Atlas Switch Machine Burnout

If this (burned up) happened while you were using the same voltage that you had previously been using without problems, the only way I can think of is that the voltage remained applied to the switch machines for longer than a second or so. Perhaps the toggle switch failed?

I have 48 Atlas turnouts, which I actuate with either a toggle switch on the control panel, or with a DCS AIU, and have no problems at all. I also have several pairs of turnouts connected in parallel to a single toggle, as the turnouts are in crossover configuration, and no problems with these either.

I am not aware of any differences between the old and newer models. To prevent the burnout from happening, make sure that the voltage pulse does not exceed one second in duration. I use 18vAC, but I believe some people have used as high a 24vAC without problems - as long as the pulse duration is short.

Alex

Thanks Alex,

I'm pretty careful to restrict my push on the toggle to a quick tap and am the only operator. Voltage is about 16vAC. What bugs me is that they were both fine the day before and then both dead the next. I would have to agree that it must have been something I did -- just can't figure out what. I'm happy to get your input on using the DCS AIU without problems as I'll be transitioning to that in the near future.

Stuck button.  Doesn't take too much time to burn an (Atlas) coil that is designed for momentary power.  The problem eventually generated the Atlas 6924 relay board, that has a time-out feature and other features that deal with switch problems.

Atlas  6924 board

Time out feature to inhibit switch motor burn-out,  Auto-electric non-derail,  Power routing to eliminate switch dead spots,  6931dwarf light control.

I know the 6924 board is for non-derail, and can also keep the coil from burning out, but I only want the time-out feature.  Do others still only use it for thus, or is there another less costly item to use?

A capacitor discharge power supply is a good simple way to limit power to switch machines. It just requires a diode, resistor and large capacitor. The recharge time depends on the size of the resistor and capacitor, maybe 2 seconds or more. From what I remember off the top of my head, try a 100-ohm 1-watt resistor, 1A diode, 6800mfd capacitor. I use misc secondhand components for my projects; the values don't have to be exact as long as they are adequate for the job.

As already stated the switch button probably stuck at some point. Atlas had a recall on their #57 switch control a year or so ago (if you are using these). I believe it was due to a sticking problem. I think some folks use momentary 'on-off-on' toggles that automatically spring return to the center 'off' position. I use the #56 switch controlers that came with the switches. This is a problem with all twin coil switch machines, not just Atlas. The DZ1000s are a different type of switch machine, they are not twin coil.

As Mike CT stated above, the 6924 boards are a good way to prevent this with the Atlas switch machines. I bought a couple and was going to use them, but after getting all set up decided I didn't need them. Also, here is a link to a capacitor discharge circuit that can also be used (there are many other examples out there as well). I have not tried using one, but I have tried some other projects from this site and they worked as described. I also think this is a reputable site. Capacitor discharge is supposed to be a good way to prevent burning up the twin coil switch machines. I believe this method has also been used in the smaller scales for a number of years now. If I ever start having problems with burn outs I will probably give one of these capacitor discharge circuits a try, or use one of the 6924 boards.

My layout is much smaller, but like Ingeniero No1 above, I have not had any problems with my any of my dozen or so Atlas switch machines. The exception was some I got with used switches that didn't work when I got them, which for the most part I have replaced with new ones. I also had to repair some other things on the used switches, which I was able to do, and Atlas had all the parts I needed. They were very helpful in getting me the right parts too. I have not had any problems with any of the Atlas switches I purchased new from my LHS and all my future switches will be new ones.

I started out wanting an AIU, but decided I like the switch controls at the switches. I'll probably still add the AIU someday though for route control and other things. I have an expansion and some revisions planned, but that's kind of been on hold for a while now. When that gets going again I'll probably add an AIU or two.

Edit: Looks like Ace posted a simpler capacitor discharge circuit while I was searching for one to link to. His may be a better idea and easier to construct.

I am in the design and initial construction phase and have been buying up 6924 units as I see them on eBay.  The 6924 has lots of applications and mine will be tied in with the signals to perform various functions.  The fact that the 6924 can be operated by an AIU and/or a pushbutton means that in both remote and local operation of switch machines the coils will be protected AND the signal system will operate properly to ensure safety.

GENRAL NOTICE - Safety is of the first importance in the discharge of duty.  Obedience to the rules is essential to safety.  To enter or remain in the service is an assurance of willingness to obey the rules.

I'm hoping that my friend Peter will weigh in on this. He toasted quite a few of these things. 

Quick fix is to install DZ1000 switch motors.  That's what I did.

As usual, ask a simple question on the forum and get a whole bunch of great answers! For now I'm going to go with bad toggle switch. On inspection the back and forth motion of the suspected switch was very stiff compared to other Atlas toggle switches on the layout. I'll keep an eye on it from now on as well. More than once I've hit the toggle when there were cars on the track that blocked the switch travel. I like the more elaborate toggle that Atlas has with the red and green lights but can't seem to find any on line at the moment.

Many thanks for all of the informed responses.

Forgot to mention above that some of the used #56 switch controllers I got were 'sticky' or just did not work very well, so I replaced all of those that did not operate smoothly and without problems. All of the new #56s I have purchased have worked just fine so far. If you have any others that are suspect I would replace them as well. The #56 is the one that's included with new switches.

The more elaborate Atlas toggle with lights is the #57. That is the one they recalled a year or so ago (could be longer?). I don't know if they will get remade or not, haven't heard? I had just purchased some of those from my LHS and had a couple installed. About a month or so later my LHS told me there was a recall on them and to bring them back for a refund. Haven't seen another one since then. The #57s were very nice and the indication lights were a nice addition as well. I had not had any problems with them, but returned them anyway.

RTR12,

The #57 is the switch I was trying to think of in my last post. I have three and really like them. Shame that they were discontinued.

S

Tortoise used here.  I get a burn out proof system each with a pair of S.P.D.T. built in switches for as needed polarity correction.  Great for double cross overs,  slip switches,  single switch frog polarity, signaling, etc.  Not cheap, not expensive, just right all things considered.

I don't know if the #57s have actually been discontinued permanently? Just that they were recalled. I thought it was just the one batch that mine were from, but maybe not?

Scott:

I use diodes ( I believe 1N4001) in line with the power wire to the switch machines. The diodes rectify the voltage waveform so that the machines don't heat up that fast. This by itself won't cure a sticky controller from burning out a switch motor. In combination with the diodes I replaced all #56 controllers with 1 amp SPDT momentary toggle switches.

It was always the #56 controllers that seemed to stick and burnout switch motors. I have and still use about 10 #57 controllers (about 4 years old). I have had no issues with them but given the posts above concerning a recall I may have to double think those.

I am slowly moving from Atlas O switch machines to Z-1000 motors. However I still use the SPDT toggle switches with those motors. The diode is not necessary here and in fact Dennis Zander has said not use the diode since the Z-1000 has it's own rectifier built inside and using an outboard diode will screw up the motor.

Dose anyone have any information on the #57 recall - how far back it goes?

Joe