Question About My Lighting Project

[jonathan]

As usual my search for knowledge revolves around things electrical.

So... my question is:  How does one wire a rotary switch?

Now the back story:

I've been wanting to start a signal system on my layout ever since I started building.  Expense and lack of expertise has kept me from attempting it.

Well a few things have come together since then.  A trip to the B&O RR Museum gained a couple of free signal bridges (B'mann Plasticvilles BTW).  Here's a photo below.  I painted them and added some aluminum tubes to hide all the wiring:









Next, I found an old power pack at an LHS--just happens to be an old Bachmann pack. Got it for a couple of bucks.  I also ran some 16 gage wire around the layout as a bus feed for the signals and whatever else needs some juice:



That'll be hidden by the fascia or skirting I will put in "someday".

The big expense was a pair of CPLs (B&O Signal Heads), complete with resistors:





Now the confusion over the 6 position rotary switch, which I picked up at Radio Shack for around $3:





I assume the two poles in the middle are connections for the power source, and the outside ring of poles are for the bulb (LED) leads.  So, my guess is I can run the signal's common lead (black) to the bus wire (-).  Then I can run a common lead from the center pole of the rotary switch to the other bus feed (+).  Then the LED leads can be run to the outside poles of the rotary switch.  These are guesses.  This is the part I need help with.

Part of the confusion:  Why are there twice as many poles as positions for the switch?   Am I required to run a wire from the outside ring to the inner poles?  Actually, I probably have more questions than I can list right now.  So perhaps a kind someone can start me down a simple path so I can understand how to wire the switch.

Thanks once again.

Regards,

Jonathan

Addendum:  My plan is to wire some sort of terminal to each switch position so I can connect other signals.  Eventually, I would like to control all the signal aspects on my two track mainline with the six positions of the rotary switch. jev

[richg]

Hi Jonathan

The switch is a two pole, six position switch. Use the resistance option on your multimeter to see which terminals are for which position. Rotary switches are hardly ever labeled. I have been using rotary switches since the 1950's with my first shortwave radio kit.
Put up a drawing of the wire's,  led's and resistors.

Rich

[jonathan]

Thanks, Rich.

OK, I've found a diagram of the switch in question:



My theory is I can connect positions 7-12 to act as my common lead.  Then I can us positions 1-6 to connect my various lighting conditions.  A simple expample would be  connecting all red LED leads to #1, all green leads to #2,... etc.  That is grossly oversimplified.  But I'm after confirmation of the concept.

Studying the switch and diagram leads me to this conclusion.  Studying the problem on line has not helped.  All the examples refer to electric guitars.  I cannot find a simple description of the switch's set up.

The center two poles make no sense to me (A/C?+/-?).  Perhaps I needn't worry about them?  Again, are the center poles the common lead?

Regards,

Jonathan

[richg]

You have two isolated six position switches on a common shaft. The two contacts near the center are the common for each six pole side. You can see this with your multimeter. I hope you have a multimeter. It makes trouble shooting and analyzing things much easier. The switch is not a 12 position switch.
Do a Google search for two pole six position switch.

I have posted the below meter a few times here in case you did not see it. I have three and they do everything I need with different electrical/electronic projects.

http://www.harborfreight.com/catalogsearch/result?q=multimeter
Get the cheapest one and the big set of clip leads. You have not mentioned if you have a meter. You will need one or two if you want to work at what I call the component level. I have been using these meters for some years and they work very well and cheap to replace if you damage one.
I know I am over bearing when mentioning using a multimeter..

I am also wondering what the resistor values are? There are online resistor color code calculators.

http://www.csgnetwork.com/resistcolcalc.html

Rich

[Jim Banner]

The common connections for the two poles are the two connections near the center of the switch.  One connects to any one of six contacts (say #1 to #6 in your diagram.)  The other common contact connects to any one of the other six contacts (say #7 to #12 in your diagram.)  All you really need is a single pole six position or throw switch so really you have two switches in one.  Each one is a SP6T (single pole six throw) switch,  Together they make a DP6T (double pole six throw) switch.  As you have figured out, the common terminal connects to each throw terminal depending on the position of the switch.

As far a wiring is concerned, the common switch terminal connects to the power pack + output.  The first three throw terminals (1, 2 and 3 in your diagram) connect to the three coloured wires of your signal head.  And the black return wire from your signal head connects to the power pack - output.

I know you understand the next concept but let me include it for others that may read this thread:  You do not have to connect the switch's common terminal directly to the power pack just as you do not have to connect the signal head return wire directly to it.  If you are using more than one signal, you are far better off to run a power bus from the power pack terminals to all the places you expect to have your rotary switches.  Then tap the + and - off the bus wires at convenient points.  The bus wires could be 16 or 18 gauge.  Red for +, black for - would be good colour choices.  In the same situation I would probably use 14 gauge Romex type house wire by stripping off the outside jacket, using the black wire as the black bus wire, the white wire coloured red with a permanent marker as the red bus wire, and the bare wire I would save for future projects.

Jim

[Doneldon]

jonathan-

You don't need to connect your common to the rotary switch at all. Just connect all of your signal lights to the common and switch just the one side. That will take less wire. Also, you can switch more than one light with each position of your switch. For example, one position could turn one signal green and the one behind it red. That's not a big deal with only two signals but it can be handy to do if you have several. Then one green signal could also go to a red one behind it, a yellow before that and even a green before that. But I predict that you'll get tired of switching all of the signals sooner or later. You can still use these signals but control them with track detectors and relays. You can even leave your rotaries in place as long as you disconnect them from the power source. That will allow to manually switch signals if you want, or test the signals.
                                                                                                                                      -- D

[jonathan]

Gentlemen:

How can you beat three teachers for one student?  The picture is becoming clear now.

I do have a multimeter. However after the descriptions provided, I found it unnecessary when testing out the switch.

With the signal head's common wire (black) to bus wire A, the rotary switch common pole to bus wire B, and the yellow LED lead to position 1, we get this result:


Now the green LED lead to position 2:


I know it's not magic, but sometimes... wow.  This opens up a world of possibilities.  I began to understand when Jim wrote to the affect that the rotary switch really has 12 positions:  1-6 have a common in the center, and 7-12 have a common on the other center pole (DP6T).  The mind reels with the possibilities.  Through clever use of polarity, one could use half the rotary switch to control the mainline lighting, and use the other half for yard/junction lighting.  Since my home layout is relatively small, the one switch should be all I need.  Block detectors are very cool, but probably not necessary for my round and round configuration.

Now I need to figure out where and how to mount the switch.  Also, some sort of terminals will be needed for adding additional signals to the switch poles.  Anyway,  I will report back when I've made some progress on setting up the first signal bridge.

Thanks-a-million, Rich, Jim and Doneldon!

Regards,

Jonathan

[richg]

Hi Jonathan

Nice to see a plan come together.
Mounting the switch is easy, for various values of easy. I use a Unibit to drill the hole. I think it is 3/8 inch hole. The tab on the front is to put in a small hole to prevent turning the whole switch but I have never found it necessary if the lock washer and nut are used properly. I just bend the tab out of the way.

http://www.irwin.com/tools/browse/drill-bits/unibit-step-drills

Drill slowly. It is easy to go to the next hole diameter with the bit. I have used these bits for some years. Many times replaces a drill index.

When wiring the switch, remember you are looking at the back of the switch or you will find the switch positions incorrect. Don't ask me how I know that.

Rich

[jward]

that was a good idea to route the tubing for the signal wires up one of the legs of the signal bridge. did you have any trouble stuffing all that wire down the tube?

when i did signals, i used brass tube instead of aluminum, and was able to solder the common wire to the tube. that way i only had 3 wires to fit in the tube. naturally, with signals, the smaller size wire you use the better.

whose colour position lights are you using?

[richg]

Quite a few years ago I made some single target lights using bipolar red/green two lead LED's and used a 3/32 inch brass tube for the pipe. The tube was common.
For a plastic signal bridge, I use #30 Kynar wire. Magnet  wire, #44 is very small and works just fine.
LED's require about 10ma each for normal operation.

Rich

[jonathan]

Actually, I tested with extra fine wires this morning and was able to stuff all four leads up one tube (not easy, but doable).  I have a tube down the back of each leg.  The signal bridge in the middle of my layout will need 4 CPLs (2 per side).  I'm starting with a bridge that will be mounted in the back corner, so only one side needs CPLs.

I will be moving the resistors to under the layout.  This is a go slowly project, as wires are tiny and the bridges are plastic.

Thanks for the tips on mounting the switch.  My control stations work pretty well, but they aren't attractive--another part of the hobby to tackle one day.

Regards,

Jonathan

[richg]

Hi Jonathan

Having pulled wires for many years in electrical machine installation, I use one wire to pull the others. For some of my installs, I solder a single wire to the wires going into a tube, slip the one wire up the tube and then pull the whole bunch up through the tube.

I use a hollow nut driver to tighten the nut that locks the control in place. Some nut drivers have a solid shaft and no room for the control shaft. It is easy to mar the panel using a plier or adjustable wrench.
Make sure to use the flat washer under the nut that comes with the switch to prevent marring the panel. A complete switch has a lock washer, flat washer and nut.

Rich

[jonathan]

Just a little update:

The great advice so far is paying off.  Stringing wires, while not fun, is not so bad once you get the hang of it.






I'm only using three selections on the rotoary switch for this project, but I soldered, and labeled leads to all the poles.  I know I'll use 'em eventually:



Question:  Is there a cheap way to make a distribution block?  Haven't found one at Radio Shack.  Perhaps they call it something else.  The MRR version is a bit pricey, especially since I will need several to connect so many signals eventually.

I'll post a final note when everything is up and running.

Thanks again.

Regards,

Jonathan

[richg]

http://www.allelectronics.com/make-a-store/category/755/Terminal-Strips/1.html

I buy from this company.

I have sometimes made my own with a narrow strip of wood and some sheet metal or wood screws. I just use my imagination. This is low voltage.

Rich

[jonathan]

That looks much more reasonable.  Thanks, Rich.  The jumpers are what connects the terminals together?  Can I use my own wire?

Regards,

Jonathan