I wired my Atlas UT Switch Machine to my Digitrax Zephyr using a SPDT Momentary switch. I connected the Atlas Switch Machine Common to Rail A on the Zephyr, and the other two connections to the outer poles of the SPDT. I connected the Common Pole on the SPDT to Rail B on the Zephyr. The Problem: When I close the SPDT, The Atlas Buzzes and makes a little progress but will not completely throw the acuator. {picture below} Also, I have to continue hold the SPDT closed to get the Atlas to move. I thought these machines were only supposed to require a momentary pulse. Can anyone point out problems with this ciruit, or give suggestions. Or am I just under powered? Thank you, FYI - In the future I plan to power my switches and accessories with a dedicated power supply. I just wanted to test out some devices and see if I could figure out the basic circuits before I committed to one. Also, probably going to buy a Tortoise and try it out.
I don't think anything is wrong with the UT switch. They are not to be powered by the DCC signal sent out to the rails. If you want to test the setup use AC or DC power right from the power supply you are using to run your DCC system. Also it would be best to get a separate power supply for running all accessories as you stated but your wiring diagram will work.
You should use a separate DC power source - especially when you get to installing/using the Tortoise(s). DCC track power is not really DC, not really AC - sort of a weird combination that a standard multi-meter can't ready properly... If you are using the SPDT momentary that comes with (some of) the Atlas UT switch machines, both power leads should go to one side of the SPDT, and then three leads go from the other side tot he switch machine. I stand to be corrected, but I think I've got the important parts right... Andrew
Thanks for the advice. I just hooked this circuit up to a 9V battery and the Atlas snaps like I was expecting. I guess the Zephyr is not capable of powering this switch machine. Thanks again. Greg
I intended to do my whole layout with Atlas machines. I started with five or so, and they all did the same thing you're describing. I had the same problem you did. I could NOT get them to work consistently, even after I got them properly adjusted, and even with a dedicated power supply. I gave up and bought Tortoises.
Atlas switch machines were designed to operate from the accessory output of DC power packs (Normally 16VAC). The DCC signal put out by the Zephyr is AC (sort of - it's 8KHz squarewave instead on 60 Hz sinewave), but it's only 12-13 volts, so between the lower voltage and the higher frequency, it's no surprise that the switch machine didn't respond well. You need either 12VDC or 16VAC (instead of DCC from Rail A/Rail B) using the hookup you described. If you want to use DCC to control turnouts, you would need a stationary decoder (Digitrax DS64 or one of the many others out there), which will translate a DCC command to a DC pulsed voltage for the switch machine. Most can be optioned to drive Tortii as well.
