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Thread: Oops

  1. #1
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    Default Oops

    Not lasers, but lots of fun in a different and scary kind of way.

    I am currently working as a test & commissioning engineer for a company that makes RF induction furnaces. The power supplies for these things are quite scary. We take lots of 3 phase, rectify it into DC, pass it through a big choke and a bank of thyristors and end up with 800V DC @300A, which is switched at about 10KHz, passed through a big coil and makes things very hot. To keep things in check, the power electrics, choke and bus bars are water cooled at 5 bar pressure. It kind of reminds me of playing with big argon power supplies and brings back happy memories.

    Anyway, we have been playing with an experimental design and have run into a couple of hiccups along the way. During the latest test, we trashed the bottom plate of the furnace and managed to weld a 12mm thick, 200mm diameter graphite tube to stainless steel. That plate is an inch and a half thick billet of 310 stainless. Its also warped and about 3mm at the edges.


  2. #2
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    Quote Originally Posted by QUAZAR View Post
    end up with 800V DC @300A <snip>
    It kind of reminds me of playing with big argon power supplies
    Don't know what kind of monster argon supply you were working on that had 300 amps of tube current!

    Seriously though, inductive heating is fun. I always enjoyed this short clip demonstrating the concept:



    ( http://i.imgur.com/W1HldKR.gif )

    Adam

  3. #3
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    Default

    The argons were only 60A, but the power supply theory was similar.

  4. #4
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    Just yankin' your chain pal. But yeah, line-rectified DC at 300 amps would be pretty cool to play with. (Just watch where you poke your fingers, right?)

    Ever figure out why your cooling solution failed on that last run?

    Adam

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