Re: DRSSTC thoughts...

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "robert heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

Jim: having worked with distilled water and ultra pure distilled water I do
NOT recomend its use for anything other than chemistry. It will carrode
anything but pure Nichel pipe. Even 304 and 316 stainless will disolve in
it. Only water with lime added is non carosive. Yes trace lime is added to
distilled water to stabelize it. I use liquid cooling with high voltage, but
I use mineral oil in my cooling electrodes and cool the oil with water or
air. This works, but water direct is a poor choise with high voltage. It
simply will Not stay pure for very long, Even glass disolves slowly.
       Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Wed, 29 Sep 2004 19:59:04 -0600
 > To: tesla-at-pupman-dot-com
 > Subject: Re: DRSSTC thoughts...
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Wed, 29 Sep 2004 20:04:45 -0600
 >
 > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 >> I don't know who started the DI water is a good thing years ago but I do
 >> wish they would go away.
 >
 > The ARRL Amateur Radio Handbook, probably.  Either there, or in some other
 > ARRL book, there's a whole discussion of watercooling (retrofit) a glass
 > envelope RF power tube, probably at 3kV anode voltage.  The original person
 > probably used distilled water, and somewhere along the line, I'd guess that
 > the wording got changed to DI (hey, it's a better insulator.. it must be
 > better, right?)
 >
 > While ARRL does have lots of practical data, the accuracy and vetting of
 > little technical details (like DI vs other water) is probably not what one
 > would expect.  I had some back and forth with the editors about an article
 > published in QST for a 700V plate supply to replace a venerable tube based
 > supply and the picture showed a DMM connected with the tiny Radio Shack
 > style clipleads tangled with the power cord, etc.  And, there were some
 > component rating and design safety issues.   Not that it can't be done
 > safely, it's just that the pictures shouldn't encourage bad practices.  The
 > author of the article responded directly to me, and made some assertions
 > which, while I hesitate to call them outright lies, would be tough to
 > validate (i.e. he claimed the wires in the photo were HV clipleads... which
 > made me wonder if he had ever seen real HV wire).  I can fairly confidently
 > assert that the author had no HV design experience (where HV is defined as
 >> 100V) based on his component selection and layout.  What makes it worse is
 > that he's selling kits.
 >
 >
 > I run into this issue almost every day in tech
 >> support. DI may have it's place but not when your metal is going to be
 > eaten
 >> away in critical places!
 >> Mike
 >>
 >> ----- Original Message -----
 >> From: "Tesla list" <tesla-at-pupman-dot-com>
 >> To: <tesla-at-pupman-dot-com>
 >> Sent: Wednesday, September 29, 2004 12:20 AM
 >> Subject: Re: DRSSTC thoughts...
 >>
 >>
 >>> Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >>>
 >>> Hi,
 >>>
 >>> "DI" water trends to "tear up" things...  We have a 60KW generator here
 >>> that can waist 30kW into the dirty cooling water as a pure resistive
 >>> VI...   Water cooling "can be" like 100X better!!!  But be very careful
 > of
 >>> having voltages across that water barrier...  We have giant IGBTs with
 >>> water directly on their backs, but thermal studies suggest we need
 > copper
 >>> heat spreaders instead for max dissipation...  Big tubing lengths are
 >>> legendary for fighting this... but that gets silly after a point....
 >>>
 >>> Cheers,
 >>>
 >>> Terry
 >>>
 >>>
 >>>
 >>> At 10:05 PM 9/28/2004, you wrote:
 >>>> Hi Terry, Steve and everyone,
 >>>> About the cooling issues, especially the die's, and whole devices,
 > I
 >> like
 >>>> water cooling. Distilled water of course and non-conductive hose, ~1
 > foot
 >>>> per kV in length and then some safety factor. At work we routinely use
 > it
 >>>> cooling the big triodes of induction heaters of 600 kW output class
 > and
 >> also
 >>>> for the "hockey puck" large SCR's controlling the 480 volt 3 phase to
 > the
 >>>> transformer primary. Leakage to ground is not a problem with good
 > water,
 >> msnip....
 >>
 >>
 >
 >