Level 2 physics: Brushless motors research assignment
The motor effect
Info -Source Information from source Ke ywords My own words/interpretation
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-forces/m
otor-effec
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When two magnets are placed
close to each other, the
magnetic fields affect each
other produce a force
If a wire carrying a current is
placed inside this magnetic
field, a force is produced.
This is called the motor effect
The direction of the force will
depend on the direction of the
magnetic field and the direction
of the current in the field
Magnets
Direction
Magnetic
Current
Force
A force is produced when two
magnets are placed close enough
together, this force created is a
Ma gnetic field.
If you were to place a wire in this
magnetic field, you will find
another force is produced. This is
called the motor effect.
The magnetic field dictates the
direction of the force and the
direction the current in the field will
travel
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The direction of the force –
and therefore the
movement of the wire – can
be determined using
Fleming’s left hand rule.
Direction
Movemen
t
Force
Field
The motor effect occurs when a
coil is charged with a current,
this same coil will now
experiences a force and moves
with the current. Building a
simple electric motor can be as
simple as using a coil of wire free
to rotate around two magnetic
poles.
Remember:
● thu M B – M ovement
● F orefinger – magnetic
F ield
● se C ond finger – C urrent
The force's direction is reversed
if either the direction of the
magnetic field is reversed or the
direction of the current is
reversed.
Advantages and Disadvantages of Brushless dc motors
http://m
buynow
.blogsp
ot.co.nz
/2013/0
5/whatr
e-adva
ntagesand-
dis
advant
ages-of
.html
Advantages:
Brushless motors offer several
advantages over brushed DC
motors, including high torque to
weight ratio, more torque per watt
(increased efficiency), increased
reliability, reduced noise, longer
lifetime (no brush and commutator
erosion), elimination of ionizing
sparks from the commutator, and
overall reduction of electromagnetic
interference (EMI).
Efficient
Torque
Ionizing
EMI
Commutator
Some of the advantages
when it comes to brushless
motors include that,
compared to a brushed dc
motor, a brushless dc motor
has a higher torque to weight
ratio, and a higher torque per
watt ratio.
Brushless motors also have
the advantage of noise
reduction and a longer
lifespan due to the non
contact technology
http://m
buynow
.blogsp
ot.co.nz
/2013/0
5/whatr
e-adva
ntagesand-
dis
advant
ages-of
.html
http://w
ww.ele
ctrical4
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brushle
ss-dcmotors/
Disadvantages:
For most people who have
brushless motor will say brushless
motor is expensive. That’s true. But
have you think about what cause
the problem. Brushed motors are
cheap to produce, but the brushes
wear out from rubbing against the
contact point and axle. Friction
from this contact also impedes
performance. For brushless motor,
as it appeared later than brushed,
regardless of technology or
materials, there are big challenges.
Also, electric controller is required
to keep the motor running. It offers
double the price of the motor.
The limited high power could be
supplied to BLDC motor,
otherwise too much heat weakens
the magnets and insulation of
winding may get damaged.
Expensive
Performance
Controller
Affordable
Quality
Friction
The main disadvantage of
brushless motors would have
to be the price. Because of
the cost of the components
and the delicate assembly of
the brushless dc motor.
Electric controllers are also
used in brushless dc motors,
boosting the price even
higher. The electric
controllers are required to
keep the motor running.
Another disadvantage of
brushless dc motors are the
high power supplied to the
the motor. The heat tends to
weaken the magnet and
could cause damage to the
internals of the brushless
motor.
Why brushless motors are used in computers
https://ww
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CPU
Mostly in CPUs Motors are
used to run the Fans used
for cooling the processors
and Power supply units.
It will be enough to say that
we will see motors are used
only in the cooling systems
of CPUs.
Brushless DC Motors are
used. Brushless Motors are
super quiet (Due to absence
of brushes) and they have
higher speeds than Brushed
DC Motors.
Processors
Power
Supply
Cooling
Brushed
Brushless
Brushless motors are used to run
the fans that have the job of
cooling the computers
processors and the main power
supply unit.
These brushless motors are
commonly only used in the
cooling system of a computer's
cpu (central processing unit)
http://www.
pcbheaven
.com/wikip
ages/How_
PC_Fans_
Work/
The vast majority of PCs
has at least one of them.
They carry the heavy load to
keep your PC cool and
functional, either by
providing fresh air in the
box, or by forcing the hot air
to leave a hot surface by
pushing cool air.
As long as the motor is
concerned, i suppose that
all PC fans use brushless
motors. There are several
reasons that a brushless
motor should be used,
among them is the
reliability, the power
efficiency and the rpm
feedback
Functional
Reliability
Efficiency
Rpm
Feedback
Brushless
Another key reason brushless
motors are used in personal
computers are the fact that they
are built to carry the heavy load
of current needed to keep your
pc cool and functioning. This
process is carried out by either
providing fresh air into the box or
by forcing the hot air out of the
box, off of a hot surface.
The reliability of a brushless
motor is also a key reason they
are used in personal computers,
making maintenance of the fan
necessary. The reliability of a
computer fan is also important,
because if the fan were to stop
working it would overheat the
computer's cpu and damage
your pc, whilst also posing a fire
hazard.
Brushless motors and how they differ from a brushed motor.
Brushed
Motors
https://e
n.wikipe
dia.org/
wiki/Bru
shed_D
C_electr
ic_motor
A brushed DC motor is an
internally commutated electric
motor designed to be run from a
direct current power source..
Brushed DC motors can be varied
in speed by changing the operating
voltage or the strength of the
magnetic field. Depending on the
connections of the field to the
power supply, the speed and
torque characteristics of a brushed
motor can be altered to provide
steady speed or speed inversely
proportional to the mechanical
load .
Commutate
d
Direct-
Current
Varied-
Speed
Operating-
Voltage
Magnetic-
Field
Proportional
Inversely
Mechanical
To know the difference between a
brushed dc motor and a
brushless motor, you first have to
know how each of them operate.
This will clearly show the
difference between the two types
of motors:
A brushed dc motor is designed
to run from direct current as its
power source. This means that
the speed of a brushed motor can
be varied by changing the
magnetic field or the voltage used
in the motor.
A brushless motor however is
designed to rotate around a fixed
armature using the magnets
which are permanently fixed.
Brushless motors are designed
this way to avoid problems
caused by the current connecting
to the moving armature. However
brushless motors don’t have a
brush communicator incorporated
into their design, instead the
motor is kept running using a
device called the electronic
controller, which changes the
phase of the winding regularly in
an effort to keep the motor
turning.
In conclusion, brushed and
brushless motors differ in the
sense that the brushless motor is
powered by AC current signal
received by the drive motor. Also
that Brushed motors are
controlled by changing the
https://e
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dia.org/
wiki/Bru
shless_
DC_elec
tric_mot
or
A typical brushless motor has
permanent magnets which
rotate around a fixed armature ,
eliminating problems associated
with connecting current to the
moving armature. An electronic
controller replaces the
brush/commutator assembly of
the brushed DC motor, which
continually switches the phase
to the windings to keep the
motor turning.
The controller performs similar
timed power distribution by
using a solid-state circuit rather
than the brush/commutator
system.
Brushless
Permanent
Armature
Current
Electronic
Controller
Switches
Distribution
Circuit
voltage where as the brushless
motor is controlled by an
electronic controller.
Key words used when explaining brushless motors:
Armature
https://en.wikipedia.org/wiki/
Armature_(electrical_engine
ering)
In electrical engineering , an
armature generally refers to
one of the two principal
electrical components of an
electromechanical or
electrical machine —
generally in a motor
The armature within a motor
refers to the conductive coil
within a motor that carries
current. This creates torque in
a spiraling shaft causing the
rotation inside the motor
Commutator
https://en.wikipedia.org/wiki/
Commutator_(electric)
A commutator is a moving
part of a rotary electrical
switch in certain types of
electric motors and electrical
generators that periodically
reverses the current direction
between the rotor and the
external circuit.
In a motor the commutator
serves to supply the motor
current to its windings. A steady
amount of rotating torque is
produced when you reverse the
direction of the current through
each half turn of a winding.
Electronic controller
https://en.wikipedia.org/wiki/
Electronic_speed_control
An electronic speed control
or ESC is an electronic circuit
with the purpose to vary an
electric motor 's speed, its
direction and possibly also to
act as a dynamic brake . often
used for brushless motors
essentially providing an
electronically generated
three-phase electric power
low voltage source of energy
for the motor.
An electronic controller serves
to adjust the motor's speed
according to the phase of the
motors winding.
While also proving the motor
with a source of three-phase
low voltage power.
Torque
https://en.wikipedia.org/wiki/
Torque
Torque , moment , or
moment of force (see the
terminology below) is the
tendency of a force to rotate
an object about an axis,
fulcrum, or pivot.
Torque is the force of a
movement, and reflects on an
object’s force of travel circling
an a x is, pivot or fulcrum.
Research task by Lachlan Spargo…