DPST Switch Recs?

I think you would only need a spst, and some good ones are found in the auto department. The brand I use is a Calterm LED light rocker switch. They are rated 12VDC at 30 Amps. The LED only conducts the positive half cycle of the say 18 VAC track voltage so that the average DC the LED sees is only about 8 VDC. To save the LED from suffering the reverse voltage of the 18 VAC, connect the "Earth" terminal of the LED on the switch thru a small diode to common. Point the symbol of the diode toward common.

Chuck - thanks for the recommendation. With respect, I'm not an electrical guy. Can you please translate what I would need to do with this toggle into English?  Thanks!!!

Also - as I'm not an electrical guy, I am curious about whether I need a SPST or DPST. Here is what I am doing:  I want to be able to power down my yard that connects to my inner main line via the toggle.  I am running DCS so want to stay as close as possible to star pattern wiring with one power drop per track block.  I have an MTH terminal block for each main line, with star pattern wiring from each terminal block out to the track blocks for the given main line. The DPST has four prongs on the back so I assumed I would be running one set of wires (hot and return) from the MTH terminal block to the toggle and then solder the 5 yard power drops to the other two prongs (or use thone two prongs to run one set of wires out to a buss bar and then wire the 5 yard drops to that buss bar).  With a SPST toggle, not sure how I would accomplish this, given it has only one set of prongs and DCS requires equal length wire runs to each track block.   Thanks for any advice.  

The equal length runs to each track block is baloney, you don't need that.

Just switch the center rail power and use a SPST switch.

 

You can still run the ground/outside rail wire past the switch to keep your wires the same length should you so desire, for whatever reason, just don't cut it.

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Guys, thanks for the replies. So, I shoudnt be using a DPST?  Hate to ask but don't want to short out my house - can anyone offer a simple diagram of what to do using the SPST?      Given there's only two posts on the rear, but will have a hot and return coming to toggle from terminal block and then hot and common running from the toggle out to the yard, not sure I understand how I would wire from power and then out to the track blocks. thanks. 

Don't switch the common. It's not necessary or even recommended. So it's hot on the source to the switch, and hot on the load to the switch.

Are you saying to do what I've sketched out in the attached representative drawing?

Looks good.  If you want to switch each block, you'll have to move the switches past the buss-bar.

Here's the part about the LED in the switch...no resistor is needed outside the switch, just the diode.

       
       


The track blocks coming off the buss bar would all be yard tracks so I am hoping to use the toggle to either turn all these track blocks that are wired to the buss bar either "on" or "off" - will the setup in my sketch achieve this goal?   Thanks

If you want them all switched together, the single switch works fine.  Some folks want individual control of yard tracks.

       
       


Cjack - sorry I'm not an electrical guy - are you saying that the way to make the light on the toggle work is to install an external "diode?"  Separately, the back of the toggle to my knowledge has two prongs but your drawing looks like three prongs are needed? Again, apologies for my ignorance on this subject and really appreciate the help.  Peter

Cjacks drawing is for the lighted toggle switch mentioned earlier...those have 3 terminals.  Diodes have (usually) a black body with a silver band at one end.  The silver band end matches the straight line of the diode in the drawing.

 

B

I called four places looking for this diode. Can't find anywhere. I need 2. Any thoughts on where I might find this thing?  Thanks.

You must not be looking in the right place.  You can use a 1N4003 through 1N4007 for that diode, they're available everywhere.

 

Here's the 1N4003 diode at Digikey, you can have ten of them for $1.67.  Their shipping on this First Class will only be a couple of dollars, and they ship the day they receive the order.  I'd just get a few, they're very handy to have around.  I buy them in lots of 100.

You can use a 1N4001 instead....Radio Shack, Digi-Key, Newark, Allied....just 4 sources I know of off hand...there are others.

 

Difference between the 1N4003 and 1N4001 is the reverse voltage peak - both voltages are above the voltage applied to layouts (50v for the 1N4001, 200v for the 1N4003)

 

B

You can use the 1N4001, but I've lost several on train projects, probably do to voltage spikes.  That being the case, I go for the higher voltage ratings, there is no difference in cost.

 

GRJ - I don't have the first idea of this subject. I found the 4003 diode at RadioShack and am going there after work. Could you tell me which higher voltage one (or the specs) that you recommend so I can buy that one instead please? Thanks!

1N4003

Thanks. I got 4 at radio shack. I checked local electrical supply houses by work and all said that these things were on back order.  I will probably be back asking for a photo on what this entire set-up looks like installed (rocker toggle, diode and wiring to/from) - so would really appreciate someone posting this. But not gonna mess with this tonight.  It's (already) been "one of those weeks" at work so gonna kick back and take it easy.  thanks again for all the help.  

Take a photo of each of your pieces and we might be able to make a composite picture (or at least a connect wire A to wire B) drawing using the actual parts....It'll be up to you to install/mount the objects into your system.

The 1N4003 is fine, I just kinda' stay away from the 1N4001 due to the 50V inverse voltage rating.  Anything from the 1N4003 to the 1N4006 has worked well for me, I use them interchangeably on train projects.

Ok, I've now got the buss bar, the toggle and diode recommended above. Now I just need to know how to hook up the diode - to what items and how. Here is another (not to scale) rough sketch of my set-up and a photo of the toggle, diode and buss bar.  I am using DCS with star pattern wiring and the yard will have a few electrically isolated track blocks, hence, the reason I have the buss bar that wires to the yard.  Some basic "Barney style" advice on how to hook up diode would be GREATLY appreciated. I struck out trying to find a tutorial on the 'Tube.    Thank you.  Peter

Anyone?  Just need a simple sketch of the toggle and diode showing how the red and common wires from terminal block are connected to the toggle and/or the diode and then how the wires head out from toggle and/or diode to the buss bar. And in laymen's terms please as I am far from an electrical guy.   Thanks very much for the help.

Your sketch is almost there...look back a few posts to the sketch that has the 3 post toggle switch and insert that into your sketch.

I know nothing about how the terminals are labeled on the DPST you have, so you'll have to look and maybe post the labels if you cannot decypher the labels.

B

 Label the right side of the switch shown in your sketch "Supply" and the left side of your switch "Load". Then connect the diode with it's NON stripe end from a third terminal on the switch labeled "Earth". And connect the end of the diode with the stripe to the outside rail terminal on your buss bar.

Not sure where the disconnect is - the photo above shows the exact SPST toggle (the one recommended by cjack) and diode (recommended by GRJ) I have and plan to use. My question is - how to connect them to the existing wiring shown in the rough sketch I provided in that same post?  Here is the rough sketch - now updated to show these items that were pictured in the photo. They are unconnected to anything in my sketch because that is the crux of my question - how to connect / wire them (in laymens terms please). Thanks.

Exactly like this?  Thanks.

Perfect

Chuck - thanks very much for confirming.  Phew!

Sorry - but I think my sketch is wrong in comparison to the one you posted. Chuck, your initial sketch shows (top to bottom prong) earth, load, supply. The drawing on the back of the toggle (see photo) top to bottom again says earth, LED, load. My last drawing that you said was correct May have the wires mixed up as it has (top to bottom) load, earth, supply.  Just want to confirm the right order?  Thanks!

That's right, the switch in your drawing is out of order, but I wasn't thinking. Your diagram is correct in terms of the labels you gave the wires. The sketch is labeled "supply", "solder", and "load".  And the switch is labeled on it's back "supply", "load", and "earth". Solder the diode to the "earth" pin. The "supply" wire to the "supply" pin and the "load wire to the "load" pin. I guess you should redraw the switch interchanging the "load" and "earth" pins so there's no mistake.

Ok will do as soon as I get home. At a Boy Scout event now with my sons. Prolly post around 7:30 or so. Thanks for all the advice.

Chuck,

Ok, I've done another sketch. I set it up per your original drawing (I think). And I also purposely put the wording that actually appears on the toggle on the toggle in my sketch for two reasons: (1) it looks to me like it is exactly opposite of the tags in your first sketch and (2) the toggle says "LED" in relation to the second prong, which I believe also differs from your sketch.  Now I may have completely confused things so I listed all this to ensure clarity so I don't misinterpret your much appreciated advice.  Thanks again!

Front and back photos of actual toggle (both photos have same orientation - the red LED light is on top of rocker).

Ok, that's good. That will work.

Hey Chuck and GRJ - just wanted to let you know that I finally got the chance to solder everything together and jerry rig the electrical connections (before permanent installation) and ------ it works!  The multimeter show a 0.5 power degrade (17.5v rather than a full 18v or a little more everywhere else coming from my Lionel 180 PH brick) but I suppose that should suffice for a yard.  Thanks so much for helping me through this.     As a follow-up, I plan to put plastic rail joiners on all three rails at the break between main line and yard to ensure yard is truly electrically isolated. Nothing wrong with this, right?  Peter