Wednesday, 27 June 2012

Red to Red, Black to Black, Blue to bits!

My Cambrian modular layout is now nearing the stage where I need the proper power supplies for testing.
(Also tied in with this entry is this thread from Model Rail Forum RMWeb.)

As a qualified person I am quite capable of building my own electrical equipment for my model railway projects. However I must state here that anyone contemplating building anything involving 230V mains equipment should be aware of the consequences of their workmanship, and if in any doubt do NOT even think about building a project like this.

The electrical requirements of my modules requires three separate and independent supplies of 16Volts 1.5Amps for the Fulgarex units, lights and l.e.d. panel lamps and two further 12V a.c .at 2 Amps for the two track controllers.

One thing that any modeller who knows about electrics will tell you is to keep any 230V stuff outside of your control panel. To this end my PSU (Power Supply Unit) is housed in its own aluminium box which connects to the layout via a multicore cable and heavy duty polarised multi pin plug & socket. The PSU then sits on the floor away from the layout and out of harms way.

Here's a couple of pictures of the PSU showing the construction.

Note from these pictures that the 230V mains wiring is first of all protected by a 2A  fuse, in the panel mount  fuse holder just above the mains cable entry.
The 230V wiring is all kept to the nearside of the case well away from the low voltage side of the PSU.
Note also that the case and the frame/screen of the transformer is well earthed.
Both transformers are salvaged ex equipment types that have been thoroughly checked and tested before being used. The Transformer on the right is the 16V supply and the one at the left has two separate 12V windings.

 The view from the other side shows the low voltage wiring.
The 16V supply is protected by a glass fuse of 2A rating and the two x 12V supplies have their own Thermal over current self resetting cut outs. (Ex H&M I think)

The flying lead and multipole plug to the layout can be seen on the right.

Take note that since these pictures were taken I have made and fitted some Plasticard fabricated shrouds to cover the exposed terminals of the transformers and on/off switch.

When I built a bigger PSU for a club layout some years ago, I also incorporated a cover interlock switch that disconnected the supply if the cover was opened. I have not done so in this case as it will only be me that opens it and I hope I don't have to for a long time!

Once again before closing I will repeat, if you have any doubt what so ever then do not attempt this sort of job, get some one who is qualified to do it for you.

Cheers for now

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