ELECTROMAGNETIC & EDDY CURRENT BRAKING SYSTEMS

Andrew Sponsler
Sean Kurtz
permanent magnet system is unable to hold a body in
place. ECB are excellent at slowing down high speed
moving objects, but just have not been sufficiently
developed to work at lower speeds. This is the main reason
why ECB have not been used in cars, by assumption. The
concept is promising, but there has not been enough research
performed on the subject to find a way to apply the system
to smaller moving bodies or bodies moving at low velocities.
Another significant disadvantage to eddy current brakes
is their studied interference with other signaling and electric
parts of certain applications. Since this system relies heavily
on magnetism, the fields in place by the brakes can alter
other signaling processes. A study involving high-speed
trains showed that several of the signaling grids were
experiencing interference caused by the ECB system’s
generated magnetic field, even while the ECB system was in
the off position [8]. The permanent magnets involved in
ECB may potentially pose hazards to sensitive medical
equipment, such as pacemakers, as well as many other
electronic devices that would be brought within a certain
proximity to the car. This issue needs to be fixed before
ECB can be used commercially.
CURRENT USES OF EBS AND ECB
Electromagnetism is not simply a way of the future for
automobiles. The concepts may be applied to any technology
with moving parts. Electromagnetic brakes in particular are
already commonly used in industries such as production and
transportation.
• Copiers and printers
• Packaging machinery
• Conveyors
• Textile machinery
• Rollercoasters
• High speed locomotives
List of devices with EBS
This list of devices represents the diversity of the utility
of mechanically applied electricity. This list is limited and
does not involve all systems currently in place.
Sustainability
A natural question posed of any aspiring technology is,
“Is it sustainable?” The heart of this question is financial in
nature – any investor would want to know if the advantages
can quantifiably outweigh the disadvantages. Would an eddy
current brake system viably afford a powerful retarding
system, while functioning in a way so that energy or other
material is not significantly depleted or wasted? The answer
lies in practical examination of the torque applicator within
the system. In ECB the torque is applied without physically
contacting the disc wheel, applying torque solely with a
magnetic field. Since there is no mechanical contact, there is
no part to be worn down over time as quickly as the
frictional system equivalent: the brake pad. The elimination
of the brake pad in ECB limits the amount of material
depleted by enabling the brakes. Also, the use of brake pads
emits thermal energy from direct contact with the brake disc.
The brake disc over time can crack from continuous braking.
This part is another major component that needs to be
replaced in traditional frictional systems that is eliminated
by the use of an eddy current brake.
The sustainable effect of switching to a system without
brake pads and discs is clearly seen: first, less material is
released as pollution and, second, there is no need to replace
any brake pads and discs during the life of the system. In
traditional friction-based brake systems, the application of
the brake pad onto the brake disc generates the mechanical
torque required to stop rotation. In the course of application,
the brake pads are worn away and the material that is worn
off must be deposited elsewhere. The dust given off of the
brake pads is given off through the wheel well and released
into the atmosphere. While the volume of material given off
as dust due to a single vehicle may seem inconsequential, the
net result of the pollution of all vehicular brake systems may
adversely affect the environment. An advantage of
eliminating the brake pads would be that the pollution due to
wear and tear of the brake pads would also be eliminated. Of
course, in a system without brake pads and discs, no brake
pads or discs would need to be replaced. Therefore in the
long-term the cost of maintenance is low compared to
friction brakes since there are no parts that require as
frequent replacement.
Finances take a significant cut when eddy current brakes
are implemented. The initial costs of ECB are more
expensive than traditional systems. Though, in the long run,
this new system pays for itself. In an estimated period of
seven years, expenses for frictional systems surpass the ECB
system. So, in the normal life span of a car, ECB would
save the owner expenses on brakes past seven years. Also,
the owner would not have to take the car in to exchange
brake pads and to inspect brake discs every year, depending
on the driver. The use of fuel can also be cut when installed
in the car. ECB can use power from either the cars battery
or another electrical power source. The application of this
system to an electric car would be able to advance green
technology already in place. Since ECB uses a magnetic
field, energy is conserved compared to frictional systems
that convert all of their energy to thermal heat. This thermal
heat is then dissipated into the air surrounding the brake, in
the frictional system. Thus, eddy current brakes do not give
off excess energy. The use of eddy current brakes in cars is
economically sound for the consumer in the long run and has
the potential to outlive the rest of the car. This braking
system does not develop new extra expenditures to be made
University of Pittsburgh
Swanson School of Engineering April 13, 2013
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