[Elecraft] KPA500 - Advantage of min fan speed?

[Bob McGraw K4TAX]

For SSB voice operation and CW operation I leave the fan speed at 
NORMAL.   For digital modes, which all have a higher duty cycle, I 
usually set the fan speed to 1.   I do find the fan speed increments up 
and down as needed and as driven by the temperature.   When running 400 
to 500 watts most of the time for digital modes, I occasionally see 60 
degrees.   The fan speed at 1 does not elevate the room noise at all.   
In fact, I don't hear it, although I do have sound damping material on 
the wall immediately behind the equipment.   Usually something in the 
house or shack is making more noise.

As to if setting the fan speed to 1 for digital modes, it seems to keep 
the amp temperatures overall a bit lower.  No scientific study conducted.

73

Bob, K4TAX

On 10/1/2019 11:51 AM, Andy Durbin wrote:
> Thanks to everyone who contributed their experience of operating with min fan speed set above 0.
>
> I have some ideas for a test series and I'll share anything I learn from it.
>
> Here is a teaser for those interested in KPA500 thermal management.  Did you know that, for a KPA500 that has not transmitted for a long time, the Z bracket is hotter than the heat sink and the heat sink is hotter than the finals.  For that condition the heat flow is from the Z bracket, into the heat sink, and then it heats the finals.  The heat flow reversed during TX as the finals heat up.
>
> 73,
> Andy, k3wyc
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