Posted by Joe Planisky on May 13, 2009; 3:25pm URL: http://elecraft.85.s1.nabble.com/K3-KPA3-Fan-Upgrade-Question-tp2883346p2884541.html
Apparently not all K3s are created equal, thermally speaking.
On my K3, it takes about 2:45 of 20 wpm CW at 50 watts into a dummy
load to raise the PA temp from 18C to 37C (the fan turn-on temp.
Ambient temp is about 18C.)
73
--
Joe KB8AP
On May 13, 2009, at 6:24 AM, Ed Muns wrote:
> You're doing what?!
>
> For two years I've run my K3s in NAQP at 100 watts with high duty
> cycle. The fans seldom turn-on and the PA is barely warm. If you
> can out-design N6KR, I'd be amazed.
>
> Ed - W0YK
>
>
> ------Original Message------
> From: Brian Binkley
> Sender: [hidden email] > To: [hidden email] > Sent: May 13, 2009 05:11
> Subject: [Elecraft] K3 KPA3 Fan Upgrade Question
>
> Hello,
>
> I am currently in the process of upgrading the fans for the KPA3 100
> Watt
> Amplifier module because the heatsink temperature gets too high for my
> liking. I am upgrading both fans to a fan with higher CFM output.
> Last night
> I hooked both fans up to the KPAIO module to test and see if they
> will work.
> When I am on fan power level one, the fans try to but are unable to
> start
> up. I have to bump them to start them spinning. Power level two has no
> problem spinning them up. When I went to power level four and then
> brought
> the power level to one, the fans did not have any problem continuing
> running. The fan specs can be found here
> http://www.sundialmicro.com/ipcqueen_dc_fan_606010_ball_bearing_3pin_2033_1199.html > .
> Is there any components that I can add in line to provide the
> necessary
> power to start the fans up at power level one?
>
>
> Thanks
> Brian Binkley
> KD8CPF
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