[Elecraft] KPA500 - Advantage of min fan speed?

[Fred Jensen]

When running RTTY with the KPA500 I no longer have, I noticed that, with 
a minimum fan speed greater than zero, the temp tended to fall lower 
during RX periods than when the min speed was zero. During the 
subsequent TX period, having started from a lower temp, it would not 
rise as high, keeping the fan speed one step lower by the end of the TX 
period.  I assume this was because there is significant thermal 
"inertia" in the amplifier but thermodynamics was never my best 
subject.  RTTY operation tends to have a regular-ish pattern of on-off, 
I never noticed the fan going to high on CW.  I suppose the FT modes 
would present an even more regular pattern.

All anecdotal Andy, I didn't bother to take any data.

73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County

On 9/29/2019 7:38 PM, Andy Durbin wrote:
> The KPA500 offers a minimum fan speed setting which is settable by menu or serial command.  Some posters have advocated setting a minimum fan speed higher than zero, presumably thinking it offers some advantage in thermal management.
>
> Does anyone have any hard data that shows that the KPA500 runs cooler, or with lower peak fan speed, when minimum fan speed is set above zero.
>
> Running a rigorous test may not be easy since it would seem to require the same ambient temperature, same finals starting temperature, same TX periods, and same antenna system load.
>
> I'm curious because, before CQ-WW-RTTY I configured my KPA500 to set min fan speed to 1 at start of TX and reset min speed to zero 30 seconds after stop of TX.  Of course the fans ran faster than min speed during TX but I don't have any feel for whether the higher speeds were any more protracted than before the min speed change.
>
> Please share you experience of using min fan speed greater than zero, and any data if you have it.
>
> 73,
> Andy, k3wyc
>