The fans that cool the K3's 100-watt amplifier are thermostatically controlled.
All thermostats have a temperature spread so that they do not cycle on and off
constantly; for example, a thermostat might be set to turn on a cooling fan at
38 and off at 35.
I would like to suggest that
The fan speeds are designed to minimize heat-related stress to the
transistors. Personally I like not having to worry whether I have
toasted my final transistors because I may have inadvertently changed
some option for designer fan noise levels.
Transmitting transistors are finicky, do NOT
There are indeed two ways to eliminate fan cycling. K2AV suggests one
approach, to run the fans all the time. Another approach is to run
QRP all the time. Neither of those extremities appeals to me.
The K3 necessarily has a temperature spread (which seems to be small)
between fan-on and
The connector of concern was fixed long ago and applied to units up to #800
or so from memory...others will correct me...:-)
The K3 is used extensively in contest, DXpeditions as well as daily for for
long periods by many of us and to honest I rarely notice the K3 fans are on
and cycling has
As I understand it, the K3's final transistors are quite robust with
regard to temperature.
The transistors are robust temperature-wise because they are so
heavily heat-sinked and heavily fanned, and the fans dig in quickly to
hold the line with small temp differences. Off the heat sink those
I don't get why it needs to generate any papers or studies or anything.
Its a really easy experiment to do. Transmit into a known load and plot
temperature rise vs time. Do it under the same conditions and better
yet do each experiment several times and average results. Then all you
have to do
I don't get why it needs to generate any papers or studies
or anything.
Its a really easy experiment to do. Transmit into a known
load and plot
temperature rise vs time. Do it under the same conditions
and better
yet do each experiment several times and average results.
Then all you
have to
I suspect, like any good engineering team, they did it during design. I'd be
really surprised if they just did it to verify if their design was any good :-)
Grant/NQ5T
On Apr 6, 2010, at 4:35 AM, Brett Howard wrote:
I don
yet do each experiment several times and average results. Then all
Cooling of the amp aside, blowing 60C air from the amp into the other
components (off and on) doesn't seem like what one would want to do!
73 de Brian/K3KO
Tom W8JI wrote:
I don't get why it needs to generate any papers or studies
or anything.
Its a really easy experiment to do. Transmit
- Original Message -
From: K6LE k...@mac.com
To: Elecraft Elecraft elecraft@mailman.qth.net
Sent: Monday, April 05, 2010 11:40 PM
Subject: Re: [Elecraft] K3 Cooling
On 4/5/2010, at 9:11 , Guy Olinger K2AV wrote:
Snip
As to how good the cooling is, just to see what happened, I let
I dislike fan noise in my shack, one of the many reasons I love my iMac, and
before I considered a K3 I made a trip to Aptos and they were kind enough to
let me play with one for a bit including running the fans through their paces.
Then, and now on my own K3, I find it nearly impossible to
There was some serious engineering going on there. It would have been
SO easy to save some money and cut down on the fin size, and leave the
cabinet room for something else. It's clear that the temperature
performance was a priority in the design.
73, Guy.
On Tue, Apr 6, 2010 at 10:43 AM, Rick
Ding! This thread has hit the list daily posting limit threshold for a
single topic. ;-)
Let's end this thread. If you wish to discuss the general topic of
cooling and direction of fan air flow, please take it to direct email.
73, Eric WA6HHQ
Elecraft list moderator.
P.S. The cooling on the
This seems to be another one of those extremely variable things about
the K3. Some folk's rigs seem to be extremely quiet and others not so
much. The fans in my K3 are clearly audible at all speeds. At the
highest speed it competes well with the old tower PC I use for digital
modes.
I've seen this thread on every ham list I've read - goes on forever.
I always wonder - how does the K3 know which are the intake holes in the
cabinet and which are exhaust? The cool air comes in replacing the hot air,
right? ;-)
On tube transceivers, the finals may be oriented at the rear of
Don,
In my fluid mechanics labs it became apparent that exhaust cooling is
much more effective than forced cooling for situations that are similar
to the K3 PA 'cage'.
First is that the exhaust fan does not add to the temperature of the
air, and second, the flow can be more easily controlled.
Don (FPR type),
Do you really think it matters in K3 - with micro fan motors and such a simple
cage?
If a K3 is setup to run TX RTTY in a controlled environment,
and then repeat the test with the fan direction reversed, how much
of a temperature delta would you expect?
[Elecraft] K3 Cooling
Dont mean to jump in but I'd be the difference would be significant. Air flow
into a low pressure area causes it to expand and thus cool down (similar to
the heat exchange method used in air conditioners), and the reverse for air
stuffed into a high pressure area (compresses, heats up).
Also, in
is setup to run TX RTTY in a controlled environment,
and then repeat the test with the fan direction reversed, how much
of a temperature delta would you expect?
[Elecraft] K3 Cooling
Don Wilhelm w3fpr at embarqmail.com
Mon Apr 5 15:20:41 EDT 2010
Previous message: [Elecraft] K3 Cooling
Next
Let me throw a few things into the mix.
1.) About compression and temperature. There isn't enough
pressure to make a difference. The fan in the K3 is not
running at 40 PSI, or even at 0.4 PSI. I would bet the
static pressure is less than 0.1 inches of water (.0036
PSI). It takes a pretty big
type),
Do you really think it matters in K3 - with micro fan motors and such a
simple cage?
If a K3 is setup to run TX RTTY in a controlled environment,
and then repeat the test with the fan direction reversed, how much
of a temperature delta would you expect?
[Elecraft] K3 Cooling
Don
On 4/5/2010, at 9:11 , Guy Olinger K2AV wrote:
Snip
As to how good the cooling is, just to see what happened, I let the K3
transmit at 100 watts for a half hour into a dead band.
I wish you had said In to a dummy load..
As an aside, it's amazing how many engineering papers a simple
Hi Folks,
Which way is the air flow supposed to be through the fans on the K3? Mine
blows out, pulling air in from the slots in the top above the KPA3. (My K2
blows in.) The manual doesn't seem real clear on which way to install them in
the K3.
My K3 is nearing eight months old and
They are exhaust fans, blowing air out. The manual states that the
fans must be oriented so that the manufacturer's label faces outward.
This is correct, since the convention is that the air flows in the
direction of the label on the fan.
Bob NW8L
On Sun, Apr 4, 2010 at 4:16 PM, Jim Harris
At 04:31 PM 04/04/10, you wrote: They are exhaust fans, blowing air out.
Finally, something on/in the K3 that sucks.
John
k7up
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help:
Jim,
I too wonder what the norm is for continuous RTTY use with K3. I read
somewhere on the Elecraft site about higher volume fans that either could
be bought, or could have been considered in the design and have thought
about emailing to check on those. I suppose we would pay for that with
Jim,
Your KPA100 fan *should* exhaust air just like the K3. If yours moves
air the other way, check to be certain the fan label is on the outside.
73,
Don W3FPR
Jim Harris wrote:
Hi Folks,
Which way is the air flow supposed to be through the fans on the K3? Mine
blows out, pulling air
Hi Jim,
The K3 fans are exhaust fans and are intended to pull hot air out of
the rig.
A couple years ago (June 4, 2008 if I must be precise), Eric Swartz
said this in response to someone asking if 40 - 42C was too warm:
We will let the heatsink get up to 85C before dropping the KPA3 off-
in the Colorado QSO Party Sept 4th, 2010.
73, Jim, W0EM
Date: Sun, 4 Apr 2010 17:55:54 -0500
From: k9...@socket.net
To: w...@q.com
Subject: Re: [Elecraft] K3 Cooling
On the contrary, the ASSEMBLY manual is very clear on
how they should be installed.
They should blow out . . . as stated
@mailman.qth.net
Subject: Re: [Elecraft] K3 Cooling
Jim,
Your KPA100 fan *should* exhaust air just like the K3. If yours moves
air the other way, check to be certain the fan label is on the outside.
73,
Don W3FPR
Jim Harris wrote:
Hi Folks,
Which way is the air flow supposed
Guy Olinger, K2AV wrote:
an INTERNAL reading. If 110 F is a fault temperature, then you could
destroy your K3 by leaving it out in the sun.
That's not a valid comparison. The sort of temperature that will cause
rapid damage is 150C for silicon semiconductors, something like 100C for
I believe you make my point perfectly. Folks are complaining about displayed
K3 circuit board and PA heat sink temperatures (not air temp) of 35-45 C as
if they were somehow dangerous.
While individual components can exceed a measured temp spot in a device,
good engineering practice in
Guy, K2AV, wrote:
Blown solid state finals in HF rigs have been a common complaint in said
decades-long gossip stream.
-
It would help if we could see their plates glowing red before they failed.
Many times I've set the loading on my homebrew rig finals
From: K2ZLS k2...@optonline.net
The other driving factor here, that NOBODY seems to take
seriously, is the heating effect on the computer chips and DSP
processor. They could use heat sinks, but space limitations may be a
problem. My background is computers and I know that HEAT is their
I think there are a few points that still need to be considered here
How hot are the hot spots? 10 to 20 degrees C above ambient or 50+
degrees above ambient temp. 10 to 20 degrees above ambient temp is
nothing to worry about.
The dominant heat source is the voltage regulators, adding the Sub
On Fri, 15 May 2009 02:58:42 +, Barry VK2BJ wrote:
I have already gone down the road of cutting six vertical slots in the right
hand side panel to assist with air flow.
I would sooner mount a peltier junction on the side panel. But even
sooner than that I would just crank up the A/C...
Subject: Re: [Elecraft] K3 COOLING VENTS
To: ELECRAFT@mailman.qth.net
Date: Friday, May 15, 2009, 1:22 PM
On Fri, 15 May 2009 02:58:42 +, Barry VK2BJ wrote:
I have already gone down the road of cutting six vertical slots in the right
hand side panel to assist with air flow.
I would sooner mount
] On Behalf Of K2ZLS
Sent: 14 May 2009 21:06
To: ELECRAFT@mailman.qth.net
Subject: [Elecraft] K3 COOLING VENTS
Hi,
There have been enough posts here about the temperature inside the
K3 to start me thinking. Mine also gets very WARM on the right side by
U12 and U13. You all know how
issues. We are not stressing the DSP amd FP parts nearly as much as
typical PCs do.
73,
Eric WA6HHQ
_..._
-Original Message-
From: K2ZLS k2...@optonline.net
Date: Friday, May 15, 2009 7:13 pm
Subject: [Elecraft] K3 COOLING VENTS
To: ELECRAFT@mailman.qth.net
Hi Barry,
Thank you
issues. We are not stressing the DSP amd FP parts nearly as much as
typical PCs do.
73,
Eric WA6HHQ
_..._
-Original Message-
From: K2ZLS k2...@optonline.net
Date: Friday, May 15, 2009 7:13 pm
Subject: [Elecraft] K3 COOLING VENTS
To: ELECRAFT@mailman.qth.net
On Fri, 2009-05-15 at 19:13 -0400, K2ZLS wrote:
The other driving factor here, that NOBODY seems to take
seriously, is the heating effect on the computer chips and DSP
processor. They could use heat sinks, but space limitations may be a
problem. My background is computers and I know
Hi,
There have been enough posts here about the temperature inside the
K3 to start me thinking. Mine also gets very WARM on the right side by
U12 and U13. You all know how boxed in the Front side of the K3 has
become and now we are looking at additional features being added to the
On Thu, 2009-05-14 at 17:05 -0400, K2ZLS wrote:
Hi,
There have been enough posts here about the temperature inside the
K3 to start me thinking. Mine also gets very WARM on the right side by
U12 and U13.
--snip--
I think this would be a
worthy modification at this point, if
The reason that side feels warm is because the side itself is the heat sink
for the regulators, moving the heat out of the K3 through the metal.
There's absolutely no problem with the rig feeling warm. In fact, it's good.
It keeps everything inside dry and stable.
Ron AC7AC
--- --Original
Thanks to Brendan and all the responders:
I have received several answers similar to yours regarding the heat
sink effect. But, I already knew that. The reason I'm bringing this
up is that the concern for hot spots is already there. After running
the K3 hard, try powering down, remove
I think another important point is the ambient temperature
calibration. If that is off (the K3 thinks 30c is 15c) the fans may
not come in when they should.
Dave Wilburn
NM4M
K2ZLS wrote:
Thanks to Brendan and all the responders:
I have received several answers similar to yours
...@mailman.qth.net
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of K2ZLS
Sent: 14 May 2009 21:06
To: ELECRAFT@mailman.qth.net
Subject: [Elecraft] K3 COOLING VENTS
Hi,
There have been enough posts here about the temperature inside the
K3 to start me thinking. Mine also gets very WARM on the right
I wonder what's different ... if anything ... in our K3's?
Mine's been on about 15 hours and the FP temperature
is 33C. A digital thermometer on the desk beside the
radio shows the ambient temperature is 21C.
I -do- have the 2nd receiver installed. and in operation.
I haven't transmitted other
48 matches
Mail list logo
