
rotating motion of an electric
motor.
2121
Click
DC to AC
and edit Master title style
Motors

DC motors are powered by direct current AC motors do not use brushes and commutators.
sources like batteries. Unlike a DC motor, an AC motor has a rotating
magnetic field and a stationary armature.
In this type of motor, the coil of wire rotates
while the magnetic field (produced by It also has a longer lifespan and is usually utilized
magnets or electromagnets) stays in one when there is a need for power at an extended period
direction. of time.
DC motors are commonly used in applications
where motors need to be externally controlled. 2222
Let’stoRemember!
Click edit Master title style

A galvanometer is a current-detecting device that uses a stationary

magnet mounted with moving coil attached to a needle.

Electric motors convert electrical energy to mechanical energy.

Maxwell’s right-hand grip rule shows the direction of current and

magnetic field. When you point your right thumb in the direction of
the current, the direction of the magnetic field is the direction of the
curl of the remaining four fingers. 2323
Click
Let’stoRemember!
edit Master title style

Fleming’s left-hand rule There are two types of motors

• is used to identify the DC motors are commonly

direction of movement of used in applications where
the current-carrying wire if motors need to be externally
placed in a magnetic field. controlled.
AC motors are usually
utilized when there is a need
for power at an extended
period of time.
2
24
Read and
Click to analyse
edit Masterthe
titlefollowing
style statements given. Write
true if the statement is correct and false if incorrect.

A galvanometer DC motors are Peter Barlow DC motors do He said that

is a device that usually utilized invented the not use three rotating
measures the when there is a very first brushes and magnetic fields
presence of need for power rotating device commutators. will act on coils
magnetic field. at an extended in 1822. of wire causing
period of time. it to produce
mechanical
2525
energy
Read and
Click to analyse
edit Masterthe
titlefollowing
style statements given. Write
true if the statement is correct and false if incorrect.

He is the first He was able A compass The direction The reversing of

one to invent to build an works by of the the current occurs
a commutated oscillating detecting the current is in every half rotation
rotary electromagnet Earth’s which creates a
the index continuous
machine with ic motor in natural
finger. rotating motion of
magnets in 1831 magnetic
1828. fields. the magnetic field.
2626
ESSAY
Click to edit Master title style

Why does a compass

needle move?

2727
Click to edit Master title style

“
I hope that my heart works like the
galvanometer which can detect current so if
I met someone I can detect it if he’s the one.

- Anonymous

2828
Click to edit Master title style

Thank You

Roxas! 

29
Click to editthis
Customize Master title style
Template

Template Editing Instructio

ns and Feedback

3030