12v 'interference-free' / 'isolated' conducting pieces

[Sokratesz]

I have two of these:

And there are several for sale on bricklink. What use are they exactly? Google doesn't help :(

- Sok.

Edited July 25, 2011 by Sokratesz

[JopieK]

I have two of these:

And there are several for sale on bricklink. What use are they exactly? Google doesn't help :(

- Sok.

It probably has a spool in order to reduce interference with other devices as much as possible.

[Sokratesz]

It probably has a spool in order to reduce interference with other devices as much as possible.

Interference from the track to other devices or the other way around? And (how) does it 'help' the train?

- Tim

[hoeij]

I have two of these:

And there are several for sale on bricklink. What use are they exactly? Google doesn't help :(

- Sok.

I think that there is a capacitor in there. They are intented to be used in a large track, to remove high-frequency fluctuations in the voltage.

Most DC motors come with a small capacitor attached to them (to remove the voltage-fluctuations produced by the DC motor). Older motors often do not (e.g. the old 4.5V technic motor has no capacitor). The 12V train motor does not contain a capacitor, that's perhaps the reason that lego made a track piece that has a capacitor.

If you don't have these pieces, I would see no reason to buy them because I haven't noticed any difference, with our without a capacitor. But whether it makes any difference or not, you might as well use them since you have them anyway.

[Sokratesz]

I'm planning to build a large track in the future (I have almost 100 meter worth of 12v track now), so would it make sense to buy a few more for that? I intend to power it with multiple leads from the same power supply, say every 10 meters or so.

- Sok.

[hoeij]

I'm planning to build a large track in the future (I have almost 100 meter worth of 12v track now), so would it make sense to buy a few more for that? I intend to power it with multiple leads from the same power supply, say every 10 meters or so.

- Sok.

I wouldn't buy more of them.

In a 20-meter loop, I apply power to 2 places on the track. That's enough so that there are no noticeable voltage drops anywhere. Even if I put the train at a very low speed, I still do not see slow-downs anywhere on the track. So one connection per 10 meter is definitely enough.

Make sure that if you connect two middle rails, then there is at least some friction to slide one into the next one. That way you know that you have a good electrical connection (if you don't have a good connection, take that middle rail out, and use a tool to give a slight squeeze to the female part of the connector, and then put it back together again).

If the track is already made, if there is a bad connection somewhere, you can quickly find it with a multimeter. Once found, a bad connection is easy to fix, and when fixed, the electrical resistance of your 12V track is lower than that of 9V track (in other words, you need to supply power to fewer places on 12V track than you would need for 9V track).

One more piece of advice: I replaced all my 12V wheels by 9V wheels. This reduces friction almost in half. This way you can pull a much longer train, without increasing the burden on the motor. If I were using 12V wheels, then my 6-car 7745 (12-track length long) would be too much of a burden for one 12V motor.

[Sokratesz]

I know about the wheel thing but I'd rather not replace them for originality's sake, but maybe a little grease here and there might help. I'd say that a slightly higher voltage (13-14v) would give the motor a nice boost in power without hurting it too much in the long term?

- Sok.

Edited July 25, 2011 by Sokratesz

[simonwillems]

... I'd say that a slightly higher voltage (13-14v) would give the motor a nice boost in power without hurting it too much in the long term?

- Sok.

I wouldn't recommend that. I once connected the 13v outlet of the 12v transformer (the outlet that normally has a small strip over it to prevent you from accidentally plugging in the cables) to the track. The train motor produced a small cough and suddenly the holes in the motor where the connectorbolts are were 2 mm. wider in diameter... Not a good idea.

[Sokratesz]

Hm, strange. I'll see if I can find a really bad one to experiment with :)

[hoeij]

I know about the wheel thing but I'd rather not replace them for originality's sake, but maybe a little grease here and there might help. I'd say that a slightly higher voltage (13-14v) would give the motor a nice boost in power without hurting it too much in the long term?

The more torque the motor has to produce, the warmer it gets. If you feel the motor to check the temperature, you'll find that after running it for a while, the temperature is mostly related to the weight of the train, the type of wheels you use, and the number of curves vs. the number of straights in the track. The voltage on the track has only a very small impact on how warm the motor ends up getting (except of course if the voltage is 0).

For a 3-car train, all of this won't matter much, but most of my trains are 5 feet long, with 1 motor in it. With 9V wheels, the motor gets noticeable less warm than it does with 12V wheels (that's true at any voltage). Having the motor get less warm, to me that's a sign that it'll last longer.

It's true of course that the motor can pull more (much more) when you increase the current. That 1 motor can pull a 10-feet long train, and probably even more, but then it'll warm up more quickly so I don't do that anymore.

I think though that 12V motors are pretty sturdy and can last a long time (I do not know how long). Even so, with trains of 5 feet or more, I think it's prudent to lessen the load on them.

[Andy Glascott]

I have several (2 or 3, can't remember exactly) of these, but they all have wires coming from them to connect directly to the power transformer. I seem to remember the instructions (long lost!) saying it was for reducing electrical interference with nearby tv's, radios etc.

Can't say I've ever noticed, they are though much easier and neater to use for supplying power than wires into other tracks.

Andy

[Sokratesz]

I don't plan to run any trains more than 3 ft or so, so one motor should do then :)

[peterab]

I wouldn't recommend that. I once connected the 13v outlet of the 12v transformer (the outlet that normally has a small strip over it to prevent you from accidentally plugging in the cables) to the track. The train motor produced a small cough and suddenly the holes in the motor where the connectorbolts are were 2 mm. wider in diameter... Not a good idea.

I'm not sure but I think the 13V connector on the 12V transformers may have been 13V AC; OK for running lights, but not good for DC motors as you found out.

13V DC should be OK for a short while, but if planning on running a heavy train for any length of time keep a close eye on it. If the motor heats up you are better to add a second motor rather than higher voltage.

[Sokratesz]

I was thinking of just that, adding a second motor. Does that come with any weird consequences?

[peterab]

I was thinking of just that, adding a second motor. Does that come with any weird consequences?

I've only got one 12V motor, so I cant say for sure, but the only problem I can see would be drawing too much current for your transformer.

Many train clubs using 9V trains either use non lego controllers or modified ones so the can run extra motors, but the stock one will normally handle at least two. I'd be surprised if the 12V one couldn't handle at least two at a time.

[Sokratesz]

I'll have to test it, but what about running 4 or 5?

The LEGO power supplies are old but it would be easy to buy or build a new one that is much more powerful.

- Sok.

[Andy Glascott]

Many train clubs using 9V trains either use non lego controllers or modified ones so the can run extra motors, but the stock one will normally handle at least two. I'd be surprised if the 12V one couldn't handle at least two at a time.

My current layout has a 12v transformer supplying power to two (granted small) loops at the same time on different levels, there's no noticable drop in speed of the trains running on them. I seem to from remember years ago that more than two trains was a bit of a struggle and that's why I bought more transformers.

Andy

[Sokratesz]

I guess I'll just have to test it. I have multiple LEGO power supplies but could switch to an offbrand one if needed.

[hoeij]

I was thinking of just that, adding a second motor. Does that come with any weird consequences?

The transformer can deliver about 1 amp, and a 12V motor uses about 0.25 amp. So two motors on one transformer is OK. Most of my trains are 5 feet long and have one motor, one of them is 12 feet long and has two motors.

I can run a 5-feet and this 12-feet train together on one transformer, so that's 3 motors on 1 transformer (I'm using a blue transformer, but I'm sure the grey one can do it too). Note though that if I start up the second train, the first one that was already running slows down significantly (in other words: the voltage on the track decreases). Conversely, if I stop one of the trains in a siding, then the other one speeds up quite a bit. I have also tried 4 motors on 1 transformer. That works too (with an additional slowdown) but since that is running at the limit (1 amp) written on the transformer, I don't do that for a long period of time.

The blue transformer behaves sort of like it has an internal resistance of 10 Ohm, meaning that for every additional 0.25 amp that the trains draw, the voltage drops by about 2.5 volt.

Also note that these things "12V" "13V" are just estimates. With no trains on the track, the blue transformer produces about 16V at the top speed setting. Each additional motor lowers that by about 2.5 volts. So with 1 motor, you get at most 13.5 V on the track, and with two motors, the max is 11V (which is still more than plenty, I basically never run my trains that fast because that long 12 feet train is a cargo train that is supposed to go slow). I haven't measured the grey transformer, but since it is not a regulated transformer, I guess that it'll behave the same.

[Sokratesz]

That's interesting, so with 4-5 motors with small loads (mostly standard LEGO trains with one or two extra cars) it should be fine?

[hoeij]

That's interesting, so with 4-5 motors with small loads (mostly standard LEGO trains with one or two extra cars) it should be fine?

As a kid, I've used the blue 12V transformer for every electrical experiment I could think of (at one time I used diodes from an old TV to make a rectifier, turning the AC outlet of the transformer into DC, then added to that (in series) the DC outlet to crank up the voltage even more, and then used that to power a lego vehicle with a motor from an old tape recorder). My transformer also has seen lots of short cuts (as a kid I liked the sparks). I have come to believe that this thing is indestructible; if it were destructable, it would have been destructed. I've also noticed that when you short the AC outlet on the blue transformer for too long, then it shuts itself off for a little while, and after that, it works again. So there appears to be protection built in.

So I think that no matter how much load you put on your transformer, it's not going to break. The voltage output does decrease with additional load. With 4-5 motors, the DC output may drop to about 6 volts so the top speed is not going to be as high.

By the way, your motors, if you run them with no load (no train, just the motor) on the track, do they run at roughly the same speed? (this is a way of checking if they're good. If all the motors are in excellent condition, then their speeds will be fairly close to each other).

[Sokratesz]

I have four or five good ones, one that I opened and repaired that now runs really fast but noisy and two that run slower and with a lot of noise.

- Sok.

[hoeij]

I have four or five good ones, one that I opened and repaired that now runs really fast but noisy and two that run slower and with a lot of noise.

- Sok.

The most likely reason that the slow ones are slow is that all their lubrication has disappeared, and so they now have a lot of friction.

To overcome all that friction, these slow motors will need to draw more amps than the fast motors. So the slow motors will run warmer (and hence, wear out more quickly) than the fast motors. If your slowest motor is much slower than the fastest motor, I would recommend that you lubricate it (open it up) before you put a lot of miles on it.

[simonwillems]

Sorry to bump an older topic, but I have recently bought one of the interference free track pieces for which this topic was created.

The piece really works! I keep my 12v layout in a small room that also contains a radio. My radio still uses an aerial to receive the signal. I keep buying more and more track to extend my layout and when I got to a certain layout size (the one from the 7777 book with the bridge) I noticed my radio signal got disrupted, especially when I ran my three trains simultaneously on the same track. After fitting the interference rail near the radio the disruption was greatly reduced. There's still a slight crackling noise, but at least I'll be able to hear the music again...

So when I get a hold of some money again I'm off buying more trains to run interference free (competing with Marktplaats bids against -Sok once more... )

[Sokratesz]

Sorry to bump an older topic, but I have recently bought one of the interference free track pieces for which this topic was created.

The piece really works! I keep my 12v layout in a small room that also contains a radio. My radio still uses an aerial to receive the signal. I keep buying more and more track to extend my layout and when I got to a certain layout size (the one from the 7777 book with the bridge) I noticed my radio signal got disrupted, especially when I ran my three trains simultaneously on the same track. After fitting the interference rail near the radio the disruption was greatly reduced. There's still a slight crackling noise, but at least I'll be able to hear the music again...

So when I get a hold of some money again I'm off buying more trains to run interference free (competing with Marktplaats bids against -Sok once more... )

Oh that's good to hear :) I have a bunch of them but not had any issues yet, although I only have a very small layout as of yet.