Wiring for CAB control with AC Power

Discussion in 'FAQs' started by TR-Flyer, Jan 24, 2002.

  1. TR-Flyer

    TR-Flyer Member

    I have four S-Gauge modules that are a part of a club layout. The modules contain two main lines run off the club transformers. I have added a pair of turnouts on the inner main line that connect to a pair of sidings with a spur. I want to set up the sidings so i can use CAB control, allowing either a transformer located at the siding modules, or the club tranformer located somewhere else on the layout, to operate trains on the sidings.

    Here's my question. Can i use single pole double throw center off switches on my control panel, in lieu of DPDT switches, and keep the "common" wire, connected throughout the sidings? If so, do i connect the club common and the siding commons together?

    Doing this would save a lot of wire and some complexity. I have read the archive material, and anything else i could get my hands on, but haven't found a discussion of this when your system is AC based.
    Thanks for any and all help.
  2. billk

    billk Active Member

    Ted -
    AC, huh? Wow, I didn't know that. How do you reverse direction?

    Anyway, using a SPDT sounds OK if you are able to hook the commons together. Does your club layout have more than one transformer now, and are their commons connected?
    - Bill
  3. TR-Flyer

    TR-Flyer Member

    Hi Bill:
    Yup, AC it is. You get reverse by using a sequencer housed in the tender or engine. The sequencers are either four step; forward, stop, reverse, stop; or two step; forward, reverse. You sequence the unit by cutting the current on and off, each on/off cycles the unit through one step in the sequence. The four step units require a lot of toggling when you're working a yard, but they allow you to have the lights on when the engine is just sitting still. Gilbert made some DC units also but i don't have any of those.

    ANYWAY...., the club uses a seperate transformer for each loop and they are not connected together. I think all i'd have to do is "phase" my tranformer with the one running the inner loop. My understanding is you do this by checking for any sparking at the engine's wheels as they roll over the insulated rail gap between the two CABs. If it sparks you reverse the wall plug on one transformer to get both aligned on positive and neutral lines coming off the house current.

    How's this sound?

  4. billk

    billk Active Member

    Ted - And the answer is:
    a) Yes
    b) No
    c) I don't know
    d) Could you repeat the question?

    Actually, it does sound OK. Just don't blame me for the blue smoke!

    Are the club transformers either home-brew or kinda old? I think almost all 115vac plugs and receptacles are polarized anymore, either via the grounding prong or by having one of the blades a little wider than the other.
  5. TR-Flyer

    TR-Flyer Member

    I thought the blue smoke was SUPPOSED to be there!

    Most of our stuff was made between WWII and '67 when AC Gilbert bellied up. To us, polarized means:
    1. You've got some REALLY expensive sun glasses.
    2. The group can't decide whether it should be Kennedy or Nixson.
    3. You were a crew member on the Nautilus.

    So we have to test to see if our transformers are in sync. (And maybe we should look into that blue smoke thing too)

    I'll drop a note to one of our club guys and see what he thinks about this. Thanks for your help.

  6. kf4jqd

    kf4jqd Active Member



    I had a AC course when I went to the local tech school. You can run 2 different transformers, but the lines must be insulated. If you run one transformer and the other is shut off. You have control of the train on the entire layout. If you operate two at the sametime, here whats going to happen. You can start a fire or worst. Damage those expensive S-gauge trains!!!:eek:

    The ONLY way to do this is: Add a remote switch to turn off the other transformer! Have the switch setup so that when you turn one on the other is turned off. This is the same principle in you house wiring.

    You have one light but you want 2 switches to control it. I hope this helps!

  7. TR-Flyer

    TR-Flyer Member

    Thanks for the input Andy:

    I've been reading a lot the last couple of days and it looks like you can set up these AC transormers using a common neutral and then just switch the variable voltage side using SPDT-CO toggles on the control board. The thing you have to do is phase the transformers. A friend found several articles in S-Gaugian that covered how you do this task. And since it involves sparks it has the same attraction as the rest of the ACG stuff.

    Will post the results later this week. Straightening out the module benchwork today. The ply tops warped, i think due to the glue used to apply the carpet to them. Also having trouble with the quality of the 1x 4s used to frame it out.

    Work keeps interfering with my hobby.


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