LEGO 12V Train Motors

[Neil Scotland]

All,

a further update!

Good news, I decided to really work hard at cleaning a portion of track and my motors.

I have spent the day cleaning an oval portion of track. Apart from 2 motors, a very old red one and another, they now run perfectly and there has been no need to open them up! This is brilliant news and a huge thanks goes out to all those who posted some help. I still cant see an easy way to open up the motors and so despite the obvious benefit to give them a thorough clean, im not going to do this.

I think the problem with my track lies in the points which are particularly difficult to clean.

However, having now had the opportunity to use my old 12v track, i find that my new Lego Cargo Train (PF controlled) this cant get traction and doesnt work on 12v track.

Any solutions people???

[BillytheKid]

Put an 12v motor in it .

[vgo]

The easiest way to open the 12v motor is to place it against a metal anvil or something so that the edge of the top case is on the anvil and the bottom is free to move down. Then use a screwdriver or similar to press hard (or hit it with a hammer) through the two holes where you plug in the lights on top of the motor, the metal under there can take severe punishment. After you get the motor open in one end you can start prying it open with a screwdriver. This method works if nobody has opened the motor before and not glued it back together with wrong type of glue...

You need to replace the rubbers on the PF motor's wheels to get better traction on the 12v track.

[Neil Scotland]

The easiest way to open the 12v motor is to place it against a metal anvil or something so that the edge of the top case is on the anvil and the bottom is free to move down. Then use a screwdriver or similar to press hard (or hit it with a hammer) through the two holes where you plug in the lights on top of the motor, the metal under there can take severe punishment. After you get the motor open in one end you can start prying it open with a screwdriver. This method works if nobody has opened the motor before and not glued it back together with wrong type of glue...

You need to replace the rubbers on the PF motor's wheels to get better traction on the 12v track.

Further question to the 12v gurus.

Track is cleaned, motor connections are cleaned, any ideas why some motors are a lot slower than others? Did Lego make different versions or something? One if them is pretty slow on full power.

Neil

[BillytheKid]

It's normal. If it's too slow and/or makes noise, time to get it open and clean it. But it isn't a garanty it works perfectly again.

[JopieK]

Well no two motors are totally equal. Some ran more hours than others, their gear are not totally equal, etc. etc. That is why servo's etc. are more reliable. They have an internal feedback system so they run almost always exactly the same (but most servo's aren't able to revolute infinately but just turn some degrees (e.g. 180 degrees).

[hoeij]

Further question to the 12v gurus.

Track is cleaned, motor connections are cleaned, any ideas why some motors are a lot slower than others? Did Lego make different versions or something? One if them is pretty slow on full power.

Neil

When properly lubricated, their speeds are quite close to each other. Here's how you can see this: run two motors, same voltage, same amount of time. The slow one will be warmer than the faster one (check that!).

The slow one is only slow because it has a lot more friction. To overcome this friction, the motor has to work a lot harder than the fast motor, so the slow motor draws more current, and hence it gets warmer than the fast motor (if you don't lubricate it, then it will also wear out sooner than the fast motor). If the slow motor is lubricated, it'll run about same speed (at most 10% slower or faster) as the fast motor.

I've opened up 4 or 5 motors (the slowest ones that I have), and they all run as fast (within a few %) as the fastest motor that I have.

Edited January 6, 2011 by hoeij

[BillytheKid]

Well I have a few, they won't run faster after lubricated. How you explain that?

[hoeij]

Well I have a few, they won't run faster after lubricated. How you explain that?

After running a fast and a slow motor, for the same amount of time, and the same voltage, is the slow motor warmer than the fast one?

[Brickaroo]

Very happy that you didn't give up on the 12v system like you suggested you might early on. I hope you're reaping the rewards now!

12V = best ever, don't think it can be beaten unless TLG change their view of the world.

[BillytheKid]

After running a fast and a slow motor, for the same amount of time, and the same voltage, is the slow motor warmer than the fast one?

Yes, no matter how good it's lubricated.

At the long end, 12v will loose......... It won't be without a fight .

[vgo]

I have some motors that have been opened, then cleaned and lubricated. I've used two 7735 locomotives to run tests and some motors do run faster, after running 5-10 min on the same small loop the faster one which started just in front of the other is right behind the slower one. This makes running two trains on the same loop quite challenging, I need to test various trains (different combinations of locomotives and cars) to find two that run about the same speed.

[hoeij]

I have some motors that have been opened, then cleaned and lubricated. I've used two 7735 locomotives to run tests and some motors do run faster, after running 5-10 min on the same small loop the faster one which started just in front of the other is right behind the slower one. This makes running two trains on the same loop quite challenging, I need to test various trains (different combinations of locomotives and cars) to find two that run about the same speed.

If it takes 5-10 minutes for the faster one to catch up with the slower one, then you can run two trains on the same loop. Just build a siding with an interrupter rail where you can temporarily part the slower one to allow the faster one to pass.

Interrupter rails are expensive on bricklink, but it's easy to make them yourself (you'll need two of them for every siding where you want to park a train). Bend the metal clips at the bottom until they are completely straight. Then (and only then) can you lift off the metal part (you only need to do that on one side). Then make a small cut in the metal, and put it back. I put a little bit of tape on top of the cut so that the train runs smoothly over it.

At our local train show last year, I had 6 trains on a large 12V loop, typically 4 were parked and 2 were running (unfortunately, the only video footage that I have was when I was eating lunch, and only 1 train was running at that time).

[harnbak]

Those are excellent pictures, especially the first picture. You can see lots of things

in that picture...

...If you decide to open up a motor, I would start with the one that runs the worst.

That way, you lose the least if something goes wrong.

Thank you really very much for this thorough explanation - you made my day!

[Sokratesz]

Then let a track with 2x 12vmotor connected with a wire to eachother (like train 7740 of 7755) run a few laps on the track. Then single 12v motors won't have difficulty to run smoothly

I am intrigued, how does this work?

Edited June 11, 2011 by Sokratesz

[horizon]

Hi,

from this : http://www.eurobricks.com/forum/index.php?showtopic=49321

Harbak directed me here because of this:

Heya,

sorry for the old death thread arise, but better then a new topic, right?

Last weekend my 4yr old son wanted to see my old Lego train in action. The old 7740.

While some rail connections snapped due the years ( :( ), all other things seemed fine.

Started it up, build a quick model. The thing ran dozens of laps, gaining speed etc.

But suddenly.... stop. Nothing. Thing stopped running.

I only connected the main wire, so no extras for lights, stops, changes etc.

Now the engines makes a humming sound on the track but doesn't move. So it does get power, but it also drops down, then picks up again but never moves.

I cleaned a few tracks (alcohol) to make it shiny but this didn't help. However, the connectors on the engine are very brown-ish/ not shiny (so to say).

Could this be the issue?

Or could the trafo be melted?

I did the light test with one brick, it didn't come on. Did not have time to test another light brick.

When I attached the engine directly to the trafo it made the buzzing sound inside but no running of wheels. When I turned the wheels slightly the buzzing stopped. Wiggling the connectors also made sound changes.

Guess it is time to open it up.

Oh yeah, on the trafo there is the 0-12v exit and the 12v exit (closed), what's the deal with that?

[Beej]

I did the light test with one brick, it didn't come on. Did not have time to test another light brick.

So the light didn't come on? It's starting to sound like it's your transformer that is faulty. Don't go opening up your motor for no reason! Have you got a 9V battery you can connect to the contacts on the motor? That will tell you for certain if it is still working.

Oh yeah, on the trafo there is the 0-12v exit and the 12v exit (closed), what's the deal with that?

The blocked off port is wired directly to the output of the transformer inside, so outputs about 14V AC. If you have a multimeter this might be a good way to test your transformer out.

Don't bother trying to fix the transformer if it is broken, they constantly show up on ebay and wouldn't set you back more than $10US / 10 Euro.

[horizon]

Hey,

thanks. 10 dollar? That's a nice prize.

I'll try another light brick next, then some different wires to make sure.

Then I will test the trafo & engine with a multimeter.

I'll keep you posted.

Because it was cool to see the thing running again after all those years. Need to build a cool train on top as well.

[Brickaroo]

Just out of curiosity horizon, have you hooked the power connection on the transformer to the 12V plugs or the 13V plugs?

The plugs on the left in that image are the 12V plugs, the plugs on the right (they're sealed with a plastic part in the photo) are the 13V.

If you've connected to the 13V you might have some problems, can fry the motor.

Edited December 14, 2011 by Brickaroo

[horizon]

No worries, I connected on the left (0-12v).

[bricks n bolts]

If the light is not working but you are getting a buzzing sound from the motor it could be because you have shorted the track some how.

Check the connections and go around the track to see if anything could be causing a short.

[Neil Scotland]

Thanks for this. Its brilliant and i have successfully opened a red motorwhich i just felt wasnt working very well. 2 quick questions though.

1. You mention the carbon and the importance of having plenty left. Is this a small block piece on the section marked 3 and 4? If so, should this be cleaned and how do you tell if you have plenty or not?

2. Regarding general cleaning, when i opened up this motor it was quite oil(y) inside. Should i clean all this up?

3. Finally on lubrication, which bits should you lubricate and with what? I dont want to damage anything but I would like to get rid of the noisey nature of this motor?

Thanks for all your help.

Neil

[hoeij]

Thanks for this. Its brilliant and i have successfully opened a red motorwhich i just felt wasnt working very well. 2 quick questions though.

1. You mention the carbon and the importance of having plenty left. Is this a small block piece on the section marked 3 and 4? If so, should this be cleaned and how do you tell if you have plenty or not?

2. Regarding general cleaning, when i opened up this motor it was quite oil(y) inside. Should i clean all this up?

3. Finally on lubrication, which bits should you lubricate and with what? I dont want to damage anything but I would like to get rid of the noisey nature of this motor?

Thanks for all your help.

Neil

About 1, I wouldn't worry about the carbon, because if it were worn, then I wouldn't know what you could do to fix it. As far as I understand DC motors, if the carbon is gone, then the motor is game over, however, in the 12V motors that I've opened, they all still had some left (it's a bit hard to see, because the color is almost the same).

About 2. It should have oil/lubricant inside of it. If it has no oil/lubricant in it at all, then it can not run well.

About 3. This noise might be coming from the parts marked 3 and 4. I had that with one of the motors. If I remember correctly, the noise went away with some WD-40 but then it came back again.

[Neil Scotland]

About 1, I wouldn't worry about the carbon, because if it were worn, then I wouldn't know what you could do to fix it. As far as I understand DC motors, if the carbon is gone, then the motor is game over, however, in the 12V motors that I've opened, they all still had some left (it's a bit hard to see, because the color is almost the same).

About 2. It should have oil/lubricant inside of it. If it has no oil/lubricant in it at all, then it can not run well.

About 3. This noise might be coming from the parts marked 3 and 4. I had that with one of the motors. If I remember correctly, the noise went away with some WD-40 but then it came back again.

Regarding the oil, do you just oil the main part of the engine. Do you think you could damage it?

[hoeij]

Regarding the oil, do you just oil the main part of the engine. Do you think you could damage it?

I do not think you can damage it. I've lubricated about 4-5 motors by opening them, but recently I actually lubricated one 12V motor without opening it.

To lubricate it without opening it, I squirted a bunch of WD-40 into that motor (there are a couple of openings, e.g. for the middle wheels), and then carefully shook the motor for a while, in various directions, to make sure it gets everywhere (without opening it, that's really the only way I can get it to reach the spots that I want to reach).

It's quite easy to tell if all the spots that I want to reach have been reached: A good motor should move with as little as 2 volts (of course, the speed at 2 volts is very low). Before I lubricated this motor, it would not turn even at 4 volts, to get it to turn its wheels it needed at least 5 volts. After I lubricated it, it now moves at 2 volts (and it runs more quietly), even at 1.5 volts the wheels already start to turn. That means that everything that needs lubrication has received some.

Of course, I don't want WD-40 to end up on the track, so I placed this motor at various angles (with a paper towel underneath) for hours to let as much as possible WD-40 drip out of the motor (you actually only need a microscopic amount of lubricant on the gears). Then I'd apply some electricity to spin the wheels, turn it again, and repeat the process to get more WD-40 out of there. Only once I was sure it was not dripping WD-40 anymore do I put it back on the track.

The lower the voltage at which the motor starts to move, the less current the motor will be using. Less current means it will get less warm, and that means it will last longer. I'm sure that my lubrication process is definitely not recommended by the manufacturer, but then again, they probably also did not imagine these motors to be still in use after 30 years (motors that were stored properly might very well still be properly lubricated, but not all motors are. About half of the 12V motors I bought needed lubrication).