[Elecraft] KPA1500 fan on stby

[Eric Swartz - WA6HHQ, Elecraft]

The PS fans run at a constant slow speed to primarily cool the main 50V 
switching PS. Interestingly, even at idle, a switcher is a little less efficient 
than at full load, so it still needs some cooling air flow.

We design all of our product cooling on a very conservative basis. There is a 
chance we over did this and can slow down the the 1500's PS fans a bit - I'll 
report back here after we do some further temperature testing.

I don't understand the comment about the PS fans getting quieter when the supply 
is under load in TX. They always run at the same speed. Is there something else 
I'm missing?

73,
Eric
/elecraft.com/

On 11/9/2018 2:52 PM, Richard Thorne wrote:
> As soon as the supply has a load on it a good bit of the noise is reduced.
>
> Maybe there's a way to put a small constant load on the supply?
>
> Rich - N5ZC
>
> On 11/8/2018 6:59 AM, eric norris via Elecraft wrote:
>> Why is the KPA1500 PS fan making so much noise when the amp is in STBY and 
>> just the ATU is being used? What are those big boys cooling?
>> I'd hoped this would change with the new firmware but it did not.  Any hope 
>> for the future?
>> 73 Eric WD6DBM
>>
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