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Atlas switch machines

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  • Member since
    April 2010
  • 9 posts
Atlas switch machines
Posted by RRRICH_FL on Monday, April 12, 2010 8:52 AM

Hi all!  I'm getting active again in my HO scale model RR endeavor (my layout is in a "train room" building I had built in my back yard -- room dimesions are approximately 25' X 30').  Right now I am using Atlas switch machines (I'll use Tortoises later) -- on my last layout, all 20-some switches and switch machines worked fine.  I redid my layout recently and now have 3 "banks" of switches -- anywhere from 5 to about 10 or 15 individual switches in each bank.  Of my 3 banks, only one works.  I use the small wall transformers to power theswitch machines, and have checked all connections and contacts with a voltmeter, and if I am reading it right, everything has power.  But when I push the buttons on the switch controls, nothing happens, except for the one bank.  All banks are connected the same way:

 wall transformer-------->switch banks------------->individual switches

 Any ideas on what may be the problem?

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, April 12, 2010 9:04 AM

Several possibilities to check:

The wall transformer doesn't put out enough amperage for the switch machines.  They require quite a jolt of AC power (16 Volts).  If the wall transformers are DC, a higher voltage is required in order to provide enough kick to the machines.

The wire you have beteween the turnout motors and switches is not heavy enough.

A broken wire.

If you're using the cheap Atlas push button switches, they are extremely unreliable and have a tendency to stick and burn out switch motors.  A better type of switch would be advisable.

Check the voltage output at one of the turnout motors as you push the button for it.  If you don't get a reading, then either the push button or the wire are the source of your problem.

 

  • Member since
    September 2003
  • From: Southeast Texas
  • 5,449 posts
Posted by mobilman44 on Monday, April 12, 2010 9:31 AM

Hi!

I'm currently hooking up Atlas switch machines, controllers, and relays on my under construction HO layout.  The switch machines & controllers are from 1993-94, and were in use on the original layout until 2008.  During that time, I had one switch machine and one controller go out on me.  Considering I have 35 or so of each, that ain't too bad.

I just finished hooking up 4 crossovers (two # 8 turnouts), so that one push of the button activates both turnouts and a #200 relay that powers the frogs.  My power comes from an MRC Controlmaster I, which is used ONLY for accessories (the layout is Digitrax DCC).  I ran 14 gauge bus wires from the powerpack around the layout, and hooked #18 feeders from there to the 6 connecting sets of pushbutton controllers.  Wiring from the controllers to the switch motors & relays is all color coded #20 wire.  This was my first attempt at using relays (# 8s really need them as the frogs are long), and the things work like a charm.

Trouble shooting your problem should be fairly easy, starting with direct (temporary testing) wires to each of the controllers to verify they are ok, and then to each turnout motor to validate them.  Bypass your original wiring with the test wires, and that should do the trick.  If a lot of the controllers/motors don't work, you could simply have a power source problem.

Wiring, ain't it fun!!!!

Mobilman44

ENJOY  !

 

Mobilman44

 

Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central 

  • Member since
    April 2010
  • 9 posts
Posted by RRRICH_FL on Monday, April 12, 2010 11:05 AM

Thanks a lot, cacole -- the wall transformers I am using are the same ones I used before, and they worked fine before -- had plenty of power for all switches.  Concerning the Atlas push-button switches, that sounds reasonable that they can stick and burn out now and then -- but 30 of them out of 35 or so?  The wire gauge also sounds reasonable -- what gauge do you suggest?  I have been using a variety of 20- and 22-gauge wires for the switch setup, I believe (I'll have to check when I go home tonight) -- maybe I should use 18-gauge?  That seems awful big though, especially for the little screw connections in the Atlas switch controls and switch machines.

  • Member since
    February 2001
  • From: Poconos, PA
  • 3,948 posts
Posted by TomDiehl on Monday, April 12, 2010 7:56 PM

RRRICH_FL

Thanks a lot, cacole -- the wall transformers I am using are the same ones I used before, and they worked fine before -- had plenty of power for all switches.  Concerning the Atlas push-button switches, that sounds reasonable that they can stick and burn out now and then -- but 30 of them out of 35 or so?  The wire gauge also sounds reasonable -- what gauge do you suggest?  I have been using a variety of 20- and 22-gauge wires for the switch setup, I believe (I'll have to check when I go home tonight) -- maybe I should use 18-gauge?  That seems awful big though, especially for the little screw connections in the Atlas switch controls and switch machines.

The wire gauge you're using should be good, especially since they're momentary contact switches, and it's what I've used with Atlas switch machines for years. I even have a couple that throw three of them at once, a pair of switches for a crossover and a Snap Relay.

What you really need is a multimeter, AKA a VOM. First, for each buss, check the input to the switch buttons on the side terminals to make sure you have voltage (just because they worked before, don't assume they still work, remember where the word "assume" comes from). The wall wart should be marked with their output voltage. Then move the meter leads to the top terminals on the button, (center is common) and one side, slide the button to that side and press down. You should also read the voltage. Repeat for other side of the three terminals at the top. This will verify your control buttons are good. For the next part, depending on how far your switches are from the control panel, you may need an assistant. One of you holds the meter leads on the switch machine terminal and the other slides and pushes the button. A voltage reading indicates your wiring is good.

A multimeter can be bought for less than $10.00 at several outlets, and accuracy is good enough for basic troubleshooting like this.

Smile, it makes people wonder what you're up to. Chief of Sanitation; Clowntown
  • Member since
    November 2002
  • From: Colorado
  • 4,075 posts
Posted by fwright on Wednesday, April 14, 2010 9:12 AM

My guess - and this strictly a guess without some more information or measurements - is that you had a marginal working setup before.

The wall warts should be rated between 12 and 16 volts and at least 1.5 amps or 18VA (AC or DC doesn't matter).  Anything less is marginal to throw one switch motor - it may work, but it may not - depending on the friction at the turnout and the motor.  The real problem with marginal power is that is a downward spiral to failure.  The power isn't adequate to throw the switch motor promptly so you hold the button down a little longer to make sure it throws.  The longer duration of the power ramps up the heat in the switch motor, which softens the Atlas plastic casing, which adds friction, which increases the power needed to throw the switch.

If you power supplies aren't big enough (or even if they are), putting in a Capacitive Discharge unit solves many ills.  A CD unit is like the old time flash units for cameras.  They store the energy for the switch trhow or flash in a large capacitor(s).  The recharge current to the capacitor is much less than the current to the switch motor, so it takes longer to recharge than it does to throw the switch.  Normal CD recharge times are a second or two.  The discharge is a sudden jolt of energy which throws the switch with a snap, and automatically tapers off in less than a second as the capacitor's stored energy is depleted.  There is no continuous flow of energy to overheat the switch machine, and the arcing at the release of the push button is also substantially reduced.  Life of both the switch machine and control switch is significantly enhanced.

If the wall warts are adequate (and even if they are marginal), my next suspect would be the banks of control switches and the wiring.  I would suspect some loose connections or introduction of some high resistance within the switch bank.  Or there is a high resistance short circuit which is draining some of the power - a stray strand of stranded copper wire touching the wrong terminal can easily cause this.  With the way the Atlas switch controllers are wired, if there is a problem in one controller, the rest of the downstream controllers in the bank will not be powered correctly.  You may have to separate the banks and power and test each controller individually to locate the problem.

my ideas on what your problems is

Fred W

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