Hello, I want to make a small train that is moved by electromagnets at the side of the train and wanted to ask which electromagnets will be best. It has to be pretty strong enough to propel it forward and can be controlled with an hbridge
You will need to experiment to find out what works with your train. Adafruit sells one or more electromagnets.
The one adafruit sells isn't strong enough to attract the train forward, and like it's for a project, but I'm not funding, I have details of train, but have to submit final list of things i need before i get materials
Have you determined the shape of the electromagnet and the physical design of what the magnet will pull/push against?
Update: Search for "solenoid engine" and look at the images. You can duplicate the two cylinders on a steam locomotive by replacing the cylinders with electromagnets.
Are your magnets attached to the train or are they attached to the ground? How far will one set of magnets allow the train to move?
The electromagnets are through the walls around the track, and there are permanent magnets on the side of the train. The magnets in front of the train just have to attract the train towards and magnet behind the train repel it away them to start the momentum, then they go off. and it's a cycle
So it's a matter of timing the various electromagnets. Are you monitoring the train movement so you can switch the magnets at the right time?
At the start of when the train is to move, how do you know which electromagnets to power and which polarity?
yh, I'll run some tests, and find out the right intervals to switch the polarity of the electromagnet.
There'll be a starting point of the train. I'll use servo motors to stop the train at the starting point. Just need to find the right electromagnets that can push and pull train
Might be of great help in doing this is to draw the magnetic fields from each magnet in your drawing and estimate the attraction/repulsion when the train is stationary. Your current drawing shows the magnets will only interact at the outer limits of the magnetic fields.
wdym?
English, please!
Paul, I think this stands for "What Do You Mean".
The problem I see here is that electromagnets will have to be mighty powerfully to do this. I don't think it is at all practical. Electromagnet fields drop of at the inverse cube of the distance, so unless they get really close up you will not see any effect.
What you are trying to do is to unwrap a DC motor, but look at a real permanent magnet motor and you will see the gap between the permanent magnet and electromagnet parts is very small indeed. It sounds like you have not got a real handle on what you are trying to do along with the sort of pulling force you get from a magnet.
I can make the walls as close to the track as possible. The first electromagnet will be really close, so as to give it a starting push. Since I'll use superconductors for the train momentum will remain for longer and reach the next set
Hi, @l4v3r
How much funding do you have available to use "superconductors"?
Is the train running on tracks, or are you suspending the train magnetically?
What level of education is this a project?
Tom.. 
So you have liquid helium for cooling those will you!
From Wikipedia:-
Superconductivity
A superconductor is generally considered high-temperature if it reaches a superconducting state above a temperature of 30 K.
Do you even understand what that means? It means you have to construct your coils with superconductors. Unless you are doing post doctoral research on this project, then let me assure you that you wont be using them.
A level EPQ, I can get up to £2000 for the project
yh I have liquid Nitrogen to cool it, y there so much doubt
It will only work for like a minute but it's still be good, and if I finish early might be able to put the whole thing in a vacuum, to increase the time.
The tracks are made of neodymium magnets to let train hover above it