I have a swing down section that is unpowered and I need to get power across the section. I've been considering micro switchs to connect each part of the layout to the drop-down. I think I have it figured out, but I'd input about exactly how to do it and what is the best kind to use.
For what you're describing, you don't need any microswitches. If you want power to the "bridge", connect each rail on that section to the track leading up to the hinge, using a flexible connection.
If you also need an electrical jumper, via the bridge, to power the other side, you will need to add electrical contacts. I've done that on my layout that has 4 lift-out sections for door and window access. I used brass strips, positioned on the bottom of the lift-out, and on the top of the lift-out support. I don't remove them very often.
If I were to have to open and close them more frequently, I think I would change to what's called "wiping" contacts, where the metal slides mostly, instead of just plopping down. This makes the contacts sort of self-cleaning.
I'm not thinking of any off-the-shelf easy solution for the contacts--I think you'll have to make your own.
You CAN get fancier with automatic cutoffs so a train doesn't run through an open bridge, but you didn't ask that.
Ed
Many many years ago I had a lift up section that I used a switch to drop power to the track a couple of feet before the big drop. Any micro switch would work, in my case I needed to drop the power to two tracks so I had the switch pull in a 4PST relay that dropped power to all four rails when the bridge was up. Never had any thing take the big drop. They make several versions of micro switches, some no activating lever some with long and some with short levers as well as some with rollers. Most are 3 to 6 amp rated.Mel Modeling the early to mid 1950s SP in HO scale since 1951My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Aging is not for wimps.
OP,
A microswitch doesn't deliver power anywhere, it interrupts power. Wires deliver power.
If you are concerned with delivering power in and around your ("unpowered") movable section, you need flexible wires and/or electrical contacts.
If you are concerned with interrupting power, as in when the section is not in place, THEN you would use microswitches IN ADDITION to the flexible wires and contacts.
You might want to clarify your needs and goals.
7j43kA microswitch doesn't deliver power anywhere, it interrupts power.
Ed you're right. A Normally Closed micro switch will break the circuit when pressed. But if it is wired Normally Open then it would complete the circuit when pressed.
-Matt
Matt,
My point is that you only need a switch if you wish to be able to turn the power off. If you DON'T wish to turn the power off, you DON'T install a switch at all. You just run a wire.
If the OP only wishes to run power to some sections of track that don't have any (as he stated), then he doesn't need a switch, micro or otherwise. He needs a wire.
I look forward to his showing up and clearing the air on this.
The swing up section doesn't need the power off, the approach tracks do.
The microswitch allows lifting the section to be a one step process. You raise the swing up and power is cut. If you have to do two things, raise it and unplug or turn off a switch, Murphy is always looking over your shoulder.
How far you need to cut power on the approach depends on keep alives and momentum.
Henry
COB Potomac & Northern
Shenandoah Valley
I think we all are confused! Which way is this lift-out section swinging? Up, down, or is it being lifted out completely?
From the original post:
"I have a swing down section that is UNPOWERED and I need to get POWER across the section."
(added capitalization).
The above seems to be describing the OP's problem.
So he needs to get power to the swing down section, because he doesn't have any right now. I think we all agree that power is useful for running trains.
And it looks like he needs to get power to the "other side" of the swing down section. Also to run trains.
I see nothing there that calls for a micro switch.
I DO see using a flexible connection at the hinge point of the swing down section. Powering the "other side" could be done as I described earlier, or with a simple cord across the gap.
It's looking like I'm the only one posting who actually read what the OP said.
mthobbies I think we all are confused! Which way is this lift-out section swinging? Up, down, or is it being lifted out completely? -Matt
If you read the original post, you will see him talk about a "swing down section". Not a "lift-out" section. And presumably it swings DOWN. 'Cause he said so.
Most or all of us who have responded would want a cut-out for when the bridge was out of alignment.
Possibly that's what the OP would like, in addition to actually powering the tracks.
I'm sure he'll show up real soon and fill us in on all this.
I thought it was clear that I need to get power to a section that has no power when open for in/ out access to the layout. I thought microswitchs could be wired like any contact so that when two were making contact power would move from one to the other. Maybe what I need has already been suggested as a simple metal contact for each rail where they meet when the lift up is closed.
Mike
mreagant I thought it was clear that I need to get power to a section that has no power when open for in/ out access to the layout.
I thought it was clear that I need to get power to a section that has no power when open for in/ out access to the layout.
I thought so too. Although I'll point out that it also has no power when closed. Clarity, clarity. But then you said the magic word "microswitch".
I thought microswitchs could be wired like any contact so that when two were making contact power would move from one to the other.
Microswitches aren't contacts. So, no, you can't do that.
Maybe what I need has already been suggested as a simple metal contact for each rail where they meet when the lift up is closed. Mike
Maybe what I need has already been suggested as a simple metal contact for each rail where they meet when the lift up is closed.
Yup. That'll transmit power across the chasm. And shut it down when the bridge is out of position.
Thanks for getting back and saying all this.
mreagantI have a swing down section that is unpowered and I need to get power across the section. I've been considering micro switchs to connect each part of the layout to the drop-down. I think I have it figured out, but I'd input about exactly how to do it and what is the best kind to use.
I think I have the answer you need. I hope you can understand my sketch.
I had a drop down section for the "Spare Bedroom" layout I built. I later removed it and made the layout point-to-point.
Anyway, the drop bridge section is shown in the drawing. It was supported by two door hinges. The hinge on the right had a removable pin. When the pin was pulled out, the bridge would drop down out of the way.
The red and blue wires show the power bus for the track. The bridge itself is unswitched. It can have power in the down position to no effect. There is no reason to disconnect power from the actual bridge section.
The microswitch controls about 12 inches of track on either side of the bridge. When the bridge is down, one rail is disconnected from the circuit so the train will not move through it and crash to the floor. One microswitch can be used to control the approach tracks on both sides of the bridge.
The gray block on the bridge contacts the microswitch when the bridge is in the upper position and closes the connection between the common (C) and normally open (NO) contacts. There is no connection to the normally closed (NC) contact on the microswitch.
The switched wire from the microswitch is shown in orange.
If you click on the image you should get a better view.
I use inexpensive Microswitches From Amazon. These have worked very well for my model railroading needs, and they cost less than 50 cents each.
I also use a contact plate and several microswitches to turn on and off tracks from the turntable.
These are very useful devices. I have a couple hundred on hand.
I hope this helps.
-Kevin
Living the dream.
mreagant I thought it was clear that I need to get power to a section that has no power when open for in/ out access to the layout. I thought microswitchs could be wired like any contact so that when two were making contact power would move from one to the other. Maybe what I need has already been suggested as a simple metal contact for each rail where they meet when the lift up is closed. Mike
I decided to add a bridge on a piece of 1/2" plywood to span an aisle. I would call it a "lift out" section, since I designed it to drop into place and then lift it back out when desired rather than duck under it.
To provide power, I added feeder wires to the track on the lift out section. These wires extended to both ends of the lift out section and were screwed into flat brass plates. When the lift out section was dropped into place, there was a matching flat brass plate on the edge of the layout on either side of the aisle. Those two brass plates also had wires screwed into them to provide power from the main buss.
The lift out section was powered in that manner. Worked like a charm.
Rich
Alton Junction
mreagantMaybe what I need has already been suggested as a simple metal contact for each rail where they meet when the lift up is closed.
'Morally' you treat the track in the bridge as supplied by its own feeder, and that should have its own soldered connection to rails and dedicated wire pair. Whether you interrupt one side of this with a microswitch that opens when the section is not perfectly aligned to Run Trains is an option, and likely electrically better than 'open contacts' (the switch likely will have noncorroding hard faces on its enclosed contacts, for starters) and you can make break over very finely adjustable more easily with some types of switch.
On my four lift-out sections, I did exactly what Rich did. Mine are all double track on up to 4-track. I built a shelf on the bottom of each fixed end, and I placed an array of 1/32" x 1/4" strips there. And matching ones on the bottoms of the lift-outs.
I bent the ends "up" slightly to provide spring pressure on the contact surfaces. I've had this system up for about 20 years now with no problems. That said, I VERY rarely remove the lift-outs.
For something that was constantly being opened and closed, I think "wiping" contacts would be better. Here's an example of wiping contacts:
Note that the moving arm wipes the fixed contacts as it closes. This helps keep the contacts clean.
I suppose you could swipe the contacts off of knife switches. I see in photos where some of them have the parts held down by little bolts.
I'd caution that SOME of these knife switches might take more pressure to close than you care for. I doubt you need something heavy duty. You're not even using the contacts to switch a current.
You could also make your own out of some of that 1/32" x 1/4" brass strip.
It's certainly true that these contacts could affect the alignment of the drop-down section. You might need alignment pins also, if you don't have them already.
If you went with the flat contacts, as Rich and I did, the worst case is that you'll be using your Bright Boy now and then.
Our club lift bridge locks in place with two metal toolbox latches. One on each side of the bridge. Power is connected through the latches when the bridge is in place and locked. Disconnected when open.
Martin Myers
7j43k On my four lift-out sections, I did exactly what Rich did. Mine are all double track on up to 4-track. I built a shelf on the bottom of each fixed end, and I placed an array of 1/32" x 1/4" strips there. And matching ones on the bottoms of the lift-outs. If you went with the flat contacts, as Rich and I did, the worst case is that you'll be using your Bright Boy now and then.
The first photo shows the aisle to be spanned by the lift out section, at an angle no less. I used this lift out section as a reversing section to change the direction of changes. I did not originally plan this when I first built the layout. It was an afterthought, so it was not easy to find a way to reverse trains on an existing layout.
The second photo shows the completed lift out section containing a single track bridge. I later converted this setup to a double track bridge.
The third photo shows the metal contact setup on the left side of the lift out section.
The fourth photo shows the right side of the lift out section. I had forgotten that the right side did not have metal contacts. Turned out, I didn't need them on that side.
Just like Ed, I did not need to remove the lift out section very often. I mostly did so when I had to work on the far side of the layout and I got tired of ducking under the liftout. Also, when my young grandson would come over to visit, he would race full speed right under the liftout, causing me a near heart attack. So, I got smart and removed the liftout before he arrived for a visit.
mfm37Our club lift bridge locks in place with two metal toolbox latches. One on each side of the bridge. Power is connected through the latches when the bridge is in place and locked. Disconnected when open.
The idea of using the brass toolbox latches as electrical contacts is ingenious. Keeping the contact good between the saddle and locking bail ought to be relatively straightforward, although if the latch came lacquered from the factory a little judicious removal and cleaning at the various contact points would be advisable.
I presume that the actual alignment is made with adjustable plates and that some sort of pin-and-socket arrangement near track level is used for fine alignment of track ends. I further presume that if only one latch is used per side that the 'other' contact is made through contacts or pins up near the track -- what arrangement was decided upon? Only one pin or plate per end would serve for electrical return...
mfm37 Our club lift bridge locks in place with two metal toolbox latches. One on each side of the bridge. Power is connected through the latches when the bridge is in place and locked. Disconnected when open. Martin Myers
I like it!
Rich,
I think I would have taken the coward's way out: a "trough shaped" span of black painted plywood (I'M NOT REALLY HERE!).
Since my at-home layout is so far just a giant test track, it's all plywood painted white (not black).
That is/was a nice looking bridge.
I eventually converted that single track liftout to a double track liftout. Each track on the liftout became its own reversing section.
Well, I've learned quite a bit from this discussion and I want to thank everyone for the ideas. So we all end up on the same page, let me clarify a couple of things. The section is hinged on one side with door hinges and drops down to provide access to the door. When lifted it is locked in in position with two slide latches underneath. I have figured out how to flow power to the section with the hinges using simple track wireing. What I'm struggling with is how to transfer power across the section to the other side when lifted in place. I didn't mention that two tracks enter on each side. In order to avoid running off the layout on that side I isolated about six inches of track on that side from the main layout with insulated rail joiners. I thought I would be able to use the powered lift up section to transfer to the isolated sections of track there by powering the small unpowered section. The reason I titled this post "microswitchs" was I thought that when two opposing switches came in contact and were connected by that action the power could be transferred.
Whew! Lots of good ideas and now I'm headed to the train room to evaluate what the best solution is.
Thanks to all.
I'm surprised the slide latches give good enough railhead alignment -- they may start to sag over time. Same with the slip in the hinges over time. Hence the various advice about V-channel lateral alignment, adjustable plates, engaging pins etc. to get both ends precisely located when closed.
Probably the 'best' way to get power is to treat the approach, the door, and the opposite side track sections as being fed by drops from the same feeder... and wire them all as drops from a common feeder, routing wire around the benchwork, through a channel on the floor, using flexible wire as indicated above to power the door, etc.
Note that you can happily run feeders across the underside of the bridge in 14 gauge and design the contacts at the end of the bridge to have corresponding area, connecting to more 14ga feeder on the other side. Then just wire up to the individual rail or track segments, which will then be only a few millivolts at most different from each other. This may involve a couple of amps at 14-15V, but that's not really a contact hazard, and then you can use a micro switch of appropriate rating to interrupt the hot feeder going to the door as a safety cutoff for the approach, the door, and the section beyond the door.
I've been trying to make a way to go under the fold down section and connect when it's up by using some type of connective like RCAs. Now I realize I can go over and around the exit door frame. It'll be a lengthy piece of wire, but I'll figure it out..
mreagant by using some type of connective like RCAs.
My drop down uses the once-common "Cinch-Jones" plugs and sockets.
Cinch-Jones by Edmund, on Flickr
This way I have plenty of circuits for turnout (Tortoise) supply, lighting DC, signals, main track buss, plus the section of track directly connected to the bridge.
Plus, a Cinch-Jones can only be oriented one way so circuit integrity is good and they will handle something ± 10 A.
I use one pair "looped back" so that when the plug is disconnected a series circuit opens. This opens a relay that A, kills the track for about six feet either side of the "chasm" and also drops the signals to red.
DB_9 by Edmund, on Flickr
DB_7 by Edmund, on Flickr
OvermodI'm surprised the slide latches give good enough railhead alignment -- they may start to sag over time. Same with the slip in the hinges over time.
My drop bridge is twenty-six years old and I haven't detected any sag, wear, displacement or even thermal shifting. I used a commercial steel hinge that has ball bearings and adjustable thrust washers. We DID have an mb 5.0 earthquake near here but that was in '86 just before I began the layout.
The opposite end, however I use two dowel pins plus locking set screws to adjust the Z plane (rail height).
DB_5 by Edmund, on Flickr
Good Luck, Ed
gmpullmanThe opposite end, however I use two dowel pins plus locking set screws to adjust the Z plane (rail height).
Ummm... Wow!
That is amazing.
SeeYou190That is amazing.
Thank you, Kevin
I had some help from the GE machine shop, too
This bridge spans the doorway into my workshop and has masonry walls on either side of it although there is 2 x 4 wood framing over that. Still, there has been very little adjustment ever needed and I'm pleased with the operation.
DB_3 by Edmund, on Flickr
DB_6 by Edmund, on Flickr
It was just luck that the bridge, when down, fits into its own little out-of-the-way niche and isn't prone to bumping. The bridge itself is made of furniture-grade maple with the track base dadoed into the side rails.
I recommend a drop-type bridge whenever practical over a lift-up type. Seems to make more sense to me, anyway.
Unless, of course the FORCE be with you and you can have one of those superheterodyne virtual styles I read about in M-R some time back
gmpullmanI had some help from the GE machine shop, too
That is the one thing I miss most about my old job.
I had the tools at my disposal to make anything I could ever need.
... and people who knew how to use them!