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Ultimate power supply/ freq. gen

  1. Nov 14, 2012 #1

    taylaron

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    Greetings.
    I'm working on an experiment that needs a power supply/ frequency generator with some unique capabilities. I need to be able to vary the waveform (preferably with a computer) and vary the output voltage simultaneously. Frequencies vary from 1hz to 100khz and voltages range from 120v to 10kv. the device should have a 1kw output capacity with variable current limiter.

    I realize that this would be an extremely dangerous machine at certain settings...

    Is there any reasonable hope of being able to make or purchase such a device? If yes, how should I approach making one? Or would it be easier and cheaper to put an elephant on mars?
    I'm working on a degree in EE.
     
  2. jcsd
  3. Nov 14, 2012 #2

    NascentOxygen

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    ... means what, exactly? It's a sinewave generator, and you want the computer to just control the frequency (and amplitude)? Or it's a waveform synthesizer and you want to devise fancy sawtooth and complex step waveforms?
     
  4. Nov 14, 2012 #3

    f95toli

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    It sound like you could probably use a DSS followed by a HV amplifier.
    I believe you could buy what you need, but expect to pay some rather serious amount of money for it. What is your budget?
    H&S is also an issue so there might a be bunch of rules you have to follow before you can operate it.
     
  5. Nov 16, 2012 #4

    taylaron

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    Yes, I want to make "fancy" sawtooth waveforms and other waveforms.


    What does DSS stand for?
     
  6. Nov 16, 2012 #5
    What do you know of safety precautions for working around 10kv? For instance, how far must you keep conductors from other conductors at 10 kv. How will you detect arcing and shut down the generator down under an arcing condition?

    I once worked with an RF oscillator that operated at 5 kv and 1 amp. That was a surprisingly complex circuit with all the safety interlocks other circuits to keep it operating in a fail safe mode. I strongly urge you to find someone who knows HV to help you avoid dangerous situations.
     
  7. Nov 17, 2012 #6

    davenn

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    I dunno either, maybe a typo ?
    I suspect he really meant DDS -- Direct Digital Synthesis

    Dave
     
  8. Nov 17, 2012 #7
    Feasible for sure, and easier than the elephant on Mars. But really difficult.

    A first stone in the garden is the lack of semiconductors for 10kV. Putting them in series at 100kHz would be very difficult, and you're unlikely to find descriptions. Workarounds:

    - Use vacuum valves. It the output must push and pull, you need a driver floating at 10kV for the high side valve. The valves can cascode MOS is this brings anything.

    - Have an output transformer after the semiconductors. This transformer for waveforms over two frequency magnitudes is very difficult, more so at 10kV. You may have to operate in oil.

    - Maybe you can switch the output transformer for voltage range.

    - Even at favourable voltage thanks to a transformer, 1kW at 100kHz with precise forms is difficult.
     
  9. Nov 17, 2012 #8

    f95toli

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    Indeed, it was a typo:redface:. Essentially I just meant a stanard off-the-shelf DDS from e.g. Agilent or Tektronix. The waveform is the easy (aqnd cheap) part, it is the amplifier that us tricky (and very expensive)

    But again, what is your budget? And do you have access to a proper lab?
    I am pretty sure we (well, some of my collegues) could do this where I work, but the equipment is seriously expensive and all experiments of this nature are done in access-controller labs with interlocks.
     
  10. Nov 17, 2012 #9

    sophiecentaur

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    It would be much more practical to use a range of narrow-band signal / power sources. You would be paying a massive premium to have 'sweepability' when serious power at 'spot frequencies' would be quite achievable.
    But CAUTION is essential at these power levels. We don't want to be left with just a pair of 'smouldering boots' - as in comedy films.
     
  11. Nov 17, 2012 #10
    This is a difficult one. I would contact Instruments For Industry (IFI). They've supplied some rather extreme amplifiers for some of my testing.
    Though I suspect that no one amplifier configuration will meet your needs. You'll likely have to add a transformer to get to the higher voltages.

    Best of Luck,

    Mike
     
  12. Nov 17, 2012 #11

    NascentOxygen

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    I suspect OP is researching teletransportation, so your scenario may be precisely what he's hoping to achieve. :wink:
     
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