Exhibition layout power box - ideas please...?

[298]

Having seen others build something similar for a DCC command unit, I'm thinking of modifying a toolbox or similar to house the power supplies and store the cables needed for an exhibition layout. Basically something I can carry around and quickly plug into the mains and connect to the layout neatly without having a row of wall warts hanging off a 4-way on the back of the layout or trailing over the floor. A compartment inside to house a Powercab would mean everything is kept together for ease of movement, as my workbench is in the loft but the layouts are either in the dining room or garage downstairs. An external programming track/rolling road capability would be useful, as would a mains socket for a soldering iron although I cannot see how this could be achieved safely. 

 

Current power requirements are a Powercab, 2x 12v 2a DC transformers for overhead lights and powered accessories, and a 16v AC for point motors. 

 

So, any ideas or photos of of such projects, and would I need a cooling fan with four transformers in an enclosed space? 

[Andy Hayter]

You probably don't need a fan but you do need ventilation holes to allow cool air in towards the bottom and warm air out at the top.  Without ventilation the air inside the box will just heat up and all a fan does is move the hot air around.

 

My box was bought as a cheap small wooden toy/storage box and has a hardboard top screwed down.  It contains 8 transformers.  Largish holes are drilled in the base - the box itself had very shallow feet so the base sits off the ground.  The top has a nice diamond of small holes drilled.

 

For safety it is important that fingers cannot be inserted into the holes.

 

Addition holes are drilled in the side to accept the 220V input cables and the low voltage output cables.

[WIMorrison]

You already have 12v DC available therefore for the cost of a case fan I would add one - you can never make stuff too cool

[Scottish Modeller]

Hi all,

 

For the control box on Martin Stewarts - Ketton Cement(ish) I went the whoile way on cooling.

 

Toolbox used 15" Stanley with tray.

 

DCC Transformer, 6v Transformer, 12v transformer.

 

Ventilation holes in top and in one end - both fitted with fans.

 

Vent holes on side to take in cool air with fan in Pull mode

 

Vent hopes on top to exhaust warm air with fan in Push mode

 

The tray had a handle and holes already - no problem with obstruction of airways. Keep wires etc in the tray, remove when in use/#.

 

Also keep screw drivers and spare connectersin this tray.

 

That about sums it up!

 

Thanks

Phil H

[cliff park]

Of  ourse you can have mains sockets. Consider a double mains socket on the outside with a 1" back box on the inside. All the electrics are in that backbox. Even if the wooden box is opened the mains is inaccesible 

.

 

[brigo]

This subject has been discussed before,

 

 

And with respect to exhibition layouts,

 

 

Brian

[DCB]

On 19/06/2019 at 21:27, WIMorrison said:

You already have 12v DC available therefore for the cost of a case fan I would add one - you can never make stuff too cool

Heat is the issue, a couple of fans in different sides of the case would be good.

Our bandroom has 240 volt computer fans running continuously, they have run for about 8 years, so I would use 240 volt fans.

Watch the fuses. Its all too easy to end up with a 13 amp fuse on a 2 amp lead or appliance.  A nice row of proper fuse holders with the twist caps would be good.  240 volts don't half sting!

[298]

Update: I identified the need to have a NCE faceplate on the layout in order to simplify the wiring and connectivity, so squeezed one onto the front fascia. So the control side only needs two wires from the "Power Box" instead of a flat RJ lead and another pair for the track feed....

[298]

...but as an aside to the layouts requirements I've fitted another panel into this fake Jukebox, it's not quite the right era for the current layout but there is a precedent as one of the first US layouts I took interest in 25 years ago was one of Peter North's rural Rock island projects, the music from the Jukebox on the side adding atmosphere to the scene. I've kept the speaker inside and there is room for a small MP3 player too...

[Brian]

Most exhibitions will require a PAT certificate or proof such has been carried out (PAT labels on mains items etc). One of the most important requirements is that any item that houses 240 volt mains equipment can only have the insides (mains areas) accessed by the use of a "Tool".  A tool can be a screwdriver, spanner or similar that prevents simply opening the container and being able to touch the innards!    So whatever is used it MUST be fixed via possibly screws or similar that the Tool is needed to gain access.   

The next area would to be inspected would be the mains cable access place.  IMO this is best if its not an actual cable entering the housing, but I prefer to use so called "Kettle connector"  A non reversible panel mounting C14 three pin plug and mating C13 mains socket, like these examples,,, Typical C14 panel connection    Typical C13 socket and lead  

[Gavin Liddiard]

For BMRG's Mauch Chunk I suggested we use a 'Really Useful Box" as it could hold all the layout control electrics and, being made from clear plastic we could easily monitor the relevant LEDs during operation. Also they stack well, so if you use RUBs with the same footprint for stock boxes, transport to shows would be a lot safer (we didn't go that far unfortunately).

 

 

This box is their 33ltr version measuring 710mm Long x 440mm Wide x 165mm High. It stacks nicely with their 64 & 84 ltr boxes.

 

In the box is the command station, computer interface, 4x PSX circuit breakers, DCC transformer, point motor transformer, a 4 gang maind extension and a 12v DC power supply for the signals on the layout and the case cooling fan.

 

The coooling fan is extremely important as, during operation, it keeps the contents cooler than with no fan and the lid off (as was problematic at Glasgow 2019).

I have since modified the layout to provide equal cooling to the two main Lenz transformers.

 

 

The long tag strip in the middle sends all the power and control to the layout via a loom and a 36 way automotive connector.

 

The plywood base in the box to which all the components are mounted sits on 20mm blocks which allows the leads from the transformers to be loosely coiled below out of the way.

 

 

 

In use the box sits on a shelf between the legs of a baseboard. With the lid closed the 230v flex, usb for computer and layout loom exit the box via a cut-out in the lid at the back.

Edited January 7, 2020 by Gavin Liddiard

[298]

Many thanks for the replies, voltages are still contained inside original equipment, the only change being a c14  plug to fit the socket on the layout table. 

 

I've yet to tidy it up inside but eventually decided on a spare "Aluminium" case, which turned out to be made from compressed Chinese newspapers when I cut it. A single 8 core lead takes power to the layout so setting up means only one connection to the layout. I also fitted a digital voltmeter+ammeter to monitor the current draw by the layouts accessories.