Dual Speed Control Circuit

Discussion in 'Circuit Help' started by mortier, Oct 11, 2017.

  1. mortier

    mortier

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    I'm hoping to reproduce a speed control circuit. It powers a 110v AC universal vacuum cleaner motor which is installed in an old-time payer piano. The electric suction motor overcomes leaks in the old foot-pump player piano. It's designed to provide two, pre-set motor speeds; a high-speed for playing, and a low speed for rewinding the piano roll (when less suction is needed). The switch-over is controlled by a micro switch attached to the piano's rewind control. The circuit has 2 potentiometers ("play" and "rewind"). Not being an electronics tech, could anyone help me?

    Here's what I can read on the components:

    3-Prong connector (between the 2 potentiometers): BTA12 800BW, GK2AC VU, CHN 549

    Toggle Switch: 8A 125V AC

    Red capacotots (?): DME-F250V, CO-104K

    The 3 wires on the right side are labeled "NC" "NO" "C" (Normally Closed, Normally Open, Common?)

    Many Thanks!

    Phil P1020133.JPG P1020134.JPG P1020109.JPG P1020106.JPG P1020133.JPG P1020134.JPG P1020109.JPG P1020106.JPG P1020133.JPG P1020134.JPG P1020109.JPG P1020106.JPG

    P1020133.JPG
     
    mortier, Oct 11, 2017
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  2. mortier

    Tha fios agaibh

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    What do you mean by reproduce? It works fine and you want to copy it?
    If you are trying to restore unknown connections, I can't say for certain how it works without seeing entire circuit, but it looks like jack with two wires connects to power source in series with the load.

    The three wires from No, Nc, and C go to their designed switch terminals that toggles the speed (on the roll?) fast and slow.

    If you can't find more info on this board, I would disassemble it to see what's on the other side of the board.
     
    Tha fios agaibh, Oct 12, 2017
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  3. mortier

    Minder

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    If wishing to reproduce it, it seems to be a very easy circuit to reverse engineer?
    M.
     
    Minder, Oct 12, 2017
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  4. mortier

    73's de Edd

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    SIr mortier . . . .

    YES . . . . . do you want to make another like unit, or is this one being inoperative ?

    If an inoperative unit and considering the pull of that motor and no hidden fuses blown, the most likely part to fail is the BTA12 triac.
    If replicating the unit, I see all parts being available but having to make a micro variance in using 150K linear pots instead of those 160K units shown.
    Also, all of the numbering from the centrally located BLUE diode is being needed.

    73's de Edd
     
    73's de Edd, Oct 12, 2017
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  5. mortier

    mortier

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    This circuit works, but it is no longer being manufactured, so I would like to make another. I will try to read the blue diode.

    Phil
     
    mortier, Oct 12, 2017
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  6. mortier

    Alec_t

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    The blue diode is probably a diac.
     
    Alec_t, Oct 12, 2017
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  7. mortier

    mortier

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    The blue diode is marked "DB4, X449" as far as I can tell.

    The components on board are marked "R", "D", and "C" (I assume, resistor, diode, capacitor). The micro-switch which controls the circuit is an Omron D2MC-5F (photo below).

    Phil

    P1020135.JPG
     
    mortier, Oct 12, 2017
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  8. mortier

    Alec_t

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    'DB4' identifies a diac.
     
    Alec_t, Oct 12, 2017
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  9. mortier

    73's de Edd

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    That then makes all parts still available, and the probable need to get a lever style microswitch and then fabricate that piano wire portion / extension to then be soldered to the lever..
     
    73's de Edd, Oct 12, 2017
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  10. mortier

    Minder

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    The lever is available by part No. CAA1M but may be a little short, .6mm piano wire can be used to make a custom length.
    M.
     
    Minder, Oct 12, 2017
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  11. mortier

    Tha fios agaibh

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    I'd get some perf board and copy the layout of traces and components. Solid bell wire about 24 gauge works to simulate traces but obviously make thicker traces where necessary such as on Triac A1,A2 terminals.
     
    Tha fios agaibh, Oct 12, 2017
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  12. mortier

    Minder

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    One source of Vero (strip board) is here, half way down the page.
    Prototyping Boards
    You can also place .2" spaced screw terminals for power connections.
    M.
     
    Minder, Oct 12, 2017
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  13. mortier

    mortier

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    Thanks. Could someone tell me a good place to order the components? Our Radio Shack is gone.

    Phil
     
    mortier, Oct 12, 2017
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  14. mortier

    Minder

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    From Canada my goto is Digikey, but there are others such as Mouser and Jameco etc.
    M.
     
    Minder, Oct 12, 2017
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