This document discusses eddy current brakes. It begins with an introduction that describes how eddy current brakes provide braking through electromagnetic induction and eddy currents rather than contact friction. It then explains the working principle of how changing magnetic fields induce eddy currents that create opposing magnetic fields for braking. The document classifies eddy current brakes and discusses power dissipation through eddy currents. It outlines advantages like less maintenance and adjustability as well as disadvantages like requiring electric power. Applications are described for trains, rollercoasters, mining and more. The conclusion discusses replacing ordinary brakes with eddy current brakes and future aspects.

1. REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
EDDY CURRENT BRAKES
NAME: MS. ANSHITHA S NAMBIAR
USN: 1RE11EE010
GUIDE: DR. B.P. DIVAKAR

2. CONTENTS
Introduction
Working principle
Classification of eddy current brakes
Power dissipated by eddy currents
Advantages and Disadvantages
Applications
Conclusion
Future aspects
References
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department

3. INTRODUCTION
• Design and implementation of new system of retardation (braking) for
automobiles
• Conventional systems of braking uses development of contact friction for
retardation
• Design of the new brakes is based upon the phenomenon of electromagnetic
induction and eddy currents
• Eddy current swirling current produced in a conductor subjected to a change
in magnetic field.
• Eddy current brakes slow an object by creating eddy currents through EMI-
which create opposing field, hence braking action.
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department

4. WORKING PRINCIPLE
• Electromagnets produce magnetic field from supplied current.
• Change of magnetic flux (with time) induces eddy currents in conductor
• Eddy Currents produce another magnetic field opposing first field.
• Opposing magnetic fields create force that reduces velocity
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department

5. REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
CLASSIFICATION OF EDDY
CURRENT BRAKES
• CIRCULAR EDDY CURRENT BRAKES

6. • LINEAR EDDY CURRENT BRAKES
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department

7. • Magnetic field B is steady, the induced electric field in each point of the disc is
given by E = v × B, where v velocity of that point.
• B ∝ Iex, where Iex excitation current
• Then the following proportionality law holds:
E ∝ ωIex where ω angular speed of the disc.
• Finally, the basic law of electric current state that “the power dissipated in that
particular loop is proportional to the square of the electromotive force and to the
inverse of the electrical resistivity of the disc.”
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
POWER DISSIPATED BY EDDY CURRENT (DISC)

8. Continued..
The same holds for the power dissipated in the whole disc:
Pe = K ω2
Iex
2
ρ where the proportionality constant K depends mainly on
geometric parameters of the disc and cannot be obtained by analytical
procedures.
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department

9. • Less maintenance.
• No contact, therefore no wear or tear.
• No noise or smell.
• Adjustable brake force.
• Simple in design.
• High degree of safety.
• Works even under the toughest environmental conditions.
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
ADVANTAG
ES

10. • Usage of electric power for braking
• Less effective under very low velocities
• Braking force diminishes as speed diminishes with no ability to hold the load in
position at standstill. Breaking force ∝ velocity
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
DISADVANTAGES

11. • Stopping mechanism in trains. Ex.
Japanese Shinkansen trains
• Smooth breaking and functioning of roller
coasters and such fast moving machines.
• Mining and elevator industries.
• Found in different kinds of machines, such
as circular saws and other power
equipments.
• Rowing machines and gym machines to
apply extra resistance to the moving parts
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
APPLICATIONS

12. • The ordinary brakes use mechanical blocking. This causes skidding and wear
and tear of the vehicle.
• These drawbacks of ordinary brakes can be overcome by a simple and effective
mechanism of braking system 'The eddy current brake'.
• Abrasion-free method for braking of vehicles including trains
• High reliability and safety.
• Work even in the toughest environmental conditions.
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
CONCLUSION

13. • In future ordinary brakes can be replaced by the ECB completely
• By the use of ECB in future high speed trains can be controlled completely
• By some new invention of extra mechanism ECB can be used for slow speed
vehicles
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
FUTURE ASPECTS

14. [1.] P. J. Wang and S. J. Chiueh "Analysis of Eddy-current Brakes for High-Speed
Railway", IEEE Trans. o n Mag n. , vol. 34, no. 4, pp.1237 -1239 1998
[2.] J. Lee and Y D. Chun "The Performance of eddy current brake for the high
speed trains", IEEE, Pro ce e ding s o f CEFC'9 8 , pp.203 1998
[3.] C.R.I Emson, C.P Riley, and D.A Walsh, "Modelling Eddy Currents Induced by
Rotating Systems", Co m pum ag ', 9 7 , no. 1, pp.407 -408 97
[4.] M. Hofmann, Th. Werle, A. Binder, R. Pfeiffer, "Asynchronous Linear Machine
for Railway Systems," Conference Proceedings of the ICEM 2000, pp. 223-227,
28-30 August 2000, Espoo, Finland
[5.] www.kumbak.nl
[6.] www.lineareddycurrentbrakes.com
REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
REFERE
NCE

15. REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT,
BANGALORE-560064
Electrical and Electronics Engineering Department
THANK YOU
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