Turntable & Electrical connections

Discussion in 'FAQs' started by MasonJar, Jun 21, 2004.

  1. MasonJar

    MasonJar It's not rocket surgery

    Hi all,

    I have what I hope is a simple question...

    Is it possible to use the momentary contact switches that control the Atlas solenoid switch machines to power the (old) Atlas turntable? In a way that sliding the switch and holding it down will turn the turntable in the desired direction?

    What is really confusing me is how to connect three wires (green, red, black) to two posts on the turntable motor. Don't know if it is even possible...?

    Suggestions or advice appreciated. Thanks!

  2. Ray Marinaccio

    Ray Marinaccio Active Member

    Hi Andrew,
    You could use an Atlas switch machine control by using an AC transformer and a diode on each of the outer outputs of the Atlas switch machine control. The common terminal from the controller will go to one side of the motor and the two outputs from the diodes will go to the other motor terminal.
    This will give half wave rectification in either direction at the motor, so 18V AC input will give you 9V DC at the motor.

    Attached Files:

  3. MasonJar

    MasonJar It's not rocket surgery

    Thanks Ray!

    Can you be more specific about the diodes, and the "AC" coming from the power pack? Is this the AC I see on the back of my MRC Tech II? I thought the fixed DC (accessories) is what ran the tt motor?

    Thanks again from a real electrical newbie...!

  4. Ray Marinaccio

    Ray Marinaccio Active Member

    I'm not to familiar with the MRC Tech II, but most power packs have an AC accessory output that changes polarity in cycles of about 60 times a second.
    A diode can be used to let current flow in one direction only, (sort of like a check valve).
    By putting the diodes in the circuit above, you can control the direction of the motor by letting half of the AC flow through the circuit by the position of the switch.

    An electronics Wizzard I'm not. Hope this didn't make things more confusing.

    A simpler way to control a turntable may be to use a cheepo trainset powerpack and wire its track terminals to the turntable motor.
  5. 60103

    60103 Pooh Bah

    Andrew: This is a fancy way of using a single pole switch to do a reverse. If you don't use it constantly, the motor should survive.
    The common way would be to wire it to the DC terminals and use a DPDT switch (or the one on the pack) to set direction.
  6. Pitchwife

    Pitchwife Dreamer

    Hi Andrew
    The easiest way to do what you are talking about is to follow this simplified diagram. Make sure your DC power supply is strong enough to run the motor. When you push the swwitch one way the TT goes CW. When you push the switch the other way it goes CCW. When you let off, the motor stops. I bought some switches just like what you need from All Electronics but you should find them at most electronic supply houses.

    Attached Files:

  7. cidchase

    cidchase Active Member

    Hi Andrew,
    You can do it either way :cool:

    If you want to use the Atlas controller, Ray's diagram is right on!
    Use 1N4001 diodes, I guess Rad Shack has 'em. :) :) :)

    I can't speak to the speed of rotation, chances are it really rips at 12VDC.
    I'd bet that the half-wave 9V is just about right, please let us know.

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