On Saturday, March 19, 2022 at 9:30:23 AM UTC-4, jla...@highlandsniptechnology.com wrote:
> On Sat, 19 Mar 2022 04:27:44 -0700 (PDT), Lasse Langwadt Christensen
> <lang...@fonz.dk> wrote:
>
> >lørdag den 19. marts 2022 kl. 09.22.54 UTC+1 skrev Jan Panteltje:
> >> On a sunny day (Fri, 18 Mar 2022 19:23:37 -0700) it happened
> >> jla...@highlandsniptechnology.com wrote in
> >> <4afa3hlpivlfi9hq1...@4ax.com>:
> >> >
> >> >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
> >> >
> >> >This might not be as good as a gigantic machined heat sink, but it's
> >> >easier.
> >> >
> >> >The little guy will be an LM35 temperature sensor.
> >> Not sure about the air flow
> >> Is there space between the fan and the surface?
> >
> >airflow goes in through the sides of the heatsink between the fins, up through the fan and out the back
> That particular cooler intakes on three sides and blows air out the
> fourth. That's ideal for my use; the hot air will blow over the
> Phoenix connector and out the back of the box.
>
> https://www.dropbox.com/s/8ubv5if7cbnsjzn/P940-8_front.jpg?raw=1
>
> Some coolers are designed to inhale their own hot air!
> --
>
> I yam what I yam - Popeye

Nice idea, but am curious: Tradeoffs are to move more air over limited surface area or increase the surface area and move less air. Looks like the heat sink is flat, limited area surface. Limited time buffer from fan failure to destruction of the semiconductors - What is doing the over temp control - CPU or dedicated temp monitor/controller?
J

On Sat, 19 Mar 2022 12:41:57 -0700 (PDT), three_jeeps
<jjhudak@gmail.com> wrote:

>On Saturday, March 19, 2022 at 9:30:23 AM UTC-4, jla...@highlandsniptechnology.com wrote:
>> On Sat, 19 Mar 2022 04:27:44 -0700 (PDT), Lasse Langwadt Christensen
>> <lang...@fonz.dk> wrote:
>>
>> >lørdag den 19. marts 2022 kl. 09.22.54 UTC+1 skrev Jan Panteltje:
>> >> On a sunny day (Fri, 18 Mar 2022 19:23:37 -0700) it happened
>> >> jla...@highlandsniptechnology.com wrote in
>> >> <4afa3hlpivlfi9hq1...@4ax.com>:
>> >> >
>> >> >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >> >
>> >> >This might not be as good as a gigantic machined heat sink, but it's
>> >> >easier.
>> >> >
>> >> >The little guy will be an LM35 temperature sensor.
>> >> Not sure about the air flow
>> >> Is there space between the fan and the surface?
>> >
>> >airflow goes in through the sides of the heatsink between the fins, up through the fan and out the back
>> That particular cooler intakes on three sides and blows air out the
>> fourth. That's ideal for my use; the hot air will blow over the
>> Phoenix connector and out the back of the box.
>>
>> https://www.dropbox.com/s/8ubv5if7cbnsjzn/P940-8_front.jpg?raw=1
>>
>> Some coolers are designed to inhale their own hot air!
>> --
>>
>> I yam what I yam - Popeye
>
>Nice idea, but am curious: Tradeoffs are to move more air over limited surface area or increase the surface area and move less air. Looks like the heat sink is flat, limited area surface.

Thermal theories are nice, but I believe experiments.

>Limited time buffer from fan failure to destruction of the semiconductors - What is doing the over temp control - CPU or dedicated temp monitor/controller?
>J

The little thing is an LM35 temp sensor. That gives us heat sink
temperature. We'll know the fet voltages and currents, so that gives
us power.

We'll run a realtime junction temperature simulation and shut down at
some Tj, probably 150C. The sim will run in an FPGA.

--

I yam what I yam - Popeye

On Sat, 19 Mar 2022 12:23:36 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>lørdag den 19. marts 2022 kl. 20.09.24 UTC+1 skrev legg:
>> On Sat, 19 Mar 2022 10:35:10 -0700 (PDT), Lasse Langwadt Christensen
>> <lang...@fonz.dk> wrote:
>> >lørdag den 19. marts 2022 kl. 18.19.27 UTC+1 skrev legg:
>> >> On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
>> >> wrote:
>> >>
>> >> >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >>
>> >> Use the center legs to conduct, but rotate bodies to allow tabs to
>> >> face the cooling surface.
>> >
>> >the tabs are facing the cooling surface
>> >
>> The cooling surface is attached to the fan fins. The tabs should face
>> the cooling surface - not as illustrated in mock4.
>
>the tabs are facing the cooling surface, mock4 is a bottom view,
>shows the transistors mounted through a hole in the PCB
>

I cut that on our classic Bridgeport milling machine. Just ignore the
obvious goof.

--

I yam what I yam - Popeye

lørdag den 19. marts 2022 kl. 21.41.31 UTC+1 skrev jla...@highlandsniptechnology.com:
> On Sat, 19 Mar 2022 12:23:36 -0700 (PDT), Lasse Langwadt Christensen
> <lang...@fonz.dk> wrote:
>
> >lørdag den 19. marts 2022 kl. 20.09.24 UTC+1 skrev legg:
> >> On Sat, 19 Mar 2022 10:35:10 -0700 (PDT), Lasse Langwadt Christensen
> >> <lang...@fonz.dk> wrote:
> >> >lørdag den 19. marts 2022 kl. 18.19.27 UTC+1 skrev legg:
> >> >> On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
> >> >> wrote:
> >> >>
> >> >> >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
> >> >>
> >> >> Use the center legs to conduct, but rotate bodies to allow tabs to
> >> >> face the cooling surface.
> >> >
> >> >the tabs are facing the cooling surface
> >> >
> >> The cooling surface is attached to the fan fins. The tabs should face
> >> the cooling surface - not as illustrated in mock4.
> >
> >the tabs are facing the cooling surface, mock4 is a bottom view,
> >shows the transistors mounted through a hole in the PCB
> >
> I cut that on our classic Bridgeport milling machine. Just ignore the
> obvious goof.

murphys law also apply to the handles moving the table on milling machine ;)

On Sat, 19 Mar 2022 11:38:14 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>lørdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
>> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
>> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
>> > wrote:
>> >
>> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >
>> > Use the center legs to conduct, but rotate bodies to allow tabs to
>> > face the cooling surface.
>> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
>
>it's rated for 125W TPD and CPU are usually 100'C max Tj
>
>0.29 C/W with the fan at max speed
>
>https://www.dynatron.co/product-page/k199
>
>

I measured 0.24, which is pretty good in the thermal business.

The hot air will blow right out the back of the box. The main box fans
might help a little too.

I might have a lot of topside copper under the heat sink, with many
thermal vias to, well, somewhere. That would help a bit too, maybe
5-10%, use some PCB surface area in the air flow.

There are hunkier coolers around, but I don't have height for them.

--

I yam what I yam - Popeye

lørdag den 19. marts 2022 kl. 21.58.36 UTC+1 skrev jla...@highlandsniptechnology.com:
> On Sat, 19 Mar 2022 11:38:14 -0700 (PDT), Lasse Langwadt Christensen
> <lang...@fonz.dk> wrote:
>
> >lørdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
> >> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
> >> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
> >> > wrote:
> >> >
> >> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
> >> >
> >> > Use the center legs to conduct, but rotate bodies to allow tabs to
> >> > face the cooling surface.
> >> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
> >
> >it's rated for 125W TPD and CPU are usually 100'C max Tj
> >
> >0.29 C/W with the fan at max speed
> >
> >https://www.dynatron.co/product-page/k199
> >
> >
> I measured 0.24, which is pretty good in the thermal business.
>
> The hot air will blow right out the back of the box. The main box fans
> might help a little too.
>
> I might have a lot of topside copper under the heat sink, with many
> thermal vias to, well, somewhere. That would help a bit too, maybe
> 5-10%, use some PCB surface area in the air flow.
>
> There are hunkier coolers around, but I don't have height for them.

you could also skip the hole and put the transistors with the tap side
up on the top of the pcb, so the whole sandwich is: heatsink, transistors,pcb
and on the back of the pcb a plate with the threads for the screws

On Sat, 19 Mar 2022 13:19:50 -0400, legg <legg@nospam.magma.ca> wrote:

>On Fri, 18 Mar 2022 19:23:37 -0700, jlarkin@highlandsniptechnology.com
>wrote:
>
>>https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>
>Use the center legs to conduct, but rotate bodies to allow tabs to
>face the cooling surface.
>
>RL

The fets will have AlN insulators between their drain tabs and the
copper heat sink. All electrical connections will be through the pins,
sorta surface mounted.

We'll tap a hole in the center of the copper pedistal. A giant fender
washer with some compliant stuff will squash the fets down, with the
center screw applying the force.

I guess I shouldn't have any vias under that copper thing.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

On Sat, 19 Mar 2022 14:42:13 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>lørdag den 19. marts 2022 kl. 21.58.36 UTC+1 skrev jla...@highlandsniptechnology.com:
>> On Sat, 19 Mar 2022 11:38:14 -0700 (PDT), Lasse Langwadt Christensen
>> <lang...@fonz.dk> wrote:
>>
>> >lørdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
>> >> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
>> >> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
>> >> > wrote:
>> >> >
>> >> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >> >
>> >> > Use the center legs to conduct, but rotate bodies to allow tabs to
>> >> > face the cooling surface.
>> >> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
>> >
>> >it's rated for 125W TPD and CPU are usually 100'C max Tj
>> >
>> >0.29 C/W with the fan at max speed
>> >
>> >https://www.dynatron.co/product-page/k199
>> >
>> >
>> I measured 0.24, which is pretty good in the thermal business.
>>
>> The hot air will blow right out the back of the box. The main box fans
>> might help a little too.
>>
>> I might have a lot of topside copper under the heat sink, with many
>> thermal vias to, well, somewhere. That would help a bit too, maybe
>> 5-10%, use some PCB surface area in the air flow.
>>
>> There are hunkier coolers around, but I don't have height for them.
>
>you could also skip the hole and put the transistors with the tap side
>up on the top of the pcb, so the whole sandwich is: heatsink, transistors,pcb
>and on the back of the pcb a plate with the threads for the screws
>

That might be hard to assemble.

We'll make a 3D printed plastic fixture to align the four fets, with
their insulators, before we solder them down and then scrunch down the
clamp thing.

That's only moderately hard to assemble.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon

mandag den 21. marts 2022 kl. 20.13.32 UTC+1 skrev John Larkin:
> On Sat, 19 Mar 2022 14:42:13 -0700 (PDT), Lasse Langwadt Christensen
> <lang...@fonz.dk> wrote:
>
> >lørdag den 19. marts 2022 kl. 21.58.36 UTC+1 skrev jla...@highlandsniptechnology.com:
> >> On Sat, 19 Mar 2022 11:38:14 -0700 (PDT), Lasse Langwadt Christensen
> >> <lang...@fonz.dk> wrote:
> >>
> >> >lørdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
> >> >> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
> >> >> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology..com
> >> >> > wrote:
> >> >> >
> >> >> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
> >> >> >
> >> >> > Use the center legs to conduct, but rotate bodies to allow tabs to
> >> >> > face the cooling surface.
> >> >> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
> >> >
> >> >it's rated for 125W TPD and CPU are usually 100'C max Tj
> >> >
> >> >0.29 C/W with the fan at max speed
> >> >
> >> >https://www.dynatron.co/product-page/k199
> >> >
> >> >
> >> I measured 0.24, which is pretty good in the thermal business.
> >>
> >> The hot air will blow right out the back of the box. The main box fans
> >> might help a little too.
> >>
> >> I might have a lot of topside copper under the heat sink, with many
> >> thermal vias to, well, somewhere. That would help a bit too, maybe
> >> 5-10%, use some PCB surface area in the air flow.
> >>
> >> There are hunkier coolers around, but I don't have height for them.
> >
> >you could also skip the hole and put the transistors with the tap side
> >up on the top of the pcb, so the whole sandwich is: heatsink, transistors,pcb
> >and on the back of the pcb a plate with the threads for the screws
> >
> That might be hard to assemble.
>
> We'll make a 3D printed plastic fixture to align the four fets, with
> their insulators, before we solder them down and then scrunch down the
> clamp thing.
>
> That's only moderately hard to assemble.

if you mount the transistor on top with the tap facing up, you just put something like this
https://www.amazon.com/uxcell-Heatsink-Cooling-Backplate-Motherboard/dp/B00GN7Z20W
on the back of the board, put on the heatsink and tighten the four screws

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
> l??rdag den 19. marts 2022 kl. 09.22.54 UTC+1 skrev Jan Panteltje:
>> On a sunny day (Fri, 18 Mar 2022 19:23:37 -0700) it happened
>> jla...@highlandsniptechnology.com wrote in
>> <4afa3hlpivlfi9hq1...@4ax.com>:
>> >
>> >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >
>> >This might not be as good as a gigantic machined heat sink, but it's
>> >easier.
>> >
>> >The little guy will be an LM35 temperature sensor.
>> Not sure about the air flow
>> Is there space between the fan and the surface?
>
> airflow goes in through the sides of the heatsink between the fins, up through the fan and out the back

It's the perfect design to make a crappy fan die faster than usual.

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
> l??rdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
>> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
>> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
>> > wrote:
>> >
>> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >
>> > Use the center legs to conduct, but rotate bodies to allow tabs to
>> > face the cooling surface.
>> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
>
> it's rated for 125W TPD and CPU are usually 100'C max Tj
>
> 0.29 C/W with the fan at max speed
>
> https://www.dynatron.co/product-page/k199

Those are some pretty optimistic numbers for a new fan, with a clean
heatsink, in an infinitely cooled room at 25C.

onsdag den 23. marts 2022 kl. 22.08.07 UTC+1 skrev Cydrome Leader:
> Lasse Langwadt Christensen <lang...@fonz.dk> wrote:
> > l??rdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
> >> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
> >> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
> >> > wrote:
> >> >
> >> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
> >> >
> >> > Use the center legs to conduct, but rotate bodies to allow tabs to
> >> > face the cooling surface.
> >> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
> >
> > it's rated for 125W TPD and CPU are usually 100'C max Tj
> >
> > 0.29 C/W with the fan at max speed
> >
> > https://www.dynatron.co/product-page/k199
> Those are some pretty optimistic numbers for a new fan, with a clean
> heatsink, in an infinitely cooled room at 25C.

really? that's must why the spec sheet say @ 35'C ambient ...

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
> onsdag den 23. marts 2022 kl. 22.08.07 UTC+1 skrev Cydrome Leader:
>> Lasse Langwadt Christensen <lang...@fonz.dk> wrote:
>> > l??rdag den 19. marts 2022 kl. 19.23.00 UTC+1 skrev Rickster:
>> >> On Saturday, March 19, 2022 at 1:19:27 PM UTC-4, legg wrote:
>> >> > On Fri, 18 Mar 2022 19:23:37 -0700, jla...@highlandsniptechnology.com
>> >> > wrote:
>> >> >
>> >> > >https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>> >> >
>> >> > Use the center legs to conduct, but rotate bodies to allow tabs to
>> >> > face the cooling surface.
>> >> The transistors are on the bottom of the board, not sandwiched between the heat sink and the fan. The fins are very, very short on the top side of the heat sink, just under the fan which is moving air through the heat sink with a vacuum. Normally the fans blow into heat sinks, but in this case there's no room for that.
>> >
>> > it's rated for 125W TPD and CPU are usually 100'C max Tj
>> >
>> > 0.29 C/W with the fan at max speed
>> >
>> > https://www.dynatron.co/product-page/k199
>> Those are some pretty optimistic numbers for a new fan, with a clean
>> heatsink, in an infinitely cooled room at 25C.
>
> really? that's must why the spec sheet say @ 35'C ambient ...

Good luck with that thing either way, even at 35.

On Fri, 18 Mar 2022 19:23:37 -0700, jlarkin@highlandsniptechnology.com
wrote:

>
>https://www.dropbox.com/sh/xq91kwztbqfwn72/AACBtWvHaB1JBDfkTsF4wGmCa?dl=0
>
>This might not be as good as a gigantic machined heat sink, but it's
>easier.
>
>The little guy will be an LM35 temperature sensor.

Here's the bottom of the cooler. The metal washer scrunches a neoprene
washer onto the fets to push them against the copper heat sink.

https://www.dropbox.com/s/bz6ueadispq6ril/CPU_Cooler_Washers.jpg?raw=1

There is, technically, 1800 watts of mosfet under there.

I ordered a custom AlN insulator to complete the stack.

--

I yam what I yam - Popeye