9V Extreme - Power Supply

[Dan-147]

Arthritis in Lego wheels .... quite amazing!

Why hasn´t Lego adressed this issue?!? Very poor design indeed - with potentially serious consequences on engines!

I believe Lego has adressed the issue. The newer train wheels that come unassembled (bearing block, two wheels and a metal axle) have plastic on plastic bearings instead of the previous metal on plastic bearings (the metal axle poked through the wheels and rubbed on the bearing block). My guess is that the newer wheels probably don't wear down as fast as the older ones. Since I don't have the chance to run my trains all that much, I don't have first-hand experience. Maybe someone in the know can give us some feedback.

Dan-147

[peterab]

When it comes to the "surgical" part - replacing electrical components in the 9V transformer - I get more doubtful (I noticed the warnings....) unless I can find somebody who is willing to help me.

The surgical part is only really necessary if you plan to run more than four engines (assuming the standard controllers will handle about 1A). I wouldn't bother with that unless you find you really need it. It should be a relatively easy job for anybody with a bit of skill with a soldering iron and the ability to find the parts needed for the upgrade.

[Haddock51]

The surgical part is only really necessary if you plan to run more than four engines (assuming the standard controllers will handle about 1A). I wouldn't bother with that unless you find you really need it. It should be a relatively easy job for anybody with a bit of skill with a soldering iron and the ability to find the parts needed for the upgrade.

One thing that hasn´t been adressed so far at all is the entire issue of fusing. If you increase the output from your transformers, you most likely will have to use stronger fuses (I don´t know the size of the fuses in the standard Lego connection wire, Peeron # 5306a). How have you solved this?

Edited February 27, 2013 by Haddock51

[peterab]

I'm not sure the connection wire has a fuse, in any case we haven't had an issue using the standard wires, but part of the idea behind multiple connections is you can safely carry more current.

I'm pretty sure we've never blown fuses in the standard 9V controllers we use (I can't remember if there is a fuse in it and I couldn't find mine immediately when I just looked).

Our custom 3A transformer is fused separately.

[Haddock51]

I'm not sure the connection wire has a fuse, in any case we haven't had an issue using the standard wires, but part of the idea behind multiple connections is you can safely carry more current.

I'm pretty sure we've never blown fuses in the standard 9V controllers we use (I can't remember if there is a fuse in it and I couldn't find mine immediately when I just looked).

Our custom 3A transformer is fused separately.

I was actually referring to the Electric Train Contacts with Wire and 2x2x2/3 Brick (correct Peeron # 5306a) which has a fuse holder. Haven´t tried to open it. Never tried to short-circuit the rails in order to find out the fuse tolerance.

Edited February 27, 2013 by Haddock51

[peterab]

I was actually referring to the Electric Train Contacts with Wire and 2x2x2/3 Brick (correct Peeron # 5306a) which has a fuse holder. Haven´t tried to open it. Never tried to short-circuit the rails in order to find out the fuse tolerance.

Ah, now I know what you mean, one of the train guys from Queensland recently opened one and asked what it was for. It's not a fuse, it's a radio interference device, the wire just winds around a metal tube inside it.

[1974]

I came accoss a post on a Dutch board in which they, in addition to replacing the wall wart, suggest to replace the diodes of the bridge rectifier with higher rated ones: http://legotreinforu...oren-t1764.html . Also, the internal LM317 regulator chip is designed for 1,5A; maybe it's possible to replace this by a LM150 (3A) or LM138 (5A)?

Just remember, it's a standard linear regulator thus the wattage displaced will be around 50% higher using the full 1,5A. i'm not sure there's enough colling for the LM317 inside the controller?

However it would be fairly trivial to replace it with an LM338K + suitable heatsink (outside the controller) and new transformer/bridge rectifier

[Haddock51]

Ah, now I know what you mean, one of the train guys from Queensland recently opened one and asked what it was for. It's not a fuse, it's a radio interference device, the wire just winds around a metal tube inside it.

So there must be a fuse in the controller. Anyone knows where and what size/strength it has?

[1974]

The LM317 is shortcircuit and thermal protected. With a pair of diodes it's also protected against (to high) reverse voltage, which could happen with two controllers in parallel (worst case is only one looses power). There's no need for a userservicable fuse inside the controller. The only place a fuse should be is on the primary side of the transformer. and this is probably a onetime thermalfuse

[Haddock51]

The LM317 is shortcircuit and thermal protected. With a pair of diodes it's also protected against (to high) reverse voltage, which could happen with two controllers in parallel (worst case is only one looses power). There's no need for a userservicable fuse inside the controller. The only place a fuse should be is on the primary side of the transformer. and this is probably a onetime thermalfuse

Has anyone tested - voluntarily or unvoluntarily - what happens if you by accident short-circuit the rails, e.g. by placing a metal tool across the rails?

[alainneke]

Has anyone tested - voluntarily or unvoluntarily - what happens if you by accident short-circuit the rails, e.g. by placing a metal tool across the rails?

No need to try it, because LEGO already did (from the instructions of set 4558):

(link to original)

[Haddock51]

No need to try it, because LEGO already did (from the instructions of set 4558):

(link to original)

I have seen this information before - and I have never purposely tried to short-circuit.

The pamflet doesn´t say anything about the possible long term consequences/damages of such a short-circuit. Anyway, I am not planning to short-circuit just to verify what´s said in this piece of information.

Again, I am not an electrician - but something tells me, there should be fuses somehow/somewhere in order to prevent longterm damages, certainly in a display with complex power supply solutions and a significant amount of power, at least relatively speaking.

[rebelego]

There is some overcurrent detection that cuts off the output. No danger to shortcircuit. This is made for children to play with. The "radio interference device" is called a ferrite.

[kieran]

The regs that are used will shut down if too much current is drawn, or it gets too hot due to too much current, so it either case it will not harm it, the image of a turning loop is exactly the same as placing a metal bar across the track, if you follow the red line from left to right on the image you will see that it become blue, this is the short circuit.

[Haddock51]

There is some overcurrent detection that cuts off the output. No danger to shortcircuit. This is made for children to play with. The "radio interference device" is called a ferrite.

If you solder the connection cables directly to the rails, do you have to consider such "radio interference devices" for each connection?

[Bamos]

Haddock51

There should be a self reseting circuit breaker or at the least a fuse in the control. But I dont know how it will react with multiple controls there may be enough of a delay to cause damage.

Soldering directly to the rails will be okay. The devices are to keep the current from the train from interfering with other signals like radio or TV.

Bill

Edited February 28, 2013 by Bamos