[Elecraft] Upper limits of KPA500?

[kc8wh.mh]

I use my KPA 500 in SSB and CW ops. Much of it as net control on traffic nets and passing traffic. A little pile up breaking during DXing and some hunt and pounce contesting.Temps usually hover around 50c with some trips to mid to upper 50s.I don't remember seeing it hit 60c.In almost four years of daily use.Mike. KC8WHSent from my Verizon, Samsung Galaxy Tablet
-------- Original message --------From: Dave Cole <dave at nk7z.net> Date: 5/3/20  6:51 PM  (GMT-05:00) To: elecraft at mailman.qth.net Subject: Re: [Elecraft] Upper limits of KPA500? I hope others chime in with the operating temps they routinely see... This is a very useful discussion.73, and thanks,Dave (NK7Z)https://www.nk7z.netARRL Volunteer ExaminerARRL Technical SpecialistARRL Asst. Director, NW Division, Technical ResourcesOn 5/3/20 3:47 PM, Ted Edwards W3TB wrote:> I am glad to see these numbers and comments, because I have wondered > about the temperatures.  If running on CW in contests, it shows upper > 50s and reaches 60C.> > Thanks gang!> > On Sun, May 3, 2020 at 17:42 Dave Cole <dave at nk7z.net > <mailto:dave at nk7z.net>> wrote:> >     Pure paranoia!  :)> >     I tend to creep into things I consider limits, and not race to them.  I>     normally run the amp in such a way that it never exceeds 60 or at worst>     65 C.  Seeing it hit 70 makes me nervous...> >     So...> >     Prior to any excursions in to the above 70C area I need to learn more,>     which is what your post just helped me do!  Thank you!!> >     Knowing that others can run the KPA500 90C, eases my fear of amp final>     damage.> >     I have always ran tube amps in the past, and at one point owned a very>     sensitive SS amp, which killed a few sets of finals.> >     It turns out there were other issues at play, (design issues I think),>     but that experience made me very jumpy about SS amps.  I almost went>     back to tube amps prior to purchasing the KPA500.  After owning KPA500>     for a while now, I would never go back to tubes...  So I am being as>     careful as possible to insure I understand what I am asking the amp to>     do, before I ask it to do something it was not designed for.> >     73, and thanks,>     Dave (NK7Z)>     https://www.nk7z.net>     ARRL Volunteer Examiner>     ARRL Technical Specialist>     ARRL Asst. Director, NW Division, Technical Resources> >     On 5/3/20 1:36 PM, Jack Brindle wrote:>      > Dave;>      >>      > The KPA500 will protect itself above 90C, but it will work quite>     well at 70C. Why do you stop at 70C?>      >>      > 73!>      > Jack, W6FB>      >>      >>      >> On May 3, 2020, at 1:26 PM, Dave Cole <dave at nk7z.net>     <mailto:dave at nk7z.net>> wrote:>      >>>      >> Hello,>      >>>      >> I just got the new MMSSTV software, and will be running a bit of>     SSTV. SSTV is 100% duty cycle.>      >>>      >> Initial testing here indicates no power level is safe...  At 150>     watts the KPA500 reaches 70C pretty fast, in under two minutes, and>     70C is my upper limit for testing...  At 500 watts it reaches 70C in>     about the same time...>      >>>      >> Can I assume the amp is not the most efficient thing in the>     world at 200 watts?>      >>>      >> If the KPA500 can't deal with 100% duty cycle, for two minutes,>     how does the K3 deal with 100 watts for two minutes, at 100% duty cycle?>      >>>      >> -->      >> 73, and thanks,>      >> Dave (NK7Z)>      >> https://www.nk7z.net>      >> ARRL Volunteer Examiner>      >> ARRL Technical Specialist>      >> ARRL Asst. Director, NW Division, Technical Resources>      >> ______________________________________________________________>      >> Elecraft mailing list>      >> Home: http://mailman.qth.net/mailman/listinfo/elecraft>      >> Help: http://mailman.qth.net/mmfaq.htm>      >> Post: mailto:Elecraft at mailman.qth.net>     <mailto:Elecraft at mailman.qth.net>>      >>>      >> This list hosted by: http://www.qsl.net>      >> Please help support this email list: http://www.qsl.net/donate.html>      >> Message delivered to jackbrindle at me.com <mailto:jackbrindle at me.com>>      >>     ______________________________________________________________>     Elecraft mailing list>     Home: http://mailman.qth.net/mailman/listinfo/elecraft>     Help: http://mailman.qth.net/mmfaq.htm>     Post: mailto:Elecraft at mailman.qth.net <mailto:Elecraft at mailman.qth.net>> >     This list hosted by: http://www.qsl.net>     Please help support this email list: http://www.qsl.net/donate.html>     Message delivered to w3tb.ted at gmail.com <mailto:w3tb.ted at gmail.com>> > -- > 73 de Ted Edwards, W3TB and GØPWW> > and thinking about operating CW:> "Do today what others won't,> so you can do tomorrow what others can't."______________________________________________________________Elecraft mailing listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:Elecraft at mailman.qth.netThis list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.htmlMessage delivered to kc8wh.mh at gmail.com