Reduce transducer power for ultrasonic bath?

Discussion in 'The Projects Forum' started by smilem, Nov 13, 2013.

  1. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Hello, I would like to reduce transducer power for ultrasonic bath.

    1. I could use analog simple wirewound pot I think.
    I would have to measure amps, volts, then see what power pot I need. This would allow to pass the 25Khz signal to transducer unaltered right?

    2. I could use some sort of fancy electronic control with nice display for volts, but what?

    If they would hold the power needed would the controls like this work:

    http://www.ebay.com/itm/Adjustable-...al_Components_Supplies_ET&hash=item1e82527f23

    http://www.ebay.com/itm/NEW-5V-30V-...923?pt=LH_DefaultDomain_0&hash=item19e08df07b

    Would I still get the 42Khz output to the transducer?

    The model is Proclean 507.

    I want to make something like this:
    http://ecx.images-amazon.com/images/I/71YmvtL6nnL._SL1000_.jpg
     
    Last edited: Nov 13, 2013
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    745
    No, you need to alter the amplitude of the 40Khz signal to the transducer, so you need to open up your device and see how its connected on the circuit, take pictures and upload them

    NOTE THE FOLLOWING CIRCUIT USES LIVE MAINS CHASSIS

    here is a circuit of one that has been modified, it uses a transducer that is fed from a push pull transistor pair, your circuit may be different, it may be fed from a transformer output type.
     
    Last edited: Nov 13, 2013
  3. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Here are the photos, what a shocker they (ulsonix) assembled it very dangerously.

    Should I clean the flux even more?

    Photo01, very dirty PCB.
    http://i.imgur.com/nme7BXL.jpg

    Photo02, dangerous assembly
    http://i.imgur.com/9MnLxCo.jpg

    Photo03, Back of PCB
    http://i.imgur.com/l4d3kL5.jpg

    Photo04-09 PCB (should I clean it even better?)
    http://i.imgur.com/QTwWi7z.jpg
    http://i.imgur.com/5oeXFLL.jpg
    http://i.imgur.com/63sY48P.jpg
    http://i.imgur.com/NiQuyXE.jpg
    http://i.imgur.com/hPgr3YS.jpg
    http://i.imgur.com/Fb5gyLE.jpg

    I added insulation to the bottom
    http://i.imgur.com/wik2cqm.jpg
     
  4. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    Looks like your circuit is also a live chassis driven direct from the mains, using the two transformers, you need to trace the circuit out from the speaker/transducer back to the circuit board.
     
  5. smilem

    Thread Starter Active Member

    Jul 23, 2008
    132
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    Could you be more specific?
    As somebody else said:

    "If the oscillator is operating independently from the transducer and driving an amplifier that powers the crystal then you can use a wire wound resistor (POT) to control the power that gets to the transducer"

    I don't see any crystal on the board that transducer is connected to. So the signal must come from the "very complicated" - second board on the side (see photos). I already have a wire wound POT just need to make sure wattage, perhaps I should give it a try?
     
    Last edited: Nov 27, 2013
  6. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    You need to re engineer the circuit by drawing it out, follow the circuit back from the sounder to the pcb , it looks like it goes to the transformers and probably driven by the power transistors,

    so you could reduce the signal by reducing the supply to the transformer or transistors, but you need to draw the circuit to find which method to modify it.
     
  7. smilem

    Thread Starter Active Member

    Jul 23, 2008
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    Would a component trace on transparent sheet (both sides) and scanned work? Redrawing everything into schematic is very hard (at least for me.)
     
  8. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    I would start by following the mains supply coming in and see if it goes to a transformer to provide the dc, if that's so then you can alter it at the sounder output, if its a mains chassis, ie NO ISOLATION then your dealing with high voltages around 200V, so it gets dangerous.


    Looking at the image *Y48P.jpg, i can see two opto-couplers(white 6 pin devices), which leads me to think its a live chassis on the sounder side, so it may look similar to this circuit which has a self oscillating circuit around Q1/T1 top right and corner, so the only way to alter the volume is to reduce the output to the sounder on the secondary side of T1.

    But until you draw the output side we wont know.
     
    Last edited: Nov 28, 2013
  9. smilem

    Thread Starter Active Member

    Jul 23, 2008
    132
    0
    Thank you for your help.

    Transducer has 2 wires labeled + and -
    So I doubt it's got 220V live mains going to transducer.

    I'll have to measure voltage with my DMM, I think I need to measure the current and frequency right?
     
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