seminar on eddy current brake

1. JYOTHI ENGINEERING COLLEGE,CHERUTHURUTHY
Department of Mechanical Engineering
February 2016
Seminar on “EDDY CURRENT BRAKES”
Guided by, Submitted by,
Mr. Nikhil N.S. Anson T. Anto
Asst. Prof. JYAMEME021
Dept. of Mechanical S8, ME-A
JECC
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2. DEPARTMENT OF MECHANICAL
ENGINEERING
VISION
• To provide quality education of international standards in Mechanical Engineering
and promote professionalism with ethical values, to work in a team and to face
global challenges.
MISSION
• To provide an education that builds a solid foundation in Mechanical Engineering.
• To prepare graduates for employment, higher education and enable a lifelong
growth in their profession.
• To develop good communication, leadership and entrepreneurship skills to enable
good knowledge transfer .
• To inculcate world class research program in Mechanical Engineering.
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3. CONTENTS
1. Introduction.
2. Working principle.
3. Types of eddy current brake.
4. Circular eddy current brake.
5. Linear eddy current brake.
6. Advantages and Disadvantages.
7. Application and future aspects.
8. Conclusion
9. Reference
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4. INTRODUCTION
• An eddy current brake, like a conventional friction brake, is responsible for
slowing an object, such as a train or a roller coaster etc.
• Unlike the friction brakes, which apply pressure on two separate objects,
eddy current brakes slow an object by creating eddy currents through
electromagnetic induction which create resistance.
• It slows an object by creating eddy currents .
• Braking action is made by varying the strength of the magnetic field.
• Braking force depends on speed of object.
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5. WORKING PRINCIPLE
Eddy current brake is based on two basic laws of electro magnetics , which are
1. Faraday’s law of electro magnetic induction :-when a conductor cuts magnetic
flux an emf is induced in the conductor, induced emf is proportional to the strength of
magnetic field & speed of conductor.
2.Lenz law :- “An induced electro motive force (emf) always gives rise to a current
whose magnetic field opposes the original change in magnet field.
• The direction of the current is in such a way as to oppose the cause, i.e. movement
of the disc.
• Thus the moving conductor will experience a drag force from the magnet that
opposes its motion, proportional to its velocity. The electrical energy of the eddy
currents is dissipated as heat due to the electrical resistance of the conductor.
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8. TYPES OF EDDY CURRENT BRAKES
• There are two basic types:
1) Circular eddy current brakes
2) Linear eddy current brakes
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9. CIRCULAR EDDY CURRENT BRAKES
• In a circular, disk or rotary eddy current brake, the conductor is a flat disk rotor that
turns between the poles of the magnet.
• Consisting of a conductive non-ferromagnetic metal disc (rotor) attached to the axle
of the vehicle's wheel, with an electromagnet located with its poles on each side of
the disk, so the magnetic field passes through the disk. .
• The movement of the disc through the magnetic field of the electromagnets creates
eddy currents in the discs.
• The electromagnet allows the braking force to be varied. When no current is passed
through the electromagnet's winding, there is no braking force. When the driver
steps on the brake pedal, current is passed through the electromagnet windings,
creating a magnetic field, The larger the current in the winding, the larger the eddy
currents and the stronger the braking force.
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10. CIRCULAR EDDY CURRENT BRAKES
• The kinetic energy of the vehicle's motion is dissipated in Joule heating by
the eddy currents passing through the disk's resistance, so like conventional
friction disk brakes, the disk becomes hot.
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Circular eddy current brake on 700 Series Shinkansen, a Japanese
bullet train.

13. LINEAR EDDY CURRENT BRAKES
• In a linear eddy current brake, the conductive piece is a straight rail or track
that the magnet moves along.
• The linear eddy current brake consists of a magnetic yoke with electrical
coils positioned along the rail, which are being magnetized alternating as
south and north magnetic poles. This magnet does not touch the rail, as with
the magnetic brake, but is held at a constant small distance from the rail
(approximately 7 mm).
• When the magnet is moved along the rail, it generates a non-stationary
magnetic field in the head of the rail, which then generates electrical tension
(Faraday's induction law), and causes eddy currents.

14. LINEAR EDDY CURRENT BRAKES
• These disturb the magnetic field in such a way that the magnetic force is
diverted to the opposite of the direction of the movement thus creating a
horizontal force component, which works against the movement of the
magnet.
• The braking energy of the vehicle is converted in eddy current losses which
lead to a warming of the rail.
• Braking force is low at low speeds and high at high speeds.
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Eddy current brakes on the Intamin roller coaster Goliath at Walibi Holland(Netherlands)

17. ADVANTAGES
1) It uses electromagnetic force and not friction.
2) No contact, therefore no wear or tear.
3) High brake forces at high speeds.
4) Long Life
5) Low maintenance
6) Operates at any rotational speed
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18. DISADVANTAGES
• Braking force diminishes as speed diminishes.
• no ability to hold the load in position at standstill.
• ECB is used with ordinary mechanical brakes.
• very tough design.
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19. APPLICATIONS
• In high speed trains.
• In roller coaster for braking and smooth functioning.
• It is also used in vehicles but still not widely used.
• For high speed passenger and goods vehicle
• Eddy current brakes are best substitutes for ordinary brakes, which are
being used nowadays in road vehicles even in trains, because of their jerk-
free operation.
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20. FUTURE ASPECT
• In future ordinary brakes will be replaced by the ECB completely.
• By the use of ECB in future we can control high speed train completely.
• By some new invention of extra mechanism we can use ECB for slow
speed vehicles also.
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21. CONCLUSION
• ECB is a good invention for the speed control of high speed vehicles
• It makes use of opposing tendency of eddy current.
• We can control the speed of high speed vehicles without wear and tear in
parts of it.
• Drawback of ordinary mechanical braking system can be overcome by
application of ECB.
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22. REFERENCES
[1] Virendra Kumar Maurya, et.al, “Eddy current braking embedded system”,
International Journal of Applied Engineering and Technology ISSN: 2277-
212X , Vol.1,January 2011.
[2] Shivanshu Shrivastava, “A Parametric Analysis of Magnetic Braking –The
Eddy Current Brakes – For High Speed and Power Automobiles and
Locomotives Using Simulink” International Journal of Advanced Research
in Electrical, Electronics and Instrumentation Engineering, Vol. 3, Issue 8,
August 2014.
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23. THANK YOU
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