Atlas snap switches

SR39

New Member
Jan 14, 2007
37
0
6
84
Upstate, SC
Does anyone know what the neutral wire is on an Atlas snap switch machine. I am changing to DCC and need to know for wiring a stationary decoder. The wires are green, black and red. The black is in the middle but I don't want to assume that it is the neutral.
 

mjm

New Member
Aug 18, 2009
4
0
1
Iowa
Turn outs

Your turn outs will all work with the Black neutral. I have to warn you and others that have had a scary experiance with Atlas turn outs, for some reason when closing two to the turn outs they melted, without warning two more melted. My layout is abut 1 1/2 years old, I pulled the motors and talked to my dealer, he had no answer and said to call Atlas, I did and they wanted the turn out, so Isent then to them. I just recieved new onew with no explanation to what happen. I beieve the switches stuck open when moving from one side to the other causing a reverse flow of current and a short, other then that I have never had any problems with Atlas turnout on my N scale and HO scale layouts. If someone has a answer, tell me.
mjm
 

pgandw

Active Member
Jul 9, 2005
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0
36
Your turn outs will all work with the Black neutral. I have to warn you and others that have had a scary experiance with Atlas turn outs, for some reason when closing two to the turn outs they melted, without warning two more melted. My layout is abut 1 1/2 years old, I pulled the motors and talked to my dealer, he had no answer and said to call Atlas, I did and they wanted the turn out, so Isent then to them. I just recieved new onew with no explanation to what happen. I beieve the switches stuck open when moving from one side to the other causing a reverse flow of current and a short, other then that I have never had any problems with Atlas turnout on my N scale and HO scale layouts. If someone has a answer, tell me.
mjm

The usual failure mode for Atlas switch machines is a sticking button on the controller - Atlas controllers are known for this. The switch machines can only tolerate the current being on for a second or so - then they start to melt.

Failure is more likely with a marginal power supply and/or trying to throw 2 turnouts simultaneously. The power supply can't give quite enough current/voltage to snap the switch machine(s) over, so the buttons are held down slightly longer than they should be to get the turnout thrown completely.

The solution is to install a Capacitive Discharge Unit (CDU). A CDU provides a big jolt of energy to the switch machine from a charged capacitor that allows the switch machine to "snap" over. The jolt tapers off very quickly as the capacitor discharges, protecting the switch machine from overheating. The CDU recharges in a second or two, and then is ready to throw another turnout. Most CDUs will easily throw several switch machines at once. A CDU is very similar to the electronic flash unit in your camera.

Circuits for building your own CDU can be found here - http://home.cogeco.ca/~rpaisley4/CDPSU.html - and elsewhere on the web. A CDU is a particularly simple electronics project, but you can also buy commercial units from Circuitron.

hope this helps
 

mjm

New Member
Aug 18, 2009
4
0
1
Iowa
Atlas turnouts

Hey thank you for your help, as I said, Atlas replaced the turn outs, and I do believe you are right.
Sorry it took me so long to get back to you, this is all new to me, I can do about anything with the trains, but to find where I was here, I'm lost.
mjm