eddy current break system seminar ppt

1. Presented By :~
Sumit Kumar Singh

2. Contents :~
Introduction of eddy current
Introduction of eddy current brake
Circular eddy current brake
Linear eddy current brake
How eddy current brake works?
Advantages
Disadvantages
Applications
Future Aspects
conclusion

3. Eddy currents are electric currents induced
in conductors when exposed to a changing magnetic
field; due to relative motion of the field source and
conductor or due to variations of the field with time.
This can cause a circulating flow of
electrons, or current, within
the body of the conductor.
These circulating eddies
of current have inductance and thus induce magnetic
fields.

4. Š Eddy current brakes, like conventional friction
brakes, are
responsible for slowing an object, such as
rotating machinery, a moving train, or even a
roller coaster
Š There are two basic types: (1)rotational
(2)linear

5. circular eddy current
brake system
Eddy current brake works according to Faraday's law of
electromagnetic induction.
According to this law, whenever a conductor cuts
magnetic lines of forces, an emf is induced in the
conductor, the magnitude of which is proportional to the
strength of magnetic field and the speed of the conductor.
If the conductor is a disc, there will be circulatory currents
i.e. eddy currents in the disc. According to Lenz's law, the
direction of the current is in such a way as to oppose the
cause, i.e. movement of the disc.
Essentially the eddy current brake consists of two parts, a
stationary magnetic field system and a solid rotating part,
which include a metal disc.

6. During braking, the metal disc is exposed to a magnetic
field from an electromagnet, generating eddy currents in
the disc.
The magnetic interaction between the applied field and
the eddy currents slow down the rotating disc.

7. LINEAR EDDY CURRENT
BRAKE
The principle of the linear eddy current brake has been
described by the Foucault.
The linear eddy current brake consists of a magnetic yoke
with electrical coils positioned along the rail.
This magnet does not touch the rail, as with the magnetic
brake, but is held at a constant small distance from the rail
(approximately seven 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 , and causes eddy
currents.
These disturb the magnetic field in such a way that the
magnetic force is diverted to the opposite of the direction
of the movement

9. Working Principle

10. Magnetic field lines across the
magnetic material inside a copper tube

11. Direction of magnetic lines of force due
to magnet in copper tube

14. (Arrangement of ECB between train wheels)

15. (Arrangement of ECB in high speed trains)

16. ADVANTAGES:~
Independent of wheel/rail support.
No contact, therefore no wear or tear.
No noise or smell.
Adjustable brake force.
High brake forces at high speeds
It uses electromagnetic force and.
not friction.
Can be activated at will via electrical signal
Low maintenance
Light weight

17. DISADVANTAGES:-~
Braking force diminishes as speed
diminishes with no ability to hold the load
in position at standstill.
It can not be used at low speed vehicles or
vehicle running at low speed.
ECB is used with ordinary mechanical
brakes.
Nowdays ECB is using only for safety
purpose.

18. Applications:~
It is used as a stopping mechanism in
trains.
It is also used in the smooth breaking and
functioning of roller coasters and such fast
moving machines.

19. 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.

20. CONCLUSION;~
ECB is a good invention for the speed
control of high speed vehicles
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.
It makes use of opposing tendency
of eddy current.

21. .