[Richard Johnson]

QUOTE (N Gauge James @ 5 Nov 2008, 05:46) <{POST_SNAPBACK}>Hello all,

I'm coming to producing my wiring diagram for the layout and I'd like to employ some kind of cab control system.

I have a double track loop with a large yard in the centre which can be accessed from both loops...

I want to use three controllers - one for each loop and one for the yard - but want each controller to be able to power all three sections. I have read that this will need some kind of rotary switch so that each set of feeds can either be off, connected to the yard, connected to loop 1 or connected to loop 2.

My question relates to poles/throws etc - I can't seem to get my head around what type of switches I actually need to get.

Many thanks in advance for any advice anyone wants to throw (oops, bad pun) my way!

***Hello James.

Ideally a 2 pole 4 position rotary switch. this would give controller 1, 2, 3 and of course "off" for each section.

regards

Richard

 

[Richard Johnson]

QUOTE (John Webb @ 6 Nov 2008, 19:01) <{POST_SNAPBACK}>James - most readily available rotary switches have twelve contacts so you end up with:
2 pole 6 position
3 pole 4 position
4 pole 3 position
as the variations you are most likely to come across. The 3pole 4position is the one that will do what you want to do.

If your controllers are all independent of each other, ie each has its own transformer or winding on a transformer powering it, you can save a lot of wiring by using the 'Common Return' system. In this all the 'inner' rails (say) of each ring of track are linked together and connected to one output terminal of each controller also connected together. The remaining output of each controller goes to the switch for each section and a single wire runs to the outer rail (say) of that particular section. This cuts the amount of wire and connections by nearly half compared to running a pair of wires to each separate section.

Regards,
John Webb

*** Hi John

You are dead right on the switches.... now they make only one or two styles which are flexible in configuration. Actually there may be a benefit to the 3rd terminal - if James wants to add lights to show which controller is connected, he can share one terminal with a separate power supply and use that plus the third to light a LED - an old mobile phnoe charger would be ideal for that..... easily done.

Re common rail.... I don't often disagree with you on anything but do on this one! Its time has passed.

Yes, it is the traditional wiring way however only ever in the UK, where area control (separate controllers for each area of the layout) has always been common. In most other places totally separated cabs with 2 wire connection and connectable to any area of the layout for progressive cab control are normally used .

I'm aware this is stated as a DC layout but that is now... and layouts can have long life.

If you use one common rail it will give potential for problems later if the layout is ever to be converted to DCC. It also removes much of the potential flexibility for DC or DCC track detection circuitry and the like. I also don't even see it as much wiring saved if a thourough job is done.. I say that as for reliable wiring you need to run wire to quite a few places on the common side anyway, so very few metres are eventually saved!

For those reasons (even in the dim distant pre DCC past) I have always disliked common rail wiring... I see it as a compromise for only a few pennies saved and in time, only a few solder joints.

So... from my point of view, for best long term layout potential, it is much better to use a far more robust approach and stick with two wires to each section

regards

Richard

 

[Richard Johnson]

QUOTE (John Webb @ 6 Nov 2008, 23:01) <{POST_SNAPBACK}>Dear Richard,

and also need a lot more insulating fishplates....

*** I've never ever used one on my own layouts - they are very ugly things. A simple gap does fine for me.

Richard

 

[Richard Johnson]

QUOTE (N Gauge James @ 7 Nov 2008, 03:21) <{POST_SNAPBACK}>Thanks for all the posts on this...

Mike/16A - thank you for your suggestions, I shall have another look at the plan. First thoughts say that that's one hell of a tight curve though...

Richard/John - oh dear, I ordered some 2 pole 6 position switches and thought to just have some of the positions unused - have I bought the wrong thing?

***No James, they will be fine - you will simply have some spare unused contacts. my comment re using the spare pole on the one john mentioned was simply opportunistic. Sorry if that confused you.

Richard