[Elecraft] Upper limits of KPA500?

[Chuck Chandler]

Normally high 50's to low 60's in a rag chew.  During a CW contest running
stations, it sits around 65C more or less.

On Sun, May 3, 2020 at 5:53 PM Dave Cole <dave at nk7z.net> wrote:

> 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.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist
> ARRL Asst. Director, NW Division, Technical Resources
>
> On 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
> >      >> ______________________________________________________________
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> >
> > --
> > 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."
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-- 
73 de Chuck, WS1L

chandlerusm at gmail.com