Model railway power supply

[FiremanT]

I am trying to redo a railway / Xmas village scene diorama. I started a few years back for my grand daughter, but although the train set was reasonably expensive it is too fragile, and now a bit rubbish, so want to dump that and use a Hornby set.

This one will run around the Xmas tree, so I don't want the model houses etc to be individually switched. I also do not want to spend a packet where I can save £££'s.
My idea is to buy some small round push button switches that can be mounted directly onto the base board. I will then run flex to the individual displays to power and switch from the front of the display. I may have to replace some of the lamps and lampholders.

If I find there are people that can help, and have an interest in modelling, I may return with more questions, but for now:
I thought if using one r two the many plug in appliance adapters that are kicking around. I intend to cut of the outlet plug and connect to a terminal strip or bus bar. From that I will wire to the switches and then to groups of the models - so pushing one switch will power several individual units. I will have to look at the amperage of these lights, and things like Ferris wheel but what are the implications if I don't get a perfect match? I seem to recall that it is okay to use an adapter that is significantly higher output than the demand , but not the reverse.?

Is there anything basically wrong with my idea?, and I would welcome any (constructive) comments

Thanks for reading

 

[RandomGrinch]

I thought if using one r two the many plug in appliance adapters that are kicking around. I intend to cut of the outlet plug and connect to a terminal strip or bus bar.

Yes, there's nothing wrong with that.
12V DC or 9V DC PSU's are common and are useful supplies.
Don't use any old unregulated supplies that you may find, the voltage can drift a lot depending on the applied load.
When you cut off the connector, check the polarity before connecting anything sensitive.
And if you can, find a power supply that has a figure of 8 lead supplying the (extra) low voltage - the round leads can often be coaxial, making connections difficult as the cores are more delicate.

Alternatively, if much of your diorama is illuminated by LEDs, you could consider supplying it from a 5V USB supply. Again, they are cheap and plentiful.
And with the use of a powerbank, your display wouldn't even need to be plugged in.

I seem to recall that it is okay to use an adapter that is significantly higher output than the demand , but not the reverse.?

Yes, an underloaded supply will last far longer than an overloaded one!

My idea is to buy some small round push button switches

Although this is where I'm confused, it's probably terminology, but small round push switches are usually push to make.
Do you mean something like a round SPST rocker or latching switch?

 

[FiremanT]

Yes, there's nothing wrong with that.
12V DC or 9V DC PSU's are common and are useful supplies.
Don't use any old unregulated supplies that you may find, the voltage can drift a lot depending on the applied load.
When you cut off the connector, check the polarity before connecting anything sensitive.
And if you can, find a power supply that has a figure of 8 lead supplying the (extra) low voltage - the round leads can often be coaxial, making connections difficult as the cores are more delicate.

Alternatively, if much of your diorama is illuminated by LEDs, you could consider supplying it from a 5V USB supply. Again, they are cheap and plentiful.
And with the use of a powerbank, your display wouldn't even need to be plugged in.


Yes, an underloaded supply will last far longer than an overloaded one!


Although this is where I'm confused, it's probably terminology, but small round push switches are usually push to make.
Do you mean something like a round SPST rocker or latching switch?

Thanks for comments, it is appreciated.

Yes, you are correct, I had been looking for PB, but realised (round) rockers are the way to go. I thought round will be easier to fit onto the base board than making small rectangular holes (avoiding using proprietary panels).

The tbulbs may or may not be LED's, I need to climb into the loft to get all the gear. I have ordered some LED's, but they are 12v, hope they are not too bright. If I applied,say, 6V, am I right in thinking they would not work at all?

I have found a 12V 2000ma plug in "switching" adaptor, but it does not actually say "regulated" on it. Can I assume that this is not suitable? Bear in mind that this is for the grand kids when they visit, so won't actually be on all the time (if that is at all relevant). I had rather hoped that I would start to save some cash, when my kids became adults!

On the useful side, I got a Amazon 20% toy voucher, which I used against the £75 train set, bringing it to the cheapest I have seen when taking P&P into account.

Thanks again

 

[ericmark]

Switching I would assume means switch mode power supply? This is a form of regulation, however seem to remember the engines use a perment magnet motor and the pulse controllers could destroy the perment magnets? Not sure about this, a resistor speed controller tends to start the train with a jerk as once it starts to move current drops and so voltage raises, so a regulated voltage is better.

I would think 9 volt regulated would give a nice speed, full speed it likely too fast. An LED has a fixed volt drop, red for example is 1.2 volt, so an LED on the common of a 7805 regulator can lift the voltage to 6.2. think white is 3 volt.

This may be better in UK electrics on this forum.

 

[RandomGrinch]

This isn't about control for the locomotive, this is a supply for the buildings in the diorama.

This may be better in UK electrics on this forum

No, definitely not!
We know how any threads on there can be sidetracked

If I applied,say, 6V, am I right in thinking they would not work at all?

The LEDs themselves, illuminate when supplied with a very low current, which also translates into a low voltage - between 1.8 and 3V (depending on colour).
12V LED strips have in-built resistors to reduce the current flow through the LED. Running them at 6V, they should still illuminate, but less brightly.

I have found a 12V 2000ma plug in "switching" adaptor, but it does not actually say "regulated" on it. Can I assume that this is not suitable?

Yes, a switching PSU is regulated and @ 12V & 2A, has a decent amount of power.

 

[RandomGrinch]

This is a form of regulation, however seem to remember the engines use a perment magnet motor and the pulse controllers could destroy the perment magnets?

As an aside, the standard for digital control of locomotives is DCC (Digital Command Control). This provides approx 18V AC formed by an asymmetric command signal.
A decoder on the locomotive, rectifies the AC to provide 12V DC for the train functions and a PWM supply to control the motor.
Even my oldest Lima loco runs ok on DCC, but it needs a decent decoder and lots of tweaking.

 

[ericmark]

I am so out of date, most the locos we use 16 guage are powered by lighter fluid, and a burner to generate steam. And it was around 1992 when I last used a toy train.

 

[FiremanT]

As an aside, the standard for digital control of locomotives is DCC (Digital Command Control). This provides approx 18V AC formed by an asymmetric command signal.
A decoder on the locomotive, rectifies the AC to provide 12V DC for the train functions and a PWM supply to control the motor.
Even my oldest Lima loco runs ok on DCC, but it needs a decent decoder and lots of tweaking.

Until I started this little task, I had never heard of DCC. As far as I can see , even the brand new set that I have ordered is not DCC and has no capability to be changed (DCC ready). Probably as it is marketed as a kids train set.

I would love it if the kids got into train set modelling, which is why I went for a “proper” make, with a view to expansion. But the DCC /non DCC may limit this. But it will do for now.

 

[FiremanT]

I am so out of date, most the locos we use 16 guage are powered by lighter fluid, and a burner to generate steam. And it was around 1992 when I last used a toy train.

I like the sound of that, but my daughter may object to me introducing the 3 yo boy to lighter fluid.

 

[FiremanT]

Switching I would assume means switch mode power supply? This is a form of regulation, however seem to remember the engines use a perment magnet motor and the pulse controllers could destroy the perment magnets? Not sure about this, a resistor speed controller tends to start the train with a jerk as once it starts to move current drops and so voltage raises, so a regulated voltage is better.

I would think 9 volt regulated would give a nice speed, full speed it likely too fast. An LED has a fixed volt drop, red for example is 1.2 volt, so an LED on the common of a 7805 regulator can lift the voltage to 6.2. think white is 3 volt.

This may be better in UK electrics on this forum.

Re the magnet. As far as I can understand (and re-remember from my childhood large set up) trains use to have a magnet to help stay on track. The problem is that it attracts ferris dust and junk which migrates into the motor , so now is not used. In fact, I read that the recommendation is to remove the magnet if running old loci’s.

I do remember that au had an early Flyibg Scotsman, and mail coaches that had auto doors that trapped parcels as it sped through the station. I just interest at about age 15, and my Father sold the lot - probably for a pittance.

 

[ericmark]

Oh, I remember the magnetic wheels, never had any, but thinking of the old DC motors, field was a perment magnet. I only had the auto coal trucks, mother hated the plastic coal in the carpet.

 

[Justin Passing]

I would have thought a low flat box would be better for mounting a load of buttons, saves messing about with your train se tbaseboard?

It wouldn't be too difficult to make all the lamp buttons dimmers. Lots of ways to do that. Some pushbutton rocker sitches have nice litle leds built in, which you can make go dim / bright the same as the model one.
It might sound overkill but you could do all the controlling with one Arduino mini/nano and a n output board. They're made with pulse-width-modulation facilities suitable for dimming LEDs. I don't know if that would be a suitable mode of loco motor control now, I though it was how they used to do it.
If you knwow nothing wgatsoever about arduino/Pi etc use, it would all be covered in one beginner-level book. PDF would be free - I have a load. Though the boards and processors keep getting smaller, the programs would be the same.

YOu could then add timers and sequencing for level crossings and raising and lowering gates...... .

 

[Harry Bloomfield]

I do remember that au had an early Flyibg Scotsman, and mail coaches that had auto doors that trapped parcels as it sped through the station. I just interest at about age 15, and my Father sold the lot - probably for a pittance.

A lifetime ago, I had a set with a mail coach, which opened a scoop as it passed the collection point hook, to collect the 'mail-bags', further along, it would fire the collected bag back out, into a collection bin.

 

[Harry Bloomfield]

I am trying to redo a railway / Xmas village scene diorama. I started a few years back for my grand daughter, but although the train set was reasonably expensive it is too fragile, and now a bit rubbish, so want to dump that and use a Hornby set.

With youngsters about - Please do make sure that what ever PSU's you buy, are sourced from reputable suppliers, so they provide adequate isolation from the mains.

 

[bernardgreen]

With youngsters about - Please do make sure that what ever PSU's you buy, are sourced from reputable suppliers, so they provide adequate isolation from the mains.

I would go further and suggest that the power supplies have a wound transformer at 50Hz to ensure there is assured isolation from the mains supply.