high power switches and amps

Discussion in 'General Electronics Chat' started by saturatEd, Nov 12, 2008.

  1. saturatEd

    Thread Starter New Member

    Nov 12, 2008
    6
    0
    Greetings

    I'm working on something which involves high power pulse magnets (It's all on "paper" and in theory, it's academic)
    and there is a requirement to switch 1kA current pulses which are quite long (about 1ms - 5 ms).
    And there is also a requirement to use electronic tubes due to the nature of the working environment. (present gamma radiation)

    Normally a thyratron would have no trouble switching up to 20kA, but the usual pulses for thyratrons are much shorter (most ratings are defined around 3 microseconds).
    Certain cold cathode thyratrons can switch up to 200kA for as long as 0.5 miliseconds, which would most certainly do the job, but they suffer from
    long recovery time.
    And I actually need a device which would recover in a few microseconds (which is typical for regular hot thyratrons in the 10kA ballpark)

    Also, there is a requirement for high power tetrodes or triodes, which
    can pass about 10 amps in DC mode (no pulses or AC, just DC current),
    if such a thing exists.

    I don't know that much about tubes, so I'm asking someone which might know more about current world of high power tubes.

    So my question is. Does anyone know of a thyratron application where someone succesffully used a stock thyratron for pulses of about 1ms or more at 1kA (is it even possible). The pulses are flat top (square)

    And the second question is. Is there such a thing as a triode (or tetrode) which can pass around 10A constant current through anode?


    And if this is not the right forum to ask these kinds of things, does anyone have any idea which forum would be best suited for such knowledge?

    thank you
     
  2. theamber

    Active Member

    Jun 13, 2008
    318
    0
    Yes, I think why you are trying to do is possible. Current solid state electronics will not do that. Most of the people in these type of forums use solid state devices I think. Currently the only uses for tubes are in labs and in some high end audio amplifiers and broadcast stations. There are some specialized companies that build tubes you can do a google search. Or you can find some Nikola Testla forums maybe.
     
  3. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    I agree with theamber, this is very specialized knowledge. There might be a few people on here that know a thing or two about such tube-based devices, since a few have military backgrounds, broadcasting, etc.

    On a side note, I wouldn't even consider building such a thing without an expert on the topic. With these sorts of power levels, the risk is too great for anyone less an expert.

    Steve
     
  4. saturatEd

    Thread Starter New Member

    Nov 12, 2008
    6
    0
    I'm not planning to build it, I'm putting together a math model of a hypothetical system, but I want to have real components for reference (I don't want to go into science fiction, but rather use real stock components)

    But anyway, the voltage levels on this are not that high.
    At 1000 amps, the voltage on the thyratron would be about 100V, and
    on the magnet about 12V, so the risk of power shock is not greater than by handling a regular household device.
     
  5. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    I didn't say specifically shock.. Have you ever seen a short circuit happen at high power? The typical household electrical can probably produce in the neighbourgood of 6KW for a very short amount of time. What you are talking about is 100KW, or 16 X the power.

    Good luck designing your system, sorry that others weren't able to help (yet, anyways).

    Steve
     
  6. saturatEd

    Thread Starter New Member

    Nov 12, 2008
    6
    0
    Yes , if you meant things like fires, explosions etc. , yea the power is huge and could do that.

    Anyway, I've redesigned the coils , and now I've cut the current requirement down to 250A, at 0.4 ms, which is a huge improvement, and might just work with any larger stock thyratron.

    Also the mentioned triode can now be used at less than 1A, which gives me a lot more options (in fact a larger ham radio tube would probably do the job)
     
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