REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BANGALORE-560064

Electrical and Electronics Engineering Department

EDDY CURRENT BRAKESNAME: MS. ANSHITHA S NAMBIAR

USN: 1RE11EE010

GUIDE: DR. B.P. DIVAKAR

CONTENTSIntroduction

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

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

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

REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BANGALORE-560064

Electrical and Electronics Engineering Department

CLASSIFICATION OF EDDY CURRENT BRAKES

• CIRCULAR EDDY CURRENT BRAKES

• LINEAR EDDY CURRENT BRAKES

REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BANGALORE-560064

Electrical and Electronics Engineering Department

• 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)

Continued..

The same holds for the power dissipated in the whole disc:

Pe = K ω2Iex2

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

• 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

ADVANTAGES

• 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

• 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

• 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

• 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

[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 c e e d ing 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 a g ' , 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

REFERENCE

REVA INSTITUTE OF TECHNOLOGY AND MANAGEMENT, BANGALORE-560064

Electrical and Electronics Engineering Department

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