EDIT: Here is the solution. The original post is bellow the dotted line. Simply put, a Capacitive Discharge Unit (CDU) is what you need for that. The wiring itself is almost exactly like the standard wiring except that: 1) You just install the CDU between the AC power source and the control box (remote switch button) and 2) The switch machines are then wired, in parallel, to the control box. That is all there is to it. See the linked pictures for the wiring scheme I used as well as a photograph of the actual wiring. Wiring scheme Photograph of the actual wiring For reference, this is a list of the hardware I used: Power source: Model Power "Electro 1.3" (Model No.3800) CDU: Miniatronics PDC-1 Control box: Atlas #56 Control Box Switch machines: Atlas N Code 55 Under-Table Switch Machine (item #2065) Wiring: AWG22 (I will use AWG18 or maybe even AWG14 for the permanent installation on the layout --so should you-- plan for 2 AMPs per switch machines plus wire run length.) EDIT2: added a YouTube video of the system in action. [ame="http://www.youtube.com/watch?v=gXBwrPnj2bU"]YouTube - 4 switch machines controlled by a single button[/ame] ---------------------------------------------- I'd like to wire my double crossover to a single switch so that all turnouts move from the single push of a button. Such a piece being what it is, there is only 2 possible combinations I will ever need: all closed or all open. Therefore, wiring all 4 turnout motors the a single switch seams like a logical thing to do.. or is it? The double crossover itself is made off of 4 Atlas code 55 #10 turnouts an a 11.25 degree crossing. The switch machines would be Atlas "N code 55 under-table switch machine" (item #2065) So, my question is how would I do that? Surely, it is not as simple and straightforward as wiring all the switch machines to a single switch and call it a day. My pinky told me there is a catch it there... but what would it be? Thanks you very in advance
Theoretically, it shouldn't any more complicated than you described, if your only requirements are for either all closed or all open. They will all be executing the same action at the same time, so there's no polarity issue. If you're nervous about wiring everything in parallel, you might want to get a 4-pole switch so you can have four separate circuits being switched at the same time, but personally, as an electronics tech, I think that would be overkill.
My only concern would be if these are snap action motors the instantaneous current draw will be pretty high. That has a few implications. One is that the switch or pushbutton will need to have an adequate current rating to prevent early failure or welding up. The 4-pole idea above should get round that OK, but may make for a rather wide switch if you are making a small control panel up. Another is that the power supply may not have the oomph to provide the instant power and therefore won't reliably operate all four motors. You may need an uprated transformer or CDU. Finally, tying with both of the above points, the wring will need to be substantial to avoid too much volt drop, which would again reduce the power available at the motors. If they are slo-mo motors, like Tortoise, then none of the above applies
I installed Peco 55 xover using 4 Peco switch motors. Did seem to have the problem that Mike mentioned. I split the control into 2 parts , x or straight running 2 motors at a time. I don't use control switches. I use a studs on my control panel that I touch with a control "wand". For this x switch I use 4 studs. For a regular switch I use 2 studs. I use the Peco addon contacts to run indicator LEDs for the x over. Found this non reliable for other switches so used microswitches top mounted. Hope this helps. Dave B PAT in Montreal
If the straight track sections are gapped (the Shinohara double crossover is constructed like this-I don't know about Peco's), then like Dave B. posted you really only need to control 2 switch positions at once (crossing over or running straight through). As long as they're electrically isolated the other switch positions won't matter and they won't interfere with running your trains either. It would be just like controlling two single turnouts point to point from the same relay, times two. Any normal switch controller should be able to handle that load. Just don't hold the contact relay for two long or you'll burn out the coil. Good luck.
Great answers. Me like this place! :thumbs_up: Perhaps if I use a good old DC power pack exclusively for powering the switch machines then I won't run short on current? The machine's documentation mention "designed for momentary 16-18 volt AC operation" and "that a separate power supply of at least 25 watts (2 amps) capacity be used to power the switch machines". Im thinking about using capacitors to prevent burning the solenoid coils and/or ensuring that enough juice is available. I think I heard someone said he uses this but I can't remember exactly. Obviously tho, if the most reliable way is to simply use a switch control box per machine then so it will be. Still, switching the whole crossover with a single button sure sound good to me! Thanks again.
Capacitive Discharge Unit for turnout power If you find that there is not enough power to move the 4 motors at once you can use a Capacitive Discharge Unit. This unit will protect the twin coils from overheating by supplying a short burst of current and then shut the motor circuit off. Only when the momentary button is released will the unit recharge to allow another turnout operation. In conjunction with a diode matrix you can create very complex routes using single button presses. From your description you should not need a diode matrix, however. Miniatronics has a Capacitive Discharge Unit #PDC1
Using a PSU exclusively for switch machines is certainly good practice as it avoids any spikes or dips affecting your train ops, lighting or other stuff. So to drive four simultaneously you need a 100W (8Amp) PSU. Unless you have one lying around, that will be expensive and raises other issues about fault protection (like when something sticks on). I'd definitely go the CDU route - the one TrainGuy suggests claims to do up to 10 machines (which sounds a lot), or you can build your own quite cheaply.
A CDU would definitely be of benefit here, as it stores energy over time and discharges it only as needed, over a short time. Now there's something I hadn't realized - how much those suckers draw. I have to admit that I am re-entering the hobby after 30 years (I was still a kid), but a 2 amp power supply to power one machine? I will have to look into that further. It sounds a little bit overkill to me, but then I suppose the manufacturer doesn't want customers' power supplies letting their smoke escape, and add some substantial margin... (and once you let the smoke out of something electrical, it stops working) At work we use some very heavy contactors in the instruments we produce, and they draw at most 200 milliamps on surge. They make a very solid thump when they operate. That's why I have trouble wrapping my brain around the 2 amp figure. I want to start building my layout soon, and if I have to plan for a private nuclear power plant just for my turnouts, I'll either be going manual or with my own power control/motorizing solution. Working in electronics has its advantages - I'm already designing my own throttles and power distribution system, so one more or less module...
OK. I ordered a Capacitive Discharge Unit #PDC1 from Miniatronics just now. The rest of the supplies are due to arrive next week (the rest of the turnouts and switch machines, among other things --I bought all she had left in stock!) so I'll let you know how it goes in due time.
I still don't see where it is necessary to operate all four switches at once. You have only can cross over in one direction at a time. If the other frogs are isolated, it won't matter whether they are open or closed when your train crosses over.
Yes, but how much do they cost compared to a model train switch motor? I don't know about the Atlas ones, but the Pecos are little more than a pair of wire coils with a loose fitting solid bar down the middle. They don't have the tolerances to pull reliably at low currents. (I think you may find the travel is also shorter on the contactors which means a different configuration is used for the magnetic circuit.) I think the OP just wants to keep operating things simple and just have one switch (or pair of buttons) to set straight or crossover. Its quite a good idea - just that the impulse (impact might be a better name) motors are ****. (One reason I went the Tortoise route.)
Cost is comparable to the slow-motion types. Not the point. Neither is travel. My issue is electrical-mechanical. The coil in the contactor moves four sets of 20-amp contacts at once. These are industrial units with 12 volt coils and are big - about a 2-inch cube. And heavy. Still, only 200 milliamps to move all this mass (and hold it against the springs). That's why I find 2 amps excessive for a single switch machine. I'll have to buy a basic machine and make bench tests on it to see exactly how much current it draws, on what time scale, and what the surge current is. Sorry for asking the questions and embarrassing myself with my ignorance. I'm old-school, i.e. to know something I either ask someone or look it up (darn, I wish I was psychic or had Bluetooth installed in my head... bad genes, I guess...).
Look like Peco and Atlas share the same technology. See attached picture. it's from the documentation paper that came along the Atlas N code 55 under-table switch machine. I post this just in case it's useful to someone. BTW I got my first loco yesterday and I, obviously, have to tell the world. It's an MP15DC CP Rail #1442 decoder equipped and it's flippin' cool :tb-tongue:
More info. I'm using the AC from one of my cabs which is an MRC 350 Tech4. As said earlier operating 2 Peco switch motors at a time. You can control with 1 spdt switch and a momentary action switch, thats all or 1 momentary spdt switch with the center position off. For the track wiring the straight has gaps so added no special wires. The only ik is running slow. some short wheelbase engines stall at x over. Dave B. PAT in Montreal
Congrats on your loco! :tb-biggrin: Of course you have to tell the world... it's not just your right, it's your duty!! And what you describe about the switch machines is about what I just found - I bought one today (Atlas under-table) and measured the DC resistance as 6 ohms - i.e. 2 amps at 12 V DC or AC RMS. The resistance would probably be marginally higher at 60 Hz AC. In any case, there's up to 25 watts going through these flimsy things - not good if something stays stuck. Now I'm starting to understand why the power supplies on my layout (30+ years ago) smoked regularly. My dad obviously didn't realize this when he wired the whole thing up. In its most basic form, it's a failure-prone system. Now I'll put my electronics R&D job experience to profit and design a fail-safe system to control these hungry little beasties. Or at least find a cheap, lower-power alternative. There's an electronics surplus store about ten minutes stroll from here and I've seen small, inexpensive solenoids there. It's worth a look. At the very least, it will be fun to try. :mwink:
OK Im gonna need a drawing to figure out how to wire the things together.:tb-embarrassed: Searching the internet is fruitless. I can make it work for one switch machine but not two or more. I need four! See attached drawing. This wiring scheme is fail. Thanks you very much in advance!!!
As far as it goes the diagram looks OK (it lacks any info on what each terminal does). If by 'work for one' you mean that it works with just one motor connected, but when you connect more in parallel they don't throw, then it sounds like either, the CDU you have does not have enough oomph to drive more than one, or, your wires are way to skinny. (You need some substantial copper in the lines between the CDU and motors).
An update on the experiments I've been doing on the test machine I bought a few weeks ago. I managed to get it to actuate rather well at 5 volts DC, and even down to 3.5 volts DC. At those voltages, it draws less than one amp. I'm working on something powered by a surplus computer power supply (from a dead computer), using a 555 IC wired as a one-shot timer controlling a pair of power transistors, one for each direction. With this the machine gets just a short impulse, enough to actuate it. Activation is by a two-position momentary switch (center off), which also controls the power to the transistors - so when the switch is released, there is no more power going to the machine, even if something shorts or stays stuck. Now it's just a question of finding the right impulse length to guarantee a solid movement.
I used skinny wires indeed. These are what the switch machines are shipped with. Solid AWG 30 or maybe even smaller. I can't tell from eyeball measurement but it's pretty damn close to what I have inside my phone's wall sockets. The CDU documentation claim it can power up to 10 switch machines so it must be the wiring. I found a diagram I believe may be what I need to do. Here and here) Clearly, my wiring was way off. :tb-embarrassed: I'll keep working on it.
