I have this question in to the Atlas support, but thought I would ask here as well.
I am using Atlas Code 83 Snap Switches exclusively on my new layout as a beginner.
After buying and reading the Atlas Guide to Wiring I thought I found a great idea in the book…combining the wiring of two switches that would always be activated together anyway. That way I could save the amount of wiring I needed to thread back to the controller.
When I tested this out, all worked well for the pair of switches, so I wired up 4 pair that this made sense for.
Oh oh. Now that the wiring is in place rather permanently, I find that the pairs do not throw properly. One will always throw, and the other will partially throw or not move at all.
Now here is what I think…
Because all single switches throw properly, and the one double pair with the shortest run of wire to the controller throws properly, I think I do not have enough power running to the switches.
As a test unit I have been using a transformer from an old IHC set. It puts out 16V DC at 400 milliamps.
Is this enough? I bet not.
Unfortunately, right now I do not have any other transformer to test as I am planning to use a DCC Zephyr unit that has no accessory output.
Please tell me what would be a good amount of power to send to these switches from a transformer…and pls. tell me if you think that is my problem.
Otherwise I am going to have to tear up some stuff to redo some wiring that worked in pretest only.
Or it might be simply that the wire is not large enough to let all 400mA get through. Try running a jumper wire from the switch directly to the second set (basically making two feeds to it) and see if that solves the problem.
The best way to know this is to put an amp meter on one of them, see what it takes, and multiply by four.
If you’re trying to trip four pairs of snap switches at one time with an IHC power pack, you don’t have enough power. I use an old Bachmann power pack to power my turnouts and it can only just do three turnouts at once. You will need something a lot stouter. One thing you might try is connecting them in staggered pairs through a relay system, each pair will trip a half second apart, thus relieving the strain on the power pack and giving the switch machines plenty of power. One of the forum electronic gurus must now how to do something like that. Another thing that may work for you is something that a friend of mine did some years back. He had multiple turnouts that had to all be tripped one way to let a train go through the yard. He connected the switch machines through a rotary switch so that when he turned it one way, they all snapped to allow the train to go through and when turned the other way, they would snap back to their previous positions. Each individual turnout was connected to a seperate leg on the rotary switch. IIRC, it was salvaged from an old television set and was used to select the tv channels. You could use something like that to trip up to 12 or 13 pairs of switch machines. Just turn the knob and the turnouts would snap, one pair after another, click, click, click, etc.
Your analysis is correct. You just aren’t giving them enough power. I think the easiest thing to do is to install a Capacitive Discharge circuit. It’s a simple gadget with a few components, and even at Radio $hack it will cost under 10 dollars. Or, you can go out and buy something like the “Snapper” or a similar device for around $35. The whole circuit, though, is a diode bridge, two resistors and two capacitors, as I recall. (If you’re not “electrically inclined,” then this is a great starter project to tune up your soldering skills that you’ll need later, anyway.)
Yes, power is too low. Your 400ma power pack needs to put out at least 2 amps and probably closer to 4 to throw 4 Atlas switch machines simultaneously.
The best solution, for your power pack and the longevity of your switch machines and controller switches, is what is called a Capacitive Discharge Unit (CDU). These store a jolt of power in a large capacitor, which is discharged very quickly when the control button is pushed. The larger the capacitor, the more energy stored, but the longer the recharge time. In your case, with 4 switch machines to fire, I would recommend a CDU with 4700 ufd capacitor.
Circuitron sells one, or there are circuits here (http://home.cogeco.ca/~rpaisley4/CDPSU.html). Building your own is quite simple with just a rudimentary knowledge of what diodes, transistors, capacitors, and resistors are. Mid-page on the link is a current blocking CDU, with or without LED charge light, that would be quite suitable.
Your IHC power pack may be a little slow to recharge the CDU - could be 4 seconds or so. If you want faster, the cheapest and smallest Lionel train set transformers will be a more than adequate supply for your CDU, and some structure lights as well. These are available at train shows for a lot cheaper than a 1.5 amp, 16 volt AC transformer at Radio Shark (if they still have them).
Saying 400 mA is the same as saying 4/10ths of an Amp, and that is not enough, especially at 12 Volts DC. Atlas Snap Switches are made to operate on 16 Volts AC power, so you need a power pack with constant AC output terminals for accessories.
Another option would be to use an old computer power supply if you have one, since most of them have a higher amp rating.
Agreed, it’s not the power, it’s that you need AC for Atlas, Bachmann type twin coil switch machines. The only one that will take bi-polar DC is Kato. Usually it’s 16VAC but you will find the peak is around 20-22 V. I got a Bachmann power pack for my switches and it puts out 18VAC. If you wire in parallel and use AC, there is no reason why it won’t control 2 or more switches at one time just got to watch out for the max ampage they draw. The Bachmann power pack I got will control upto 12 switches at one time although it’s not wired in parallel but rather when using route function in DCC. I think a better option would be get yourself a 500mA or 1A 16VAC power supply and then get yourself a power distribution panel or terminal block and just control individualy that way or I think Atlas like Bachmann can use use only one power feed and then each control block can be linked together in parallel by clicking each control switch together.
I had the same problem. And I am also using the Zephyr, which by the way, I am quite happy with. I bought a small 12 volt power transformer at Radioshack, to power my switches. It was OK for a while, until I hooked up some lights to it. Then I had the same problem, of the switches not throwing all the way. I went back to Radioshack, and got a bigger power transformer. It has 4 amps, and was only $10.95. Now the switches throw sharply, and work fine. I also had a couple switches, primarily crossovers, hooked up to the same button. Get the Radioshack power transformer. It is AC, has plenty of power, and is cheap.
How many volts is this power transformer from Radio Shack?
I have a Zephyr on order from Tony’s, and I’m seeing here that I won’t be able to run power for the switches from the Zephyr. I have several old computer power supplies laying around, so I was thinking of using one of those. A computer power supply outputs DC now that I think about it, so that may be out of the question. Darn. Anyway, what was that voltage output?
Nothing wrong with updating your power, of course, but I’d still recommend the CD circuit, particularly if you are using the big Atlas pushbutton controllers for your turnouts. They have a nasty habit of sticking in the ON position, and you don’t even know it until the smell tells you it’s lights out for one of your switch machines. The CD circuit gives you some protection from this by limiting the current, even if it’s left on.
Radioshack has an assortment of 12 volt, AC transformers for various projects. They come in various amp ratings, and all are cheap, compared to official model railroad items. The transformers range from 400 miliamps, to about 4 amps. They can be used for switches, building lights, or anything that requires 12 volts.
Actually, old computer power supplies are quite handy for a variety of accessory purposes. Your Atlas switch machines will operate quite happily on the 12 volt rails, provided there’s a couple of amps of current available. The switch machines and light bulbs all operate equally happily on both AC and DC. Motors and LEDs require DC.
yours in wiring
Fred W
Both the 12V and 5V rails are useful for lighting structures and driving LEDs.
Thanks Fred. I didn’t realize the Atlas switches will use DC. I was just going by what I’ve read here. If they work on DC, then I’m good to go. Most computer power supplies has one 12V rail at 8-12 amps. The other rails are 3V and 5V, but those are 1 amp or lower.
I have the Zephyr and use atlas power packs to power the switches. You will also see that you can use the power packs to run additional trains. I have 2 set up.
As far as the multiple switches are concerned, I have attached several together and was having the same problem with power. I bought the Capacitor Discharge unit MKII to solve this problem. This has given my switches the extra power they needed. I couldn’t figure out how to make one and solved my frustration. Hope this helps.