Atlas switch burnouts

[LV325]

I'm stumped over how to keep my Atlas snap switches from burning out. I don't push the Atlas switch controls for more time than it takes to switch the points. I added a Miniatronics CDU between each of the switches and the 16 volt AC transformer and still they burn out leaving the transformer over heated. Any suggestions?

[wvg_ca]

probably don't have the CDU installed correctly .... the transformer shouldn't get hot, not even very warm to the touch ???

[ATSFGuy]

Are the switches on your layout operated electronically or manually?

What type of transformer are you using?

[nealknows]

Question: Do you have them hooked up to the AC terminals on the power pack/supply or DC? I would double check where you put them on the power pack. They operate only on AC momentary contact. I have over 100 Atlas switch machines on my layout. The only way they melt is when someone leans on the pushbuttons on my fascia.

Neal

[jjdamnit]

Hello all,

I have numerous Atlas #56 Switch Control Boxes on my layout powering twin-coil solenoid type Remote Switch Machines; both Atlas and PECO.

Even before converting my pike to DCC all the switch motors; no matter what the manufacturer, were powered by a separate source as opposed to the accessory terminals on the DC cabs.

To power them I bought a "wall-wart"; Miniatronics (model WT 16) Input 120 VAC 60 HZ 18 W; Output 16 VAC @ 800mA, from Amazon.

This is wired to a dual row, panel mount terminal block barrier strip. One side "+" (hot) and one side "-" neutral.

From the "+" (hot) side of the terminal block a single wire connects to a SPST toggle switch, mounted on the control panel. Two wires from the SPST switch are then connected to the "+" sides of two PECO PL-35 C.D.U.s.

I did this so I could cut the power to the C.D.U.s from the control panel without having to unplug the wall-wart.

From the terminal block two separate wires go directly to the input "-" sides of the C.D.U.s. 

(Some fine folks on these forums said two C.D.U.s was excessive. See my disclaimer/signature.)

The outputs of one C.D.U. then goes to one half of the Atlas #56 Switch Control Boxes.

Each Switch Control Box is linked to the next one via the pass through connectors on the Switch Control Boxes.

From each Switch Control Box the three control wires are connected to the individual Remote Switch Machines (#0052 or #0053).

I have several pairs of Remote Switch Machines that are activated from the same switch control box. One push throws both Remote Switch Machines simultaneously. 

For these paired turnouts a single set of three control wires from the Switch Control Box are connected to the first Remote Switch Machine.

A second set of three wires are piggy-backed on the terminals from the first Remote Switch Machine to power the second Remote Switch Machine.

I also have several PECO #2 turnouts; some single some paired.

Because of the stiffness of the springs in the points extra amperage oomph is needed to throw the paired sets of Side Mounted Turnout Motors. 

Once the C.D.U. discharges, continuing to depress the Switch Control Box button does not send more power to the Remote Switch Machine(s) or the Side Mounted Turnout Motors.

Only when the button is released on the Switch Control Box and depressed again is another pulse discharged from the C.D.U.s.

Because the pulses are momentary no damage to the twin-coil solenoid type Remote Switch Machines or Side Mounted Turnout Motors occur because the power is not continuous. 

Hope this helps.

[rrinker]

 Back when I built my last N scale layout, I was burning out the Atlas machines left and right, despite being careful to not hold the button. So I built my own CDU from Practical Electronic Projects for Model Railroaders, and never burned oout another one. That circuit is nearly identical to the commercial units, so they should work the same. Never had a problem with HO because when I built my next layout after that (long after that - after HS and college) I switched to Tortoises. But on HO layout prior to the N scale, using Atlas motors, I never had an issue - but the older ones back in those days were a lot more robust than todays (and drew a lot more current). The current HO ones looks like the N scale ones and so are probably fairly delicate, but a properly wired CDU should not allow enough current to melt them even if you deliberately hold the button down. I suggest you carefully check your wiring against the instructions to make sure the CDU is connected and operating properly.

                                           --Randy

 

[bearman]

I connected one turnout to a SPDT toggle switch (momentary on/off/momentary on) via the AC terminals of an old MRC transformer Model RL-1250.  The transformer is permanently "on", except that it is plugged into a surge protector which is switched on when I am running my layout.  So far, so good.  All my other turnouts are manually thrown.  The location of this one was a design error which produced an "OH NO!" moment when I realized it was not easily acccesible for manual operation.

[LV325]

Will check again but I followed Miniatronics' instructions which said to wire 16 volt power ac/accessories posts to input posts on CDU and then wire CDU output posts to Atlas switch controls.  I found I had to wire each switch control directly to the CDU output posts and not through a common wire from the tandem-connected switch controls for it to work.

[LV325]

Electronically.  I have used an old Life-Like 17 volt max transformer (accessory posts) and an old Backmann 17 volt max transformer (ac posts) and have had the same issue with both.

[LV325]

On both transformers I have used, I have had them connected to the AC or the "accessories" posts.

[LV325]

Roger. Thanks. Will do.

[LV325]

I actually bought some momentary on/off/momentary on toggle switches to replace the Atlas ones that I thought somehow were sticking.  However, I haven't figured out how to connect the new toggle switches to the to the Atlas switch machines.  The toggles I bought have two rows of three posts/connectors and the switch machines have three wires.  Which wires go where on the toggles?

[LV325]

Thanks for the info. Will go back and study.

[jjdamnit]

Hello all,

LV325

I'm stumped over how to keep my Atlas snap switches from burning out.
...I added a Miniatronics CDU...

From the Miniatronics web page...

"Please note this unit is not compatible with the Atlas Switching machines." [Last sentence at the bottom of the page. (Italics added for emphasis.)]

Sorry for the bad news!

As I posted the PECO PL-35 C.D.U. is Atlas friendly and can be powered by either Direct Current (DC) or Alternating Current (AC) as I have done.  

Again, sorry to be the bearer of bad news. 

Hope this helps. 

[bearman]

LV325

I actually bought some momentary on/off/momentary on toggle switches to replace the Atlas ones that I thought somehow were sticking.  However, I haven't figured out how to connect the new toggle switches to the to the Atlas switch machines.  The toggles I bought have two rows of three posts/connectors and the switch machines have three wires.  Which wires go where on the toggles?

LV325...there is a web site called "Building Your Model Railroad" with a section dedicated to "wiring a solenoid switch machine for remote turnout control".  That page has a great schematic on how to wire the switch machine.  However it is not color coded.  The middle wire on the switch machine is the black wire.

[rrinker]

jjdamnit

Hello all,

 

 

LV325

I'm stumped over how to keep my Atlas snap switches from burning out.
...I added a Miniatronics CDU...

 

 

From the Miniatronics web page...

"Please note this unit is not compatible with the Atlas Switching machines." [Last sentence at the bottom of the page. (Italics added by me.)]

Sorry for the bad news!

As I posted the PECO PL-35 C.D.U. is Atlas friendly and can be powered by either Direct Current (DC) or Alternating Current (AC) as I have done.  

Again, sorry to be the bearer of bad news. 

Hope this helps. 

 

 Wow. The image doesn;t show the entire circuit board so I can't see if there is any more to the circuit than the capacitor, diode, reistor, and transistor shown but in general a CD supply is a very simple circuit, to make one that doesn;t work with Atlas switch machines takes some doing. Especially at that price.

The Circuitron Snapper is also an option, those seem to work fine.

                                        --Randy

 

[nealknows]

LV325

I actually bought some momentary on/off/momentary on toggle switches to replace the Atlas ones that I thought somehow were sticking.  However, I haven't figured out how to connect the new toggle switches to the to the Atlas switch machines.  The toggles I bought have two rows of three posts/connectors and the switch machines have three wires.  Which wires go where on the toggles?

 

From your description, it sounds like you bought DPDT momentary toggle switches. You can use one side of the switch (unless you have a pair of crossover switches). One wire from the AC power supply goes to the CENTER of the Atlas Machine. The other goes to the MIDDLE post on the toggle switch. The remaining posts on the same side would go to each screw on the Atlas switch. This is what I do to throw my Atlas switches with momentary bush buttons. The concept with the momentary toggle switches is the same. 

I have no issues with them.

Neal

[MisterBeasley]

jjdamnit

"Please note this unit is not compatible with the Atlas Switching machines."

Wow, that's bizarre.  Given the OP's problem, the issue may be that their CDU is too powerful and is burning out the coils on Atlas machines.

I would think that 80-90% of all twin-coil machines in use are from Atlas.  Why would Miniatronics produce a machine that is not suitable for most of its target market?  Did Atlas start making them cheaper so they fry more easily?

[rrinker]

 Atlas DID start making them cheaper - the HO ones are very similar now to the N scale ones I used 30+ years ago. The HO ones used to be a lot more robust than the N scale ones. However, my CDU I built prevented any further burnouts of the N scale ones, so should keep even the new HO ones from burning out.

 Miniatronics must have made theirs for old school twin coil machines - the big beasts you rarely see any more, like Kemtron. The thing is, the circuit I built had a fairly high value resistor as a bypass, so once the cap was discharged, the amount of current that could flow through the coil even if you held down the button was minimal. The transistor would keep the capacitor from recharging if a button was held down or stuck. I see the transistor on the Miniatronics circuit, so either they left out the limiting resistor, or used a smaller value than other circuits, although why I could not guess. It doesn't really effect the ability of the capacitor to deliver a high power but short burst into the switch machine, it's mostly there to just limit the steady state current to prevent burnout.

                                  --Randy

[LV325]

Oh, it DOES help. Thanks for that critical piece of info and I'll try to get the PECO.  Interestingly, the instruction sheet I received from Miniatronics for the PDC-1 doesn't mention anything about Atlas switches but instead states "All snap-action models can be used from PECO to TENSHODO." 

I sent Miniatronics an email explaining the problem and asking for advice earlier this week but they have yet to respond.   

[jjdamnit]

Hello all,

The PECO units are readily available from retailers like Model Train Stuff.

I don't have the ability to post a schematic (I refuse to go through a 3rd party photo hosting site).

If you P.M. me I can send you a schematic of my wiring.

Good luck.

Hope this helps.

[BRAKIE]

You do know you are suppose to push and immediately remove the finger? No need to keep pushing the contol until the points throw.

[jjdamnit]

Hello all,

BRAKIE

You do know you are suppose to push and immediately remove the finger?

That's the point of having Capacitive Discharge Units.

When the control unit is pressed the C.D.U. emits a single pulse to activate the twin-coil remote switch motor(s).

No matter how long you keep the control unit depressed it only send out the single pulse and does not allow for continuous power that can damage these type of remote switch motors.

This can be a necessity when having guest(s) unfamiliar with twin-coil remote switch motors or children that just like to push buttons continuously from damaging the units.

Also, because it is a capacitor the amperage generated through the discharge pulse has the power to move two PECO Side Mounted Switch Motors simultaneously.

Before installing the C.D.U.s I could activate two Atlas Remote Switch Machines from the same control unit but not two PECO Side Mounted Switch Motors.

By using the C.D.U.s a single control unit will now activate two PECO Side Mounted Switch Motors simultaneously.

Hope this helps.

[LV325]

Yep, do know that. Don't think that's the problem.