Sciencemadness Discussion Board - Power Supply from Model Train Control

Power Supply from Model Train Control

Abromination - 12-1-2019 at 12:07

I was planning on spending the day building a power supply from scratch when I got the idea to modify a model train controller for the same use. This obviously won't work for many types of controllers, although I have an older ones that directly supplies DC power to the nickel plated tracks powering the train. This specific model like many changes the voltage depending on what speed you set it to, so it should work for a basic power supply, although it won't be to accurate.

Has anyone else tried this?

Abromination - 12-1-2019 at 16:10

Update on this: It works like a freaking charm! I soldered some alligator clips onto the end of the DC adaptor that connects to the tracks and hooked it up to my voltage meter and labeled a mark for every two volts. I proceeded to electrolyze a solution of sodium zincate and I am impressed with the control I have over it. I would highly recommend this for someone who doesn't want to spend the money on a real one. My only complaint is that I have no control over the amparage.

[Edited on 1-13-19 by Abromination]

j_sum1 - 12-1-2019 at 17:39

Nice idea.

diddi - 12-1-2019 at 20:27

the idea is good and you could use a lot of different power supplies with a little modification here and there. a trap for young players with train controllers - new ones are often pulse width modulated so you might get unexpected results.

Abromination - 12-1-2019 at 22:39

I'm sure you could modify anything with a DC output with a control dial for one, this was just what was most convinent at the time.
One of the big conveniences with the train controler is that it can easily be found at a garage sale, I have seen at least 4.

phlogiston - 13-1-2019 at 03:42

But you do have control over the 'amperage' (more properly 'current').
The current is related to voltage by ohms law. V = I * R

Simplified, think of it like this:
When you increase the voltage output of your model train supply above the minimum needed for the reaction to occur at all, the 'extra' voltage is used to overcome the ohmic resistance of the cell electrolyte, increasing the current flowing through the cell. This will speed up the reaction rate, but also increase ohmic heating of the cell. At high currents, the amount of heating can be significant.
With a model train supply, the maximum output current is limited, so I don't think you'll heat up the cell significantly.

Alternatively, ohms law shows that you can also increase the current by decreasing R, i.e. the resistance of your cell. There are several ways you could do that: Increase the concentration of ions in your electrolyte, increase the submerged area of the electrodes, or place the electrodes closer together.

Incidentally, in your first post, you did not state what you were trying to do, so it would have been hard to advice whether a model train supply would 'work' or not.

[Edited on 13-1-2019 by phlogiston]

Sulaiman - 13-1-2019 at 06:20

A used Train Controller ... Excellent idea !

1) The unit is designed to be intrinsically 'safe' for children,
..... so should be safe enugh for most of us here.

2) Ready made enclosure
..... 'loose' modules tend to die or disappear

3) Variable voltage
..... allows any current up to the maximum capacity of the controller to be used/set
..... as above, electrode area and spacing with appropriate electrolyte conductivity determine current - at a given voltage.

4) the current capacity is sufficient for most aqueous electrolysis purposes other than bulk production for pyrotechnics etc.
..... it should be sufficient for a small chlorate cell - how much chlorate per day/week/month/year do you need ?

P.S. For 'serious' work you need to be able to measure cell voltage and current,
any multimeter is sufficient, e.g :
https://www.ebay.co.uk/itm/25E6-LCD-DT-830B-Tester-Meter-Mul...
but I use one of these :
https://www.ebay.co.uk/itm/ANENG-AN8002-Digital-Ture-RMS-600...
others may choose differently.

[Edited on 13-1-2019 by Sulaiman]

Abromination - 13-1-2019 at 12:02

Quote: Originally posted by phlogiston

But you do have control over the 'amperage' (more properly 'current').
The amperage is related to current by ohms law. V = I * R

Simplified, think of it like this:
When you increase the voltage output of your model train supply above the minimum needed for the reaction to occur at all, the 'extra' voltage is used to overcome the ohmic resistance of the cell electrolyte, increasing the current flowing through the cell. This will speed up the reaction rate, but also increase ohmic heating of the cell. At high currents, the amount of heating can be significant.
With a model train supply, the maximum output current is limited, so I don't think you'll heat up the cell significantly.

Alternatively, ohms law shows that you can also increase the current by decreasing R, i.e. the resistance of your cell. There are several ways you could do that: Increase the concentration of ions in your electrolyte, increase the submerged area of the electrodes, or place the electrodes closer together.

Incidentally, in your first post, you did not state what you were trying to do, so it would have been hard to advice whether a model train supply would 'work' or not.

[Edited on 13-1-2019 by phlogiston]

Did I not mention I have no control directly over current in my original post? It was my biggest complaint. I also mentioned that it was suitable mostly just for simple electrolysis or running some equipment. I also do have prior understanding of Ohm's law.
I figured that for anything I planned to do with it would not cause a significant amount of heating.
In terms of multimeters, I have a nice one and hook it up to supply when I need them. Unfortunately, mine is quite old and I have no way to change the batteries (they irreparably fall apart if yo do) so I may have to invest in something after all.

Doped-Al2O3-fusion - 23-1-2019 at 00:29

Quote: Originally posted by Abromination

I was planning on spending the day building a power supply from scratch when I got the idea to modify a model train controller for the same use. This obviously won't work for many types of controllers, although I have an older ones that directly supplies DC power to the nickel plated tracks powering the train. This specific model like many changes the voltage depending on what speed you set it to, so it should work for a basic power supply, although it won't be to accurate.

Has anyone else tried this?

I've done it for small electrolysis cells, but it won't supply the amps you need for powering a DC motor if you need torque.