Tnx Paul -----Original Message----- From: W2xj <[email protected]> Sent: Thursday, July 23, 2020 5:08 PM To: [email protected] Cc: Paul Christensen <[email protected]>; [email protected] Subject: Re: [Elecraft] KPA1500 Cooling
glycol and anti freeze. Sent from my iPad > On Jul 23, 2020, at 4:49 PM, N2TK via Elecraft <[email protected]> > wrote: > > Hi Paul, > I can't remember what we used to use for closed loop cooling. I don't think > we used distilled water because it's resistance would increase over time from > picking up ions from the metal. In our case it was cooling loops in a copper > 37" electrode. I thought it was some kind of antifreeze or maybe an oil? And > also isn't distilled water quite reactive? > To many bourbons ago 😊 > N2TK, Tony > > > -----Original Message----- > From: [email protected] > <[email protected]> On Behalf Of Paul Christensen > Sent: Thursday, July 23, 2020 3:54 PM > To: [email protected] > Subject: [Elecraft] KPA1500 Cooling > >> "Until it leaks on the LDMOS devices." > > Pure water is an insulator. Leakage becomes a problem when water becomes > contaminated with conductive particles. This rarely occurs in closed loop > systems that use distilled water when non-contaminating hoses, fittings, and > heat exchangers are used. My 2KW LDMOS amp uses water cooling in such a > closed system. > > My main amplifier at home is an Alpha PA-70V. The amp uses an openly-cooled > vapor-phase system. A pint of distilled water separates 4KV of plate voltage > and chassis ground. Water is in direct contact with the plate. In time, air > particles do contaminate the water (usually in the form of algae) and the > system must be purged and refilled at annual intervals. If leakage exceeds a > predetermined amount, the amp faults and shuts down. > > Paul, W9AC > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > [email protected] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net Please help support this email > list: http://www.qsl.net/donate.html Message delivered to > [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
