Ultimate power supply/ freq. gen

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Discussion Overview

The discussion revolves around the feasibility and design considerations for creating or purchasing a power supply and frequency generator capable of producing variable waveforms, voltages from 120V to 10kV, and frequencies ranging from 1Hz to 100kHz. The conversation touches on safety concerns and technical challenges associated with high voltage applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants inquire about the specific requirements for varying waveforms, questioning whether the need is for simple frequency and amplitude control or for more complex waveform synthesis.
  • One suggestion involves using Direct Digital Synthesis (DDS) followed by a high voltage (HV) amplifier, with a note that purchasing such equipment may be costly.
  • Concerns are raised about safety precautions when working with high voltages, including the need for proper interlocks and the complexity of circuits at these levels.
  • Participants discuss the challenges of using semiconductors at 10kV, suggesting alternatives such as vacuum valves and transformers, while noting the difficulties of achieving precise waveform generation at high frequencies.
  • There is a mention of the practicality of using narrow-band signal sources instead of a single versatile generator, highlighting the potential cost implications of having a device with sweeping capabilities.
  • One participant recommends contacting a specific company for extreme amplifiers, indicating that a single amplifier solution may not suffice for the required specifications.

Areas of Agreement / Disagreement

Participants express a range of views on the feasibility and design of the power supply/frequency generator, with no consensus reached on a specific solution or approach. Safety concerns and technical challenges are acknowledged by multiple contributors.

Contextual Notes

Limitations include the complexity of high voltage applications, the need for safety measures, and the potential requirement for additional components like transformers to achieve desired voltage levels.

Who May Find This Useful

This discussion may be of interest to electrical engineering students, professionals working with high voltage systems, and individuals involved in experimental physics or engineering projects requiring specialized power supplies.

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.
 
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vary the waveform
... 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?
 
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.
 
NascentOxygen said:
... 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?

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


f95toli said:
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.

What does DSS stand for?
 
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.
 
taylaron said:
What does DSS stand for?

I don't know either, maybe a typo ?
I suspect he really meant DDS -- Direct Digital Synthesis

Dave
 
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.
 
davenn said:
I don't know either, maybe a typo ?
I suspect he really meant DDS -- Direct Digital Synthesis

Dave

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.
 
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.
 
  • #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
 
  • #11
sophiecentaur said:
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.
I suspect OP is researching teletransportation, so your scenario may be precisely what he's hoping to achieve. :wink:
 

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