http://en.wikipedia.org/wiki/Railway_electrification_system
[Edited on 7/5/10 by theconrodkid]
I have to earth a vehicle that runs on rails. This vehicle does not touch the rails but floats on a fluid pad of some kind. I have thought of brushes or an earthing wheel. I just thought that electric engines must take current from rails in the reverse way. If anyone can help can you U2U me.
Where is the supply coming from? Maybe a path to earth that way?
is there any reason why you cant earth through the liquid? or how about doind it dodgem style from above?
Cant use any supply it has to be independant.
getting the Lightning current from the vehicle to the rails would have to occur in over 40 locations to form a Faraday cage....big vehicle
[Edited on 7/5/10 by Lightning]
i worked on the blunderground,during a course we were told that the 3rd rail had 400 something volts and the shoe hanging down from the train acts
like a brush,cant remember too much else as my eyes were glazing over due to a lack of tea
http://en.wikipedia.org/wiki/Railway_electrification_system
[Edited on 7/5/10 by theconrodkid]
quote:
is there any reason why you cant earth through the liquid? or how about doind it dodgem style from above?
quote:
worked on the blunderground,during a course we were told that the 3rd rail had 400 something volts and the shoe hanging down from the train acts like a brush,cant remember too much else as my eyes were glazing over due to a lack of tea
just trying to get my head round the problem and the picture i have in my head is that of a canal boat running on a mains supply. am i anywhere near the mark?
quote:
just trying to get my head round the problem and the picture i have in my head is that of a canal boat running on a mains supply. am i anywhere near the mark?
If it's lightening protection you're interested in, can't you just work on the basis that rain and lightening go together so everything will be wet and conductive.....
quote:
Originally posted by Lightning
quote:
just trying to get my head round the problem and the picture i have in my head is that of a canal boat running on a mains supply. am i anywhere near the mark?
NO !!!
I think you are pulling my leg.
One Massive truck, I mean massive, running on rails that needs earthing back through the rails. Its moved by hydaulics.
might be worth contacting london underground and asking for details or train builders themselves?
ill have a word round and see if anyone works on the trains themselves
Why do you need to earth it.
If the vehicle is isolatd from the world and self powered then the earth path is the vehicle itself connected to the frame of the generator.
If externally powered then you can supply and earth and neautral path by the same system.
Ships do not have earth connections everything is bolted or welded to the ship which is the earth. They are also 3 wire systems (without neutral)
If you really need to provide a sliding electrical connection then contact a cranesupplier like Morris and look at the slider systems they use.
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If you really need to provide a sliding electrical connection then contact a cranesupplier like Morris and look at the slider systems they use.
Is this something to do with your username ?
Remember the whole point of earthing is to provide an alternative low resistance path to earth to prevent the current going through you or a structure
you wish to protect.
if the vehicle is isolated from the ground then it is highly unlikely to take a lightning hit as the circuit is in complete. If you fit an earth then
you will promote the chances of being hit. Just like a car on rubber tyres
If you ar looking for a high energy (lightning) earthing sytem then you will need something pretty solid.
eg Underground sized.
But again I don't understand why you need to earth it ?
I can probably help you. Perhaps U2U me.
D
it will have to be earthed due to it working in the proximity zone of the live overhead cables.
This is to protect both the equipment and personel working on the unit should a flashover or cable droop occur.
The means would be via a copper wheel and brushes.
The rail is a netrual earth path for the ht.
Cheers
How far and how fast does this thing have to move? If it's a sort of train then earthing through the wheels, a sliding shoe or similar is your only way, but if it's something in a factory that only needs to move slowly and for a short distance, then a fixed, self-reeling earth cable would be practicable. Even if it is to be used on a railway line, if it only needs to be earthed while in use and then only moving up to 100m or so, a fixed cable might make sense.
quote:
Originally posted by Dave Ashurst
I can probably help you. Perhaps U2U me.
D
Could consider lightning dissipators of the sort they have on aircraft.
Or an earth spike and a very long cable reel.
Have to admit i work on the overground railway, apprenticeship as train maintenace fitter now in charge of the plant, services and systems we use in
the depot.
Trains use a positive pick up shoe (+750 volts ) and use the axles as a return path, underground use the forth rail as the return.
If your vehicle is running fluid has it already been suggested of using a overhard track trolly system like the conveyor system in factories.
or a fixed arm onthe side of the vehicle touching a low level contact over the side of the vehicle.
Yes it is for Lightning Protection. We will have no problem in the earthing in the ground as this is what we do. The vehicle will effectivly be a
faraday cage. Its the connection to the rails that I need help. Ie the shoes. The vehicle is huge and will require multiple paths to earth. This is to
provide the highest level of protection in accordance with BSEN62305.
Earthing a building BTW does not increase the risk of being hit.
I cant say what the vehicle is, but it doesnt travel far.
[Edited on 7/5/10 by Lightning]