Talk:Eddy current brake

Eddy current brake is not equal Electromagnetic brake

In railways, an electromagnetic brake works by pressing itself via magnetic force to the rail, thus exerting its braking by mechanical friction between the moving vehicle and the rail. This is something else than the linear eddy current brake, which works without mechanical contact and thus without wear and tear, similarly to the rotating eddy current brake described in the article as it stands today.

To do:

• eliminate the redirect from "eddy current brake" to "electromagnetic brake"
• add a section on the linear eddy current brake (I can supply the text)
• create an article on magnetic brakes as described above

--L.Willms 22:54, 28 May 2007 (UTC)

Point 2: done--L.Willms 23:02, 28 May 2007 (UTC)

Point 1 and 3: done--L.Willms 06:01, 29 May 2007 (UTC)

Copy information from Track Brake article

There is more on this subject at the Track Brake article, either this page should be deleted, or the information should be copied from there.

CairoTasogare 00:14, 21 August 2007 (UTC)

I disagree. Not all eddy current brakes are track brakes, and not all track brakes are eddy current brakes. - Crosbiesmith (talk) 17:50, 26 May 2008 (UTC)

Oppose merger

Eddy current brakes are not the same as magnetic track brakes. Magnetic track brakes work by friction, the magnetic force being used to "pull" the brake block onto the rails. On the other hand, eddy current brakes work by inducing currents in the track that create magnetic fields, and do not make contact with the rails. Although these brake systems might look similar when mounted on a train, they are not the same, and I oppose the articles being merged. Is he back? (talk) 12:10, 29 May 2008 (UTC)

hello, who can send me more information, pictures and videos about eddy current brake? please send your documents to :maysam_sum@yahoo.com thank you —Preceding unsigned comment added by 85.198.1.194 (talk) 06:30, 15 September 2008 (UTC)

Questionable Claim in the Article

The article claims, "Modern roller coasters use this type of braking, but utilize permanent magnets instead of electromagnets. These brakes require no electricity. However, their braking strength cannot be adjusted."

This may not be true. The braking strength of permanent magnet eddy current brakes can be adjusted by changing the distance between the permanent magnet and the non-ferromagnetic metal moving near it. Mimigu (talk) 21:31, 4 December 2008 (UTC)

Is this correct?

"non-ferromagnetic metal discs (rotors) are connected to a rotating coil..." Why is the coil rotating? Surely if the metal disc(s) is/are rotors (which rotate), then the coil would be stationary? No? 86.185.123.247 (talk) 02:59, 23 April 2013 (UTC)

Circular Eddy Current Brake

In this section it describes the brake-

>> non-ferromagnetic metal discs (rotors) are connected to a rotating coil, and a magnetic field between the rotor and the coil creates a resistance used to generate electricity or heat.<<

-by definition a rotor is something that rotates. So we're describing something here with a rotating non-magnetic disc, and a rotating coil. I'm not an expert, but shouldn't there be a stationary part containing magnets, and doesn't the magnet's interaction with the coil create the resistance? The next sentence does go on to describe the use of electromagnets in place of magnets, but since magnets aren't part of the original description it is a bit confusing.

Also, is the non-ferromagnetic metal disc necessary? In other words, could the coil be attached to some other non-magnetic material such as carbon fiber or Fiberglas? Again, we're relying on my high-school science class understanding of electromagnetism, but I thought the resistance was caused my the interaction of magnet and coil, and that non-ferrous metal wasn't needed.

2602:306:311C:DAA9:6069:81D7:47F8:752D (talk) 17:09, 16 September 2013 (UTC)

It doesn't make sense to me either. There has to be something stationary. Needs a rewrite. Olli Niemitalo (talk) 07:27, 17 September 2013 (UTC)

It has to be a conductive material, otherwise there would be no eddy current. But it doesn't have to be a metal which normally interacts with magnets, such as iron and some other metals. It can be a metal such as aluminium or copper which does not normally interact with a magnet in the elementary way.Lathamibird (talk) 02:11, 16 December 2016 (UTC)

Dubious assertion

" When the conductive sheet is stationary, the magnetic field through each part of it is constant, not changing with time, so no eddy currents are induced, and there is no force between the magnet and the conductor."

The statement that there is "no force between the magnet and the conductor", when there is no relative motion, is obviously not true. I can take a bar magnet and hold it with one end near a steel rail, and not move it at all, and I can feel the force attracting the rail to the magnet. It is what magnets do.... Lathamibird (talk) 02:09, 16 December 2016 (UTC)

The "conductive sheet" is not made of a ferromagnetic metal (iron or steel). Most eddy current brakes use copper or aluminum for the conductor (note the aluminum disk in the electric meter image). The force between the magnet and the sheet is due to electric currents in it induced by motion (eddy currents), not magnetization as with a magnet attracting a piece of iron or steel. A magnet exerts no force on a stationary piece of nonferrous metal such as copper or aluminum. It is only the motion of the sheet through the magnetic field that creates the eddy currents and thus the drag force. Also notice that the field of the magnet is at right angles to the direction of motion of the sheet. The attractive force between a magnet and an iron or steel sheet would be perpendicular to the motion and would not exert any braking force. --Chetvorno^TALK 07:31, 16 December 2016 (UTC)

Reference to EU Technical Specifications for Interoperability

Linear eddy current brakes - "The TSI (Technical Specifications for Interoperability) of the EU for trans-European high-speed rail recommends that all newly built high-speed lines should make the eddy current brake possible."

This requires a reference. As far as I can see currently (sorry, not an expert) the 'rolling stock — locomotives and passenger' (EU Commission Reg 1302/2014) and the 'Infrastructure' (EU Commission Reg 1299/2014) TSIs refer to Eddy Current Brakes but the requirements for their use / that they must meet are Open Points (para 4.2.4.8.3 - Loc and Pas, Para 4.2.6.2.2 - Infrastructure). They don't recommend nor prohibit eddy current brakes, nor do they take a view on whether high-speed infrastructure should be built to enable their use. 2A02:587:5416:E00:9DC9:B580:7A11:8A62 (talk) 13:34, 19 January 2017 (UTC)