[Elecraft] Upper limits of KPA500?

[Dave Cole]

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."