Re: K3 KPA3 Fan Upgrade Question

Posted by Julius Fazekas n2wn on May 14, 2009; 1:36pm
URL: http://elecraft.85.s1.nabble.com/K3-KPA3-Fan-Upgrade-Question-tp2883346p2890122.html

Hi Joe,

Have you checked for a voltage drop from your power supply/source? or the APPs? This sounds unusual...

My K3 barely gets warm running RTTY at 100 watts or on 160 running 100 watts for 12 to 14 hours straight. I mention 160 as I have a higher current draw here, most likely due to less than perfect matching at the Tx antenna and proximity to the radio (is VERY close).

The only reason I know the fan is on is because I, out of curiosity, put my hand on the rig and feel a bit of air flow... My shack can get to 80 degrees before I decide I need the air on, even then the fan rarely ramps higher than one...

Much better than the KPA100 was/is in the same situation. Different setup and much smaller fan on that one.

73,
Julius

Joe Planisky wrote

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: [e-mail]
> To: [e-mail]
> 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
> [e-mail]
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