DCC Power Output

Discussion in 'DCC & Electronics' started by Freelancer, Nov 17, 2007.

  1. Freelancer

    Freelancer Member

    I am trying to wire my roundhouse and turntable and am trying to find out how much power my command station is putting out. I am currently running a Digitrax Zephyr that puts out 12.8V (is that correct?) but I am trying to figure out how many amps it is putting out.

    I have a 12 position rotary switch that I will use to select the track around the turntable but I need to find out if it will stand up to the job. It is rated at 2.5A @ 125V AC. I also have a DPDT switch that will be used to switch the polarity of the turntable, it is rated at 2A @ 250VAC and 5A @ 120VAC. Will this work?

    Also, does anyone have a diagram about how to wire the DPDT switch up to the turntable? Lastly do all DCC command stations put out the same voltage/amps? I will probably be upgrading to a Super Cheif or Empire Builder as the layout progresses and I do not want to have to rewire things.

    Thanks for your help,
  2. steamhead

    steamhead Active Member

    Hi....I've got a set up pretty much like what you describe. The command station doesn't "put out" amperage. Amperage is the amount of current drawn by the layout. If the load is higher than the amp rating, then the command station will shut down and will need to be re-set after removing whatever load caused it to shut off. (The Zephyr resets itself..). A short circuit is the prime example of an overload (almost infinite...). The Zephyr should handle 3-4 single-engine trains at the same time.
    From what you describe, I think you are attempting to power the TT motor with the command station. This can't be done since the Zephyr doesn't have accessory power output. You will need a separate power source for that. I use a cheapo power pack so I can adjust the turning speed of the TT.

    The rotary switch will handle anything you throw at it (within reason...). :mrgreen:

    Wire the DPDT switch by wiring an "X" between the four outermost posts. Then feed you power to one end of the switch, and your track power off the center two posts.
    Good luck..!!
  3. woodone

    woodone Member

    Like stated in the above post- the Zephry will not power the TT motor- per say---:cry:But you can install a decoder to the TT motor and run it (the motor) just like you would a locomotive- you can get some very good control of your TT that way-:thumb:
    Just and idea you might want to explore.
  4. 60103

    60103 Pooh Bah

    Freelancer: The power that will go through the rotary switch is what is required by the locomotive(s) sitting on that track. Older HO locos used to take a whole amp; newer ones should take 1/2 amp or less. So unless the track has 4 old Athearn diesels on it, 2.5 amps rating is enough.
    But this is avoiding one of the features of DCC, isn't it? You can wire all the tracks up permanently and just select which loco you want to run.
  5. steamhead

    steamhead Active Member

    David is correct in saying that you don't NEED to have power ON/OFF to the engine tracks. But I have several spots on the layout where I can "park" an engine and cut power to it. I don't see the benefit of having all engines "live" if they're not "working"...Also, a short can have unexpected results...like all engines taking off on their own. Don't ask me how I know....:cry:
  6. Freelancer

    Freelancer Member

    Hey guys, thanks for the clarification! You can imagine my frustration trying to explain to the guy at the electronics store what DCC is and what I am trying to accomplish. :confused: Needless to say he was probably happy when I made my purchase and left.

    Right now my turntable is manually operated and will probably stay that way for a while. So the switches are strictly for power and to change polarity. I want to be able to cut power to the tracks as I have heard that leaving powered decoders on the track will cause unnecissary wear. Also I plan on having a few sound equipped locomotives so I do not want them all to power up every time I power up the layout.

    Thanks for the explaination on how to wire the DPDT switch. I would have never figured that out and everywhere I have looked just tell you to use an auto reversing unit. That is a great idea and all, but for something so simple I think I will save the reverser for my return loop.

    Thanks again for your help. It will only be a matter of time before I am back with a new request.
  7. 60103

    60103 Pooh Bah

    A quick but silly tip on wiring DPDT switches for reversing: allow a few extra inches of wire on both sides. After you finish, try it out and mount it on the panel so it points the way you want. (faster than changing the wires over.)

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