Hi guys,
So the layout is going well, except I seem to have something wrong with my staging track power switches. The idea was to be able to cut power to some staging tracks so I can have multiple engines parked on the layout but not all powered up and running at once. I bought small lighted SPST switches (12V/6A) for the facia panel to cut power to various sections of track.
When I wired the layout I basically cut a small gap in the POS rail for these sections and ran the switch in the middle of the feeder wire between the buss and these sections of track. The NEG rail is continuous and powered thoughout the layout. I figured if you cut power to one rail that would basically cut power to that section of track. Isn't that the idea behind a SPST switch? I must have something wrong here.
Last night, before I cut the feeder wires and added the switches I did a test run with a sound loco and every section of track worked fine. Today I cut the wires and installed a few of the switches. With no locos on the layout I did see immediatley that the lighted part of the switches doesn't work. But I realized there is only one polarity (POS) wired to the switch so o.k. they just won't be lighted. The switch has three termials, I just used the top and bottom terminals and left the center one empty. I thought the center terminal was to have the switch light stay on?
Then I added a loco to the track and with the switch ON, when the loco crosses the gap (all wheels over) it shuts off. No power to the track and ironically, the switch lights up. I am guessing that the loco is making the connection, I guess shorting? Funny because the circuit breaker did not trip and no magic smoke or anything bad. I did the quarter test before adding the switches and everything worked fine.
So, my question is first does anyone have a wiring diagram of how to cut power to staging tracks using SPST switches? Do I also need to cut the NEG rails to these sections? If so, don't you need DPDT switches?
Thanks for any help.
Casey
yes, you only have to cut power to one rail. i do this on my layout in the staging area
if it like this youll bring the pwr that is going to the track to "power lug" then from the "acc lug" to the track that you want to power.
ground to the other track power wire. so it looks like your track power will then be lighting your switches
later
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Casey,
Your intended approach is correct and should work.
Not sure about your particular lighted switches, but you'd usually have only a center and (top or bottom) terminal on an SPST switch. Did they come with any sort of instructions or diagrams? Can you post a part number or something we can use to look them up?
Short of that (no pun intended), do you have a meter or test light/buzzer you can use to determine which terminals make/break when the toggle is flipped?
Pretty sure the contacts you need are the middle and one of the ends, not the end two. It might even be labeled on the body of the switch itself. Normal SPST switches without lights only have a middle and end terminal. A SPDT would have one on each end plus a middle.
--Randy
Modeling the Reading Railroad in the 1950's
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Hey, thanks guys for the quick answers. I got the switches from All Electronics.
I will try and post a picture. Hopefully I can get that to work. When the switch is off none of the three termials have continuity. When the switch is on, all three terminals are connected. There were no instructions or schematics included.
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just updated my previous post with a diagram
Hey thanks for the diagram, but still not working. I tried hooking the NEG bus to the ground terminal (which makes the light work). Then I hooked the POS bus to the Power terminal and then the feeder to the POS rail to the Accessories terminal. It seems to cause a short, whether the switch was on or off. The loco was behaving eratically and the breaker tripped when the loco was crossing the gapped POS rail.
When you hold a 9v battery to the switch's terminals (the outer terminals) the light comes on when the switch is on and the light goes off when the switch is off. I can't figure out what the center terminal does? With the continuity checker when the switch is on all three terminals are connected, and when the switch is off none of the terminals are connected. Maybe I have the wrong switches?
I suspect you need to find the wiring diagram for the switches.Me, for things like that I use ordinary light switches from Home Depot. They're about 45 cents each and they'll last forever, and cover plates are from six to thirty cents. Just attach to the two non-green screws.
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
ohcase1227...I tried hooking the NEG bus to the ground terminal (which makes the light work). Then I hooked the POS bus to the Power terminal and then the feeder to the POS rail to the Accessories terminal..
I've used this type of switch before, and this is the correct wiring. Are you sure you don't have your pos and neg crossed at some point?
ohcase1227...With the continuity checker when the switch is on all three terminals are connected, and when the switch is off none of the terminals are connected...
That's not really the case(if it was, the light wouldn't light). An unlit lightbuld usually has a low enough resistance to trigger a continuity checker. If you are using a multimeter that beeps for continuity, you can still read the resistance of the bulb off the meter when checking.
Yep, I got it! Turns out the terminal of the ON side of the switch is NEG. Then the POS buss feeder goes to the middle terminal and the POS track feeder to the OFF terminal.
Best part is the light works and no shorting! Awesome. Will be running trains tonight.
I was trying to do testing but these switches are so small I needed those tiny electronic clips to clip wires to the various leads to test. Need to add more of those to my tool kit.
I like these switches because they are small, inexpensive and very clean looking.
Thanks everyone for your help as always!