L
legg
Guest
On Sat, 19 Mar 2022 10:35:10 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
RL
<langwadt@fonz.dk> wrote:
RL
L
legg
Guest
On Sat, 19 Mar 2022 10:35:10 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
the cooling surface - not as illustrated in mock4.
RL
<langwadt@fonz.dk> wrote:
The cooling surface is attached to the fan fins. The tabs should face
the cooling surface - not as illustrated in mock4.
RL
L
Lasse Langwadt Christensen
Guest
lørdag den 19. marts 2022 kl. 20.09.24 UTC+1 skrev legg:
the tabs are facing the cooling surface, mock4 is a bottom view,
shows the transistors mounted through a hole in the PCB
the tabs are facing the cooling surface, mock4 is a bottom view,
shows the transistors mounted through a hole in the PCB
L
Lasse Langwadt Christensen
Guest
lørdag den 19. marts 2022 kl. 20.04.20 UTC+1 skrev legg:
no
no
W
whit3rd
Guest
On Saturday, March 19, 2022 at 6:30:23 AM UTC-7, jla...@highlandsniptechnology.com wrote:
It\'s not completely ideal; the airflow favors cooling the side opposite the
outlet. A ribbed plate with air flowing parallel to the ribs would ensure
some heatflow uniformity regardless of lateral conduction in the plate.
For serious cooling, your fan can be one-per-box, and air channeled not by
objects clamped to the printed wiring board, but by vanes riveted to the box.
The tiny internal fan, even though it may be effective, is not as easy to inspect
or replace as a muffin fan mounted to the box/chassis. Moving parts,
substantial failure possibilities...
It\'s not completely ideal; the airflow favors cooling the side opposite the
outlet. A ribbed plate with air flowing parallel to the ribs would ensure
some heatflow uniformity regardless of lateral conduction in the plate.
For serious cooling, your fan can be one-per-box, and air channeled not by
objects clamped to the printed wiring board, but by vanes riveted to the box.
The tiny internal fan, even though it may be effective, is not as easy to inspect
or replace as a muffin fan mounted to the box/chassis. Moving parts,
substantial failure possibilities...
T
three_jeeps
Guest
On Saturday, March 19, 2022 at 9:30:23 AM UTC-4, jla...@highlandsniptechnology.com wrote:
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
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
S
server
Guest
On Sat, 19 Mar 2022 12:41:57 -0700 (PDT), three_jeeps
<jjhudak@gmail.com> wrote:
Thermal theories are nice, but I believe experiments.
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
<jjhudak@gmail.com> wrote:
Thermal theories are nice, but I believe experiments.
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
S
server
Guest
On Sat, 19 Mar 2022 12:23:36 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
I cut that on our classic Bridgeport milling machine. Just ignore the
obvious goof.
--
I yam what I yam - Popeye
<langwadt@fonz.dk> wrote:
I cut that on our classic Bridgeport milling machine. Just ignore the
obvious goof.
--
I yam what I yam - Popeye
L
Lasse Langwadt Christensen
Guest
lørdag den 19. marts 2022 kl. 21.41.31 UTC+1 skrev jla...@highlandsniptechnology.com:
murphys law also apply to the handles moving the table on milling machine
murphys law also apply to the handles moving the table on milling machine
S
server
Guest
On Sat, 19 Mar 2022 11:38:14 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
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
<langwadt@fonz.dk> wrote:
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
L
Lasse Langwadt Christensen
Guest
lørdag den 19. marts 2022 kl. 21.58.36 UTC+1 skrev jla...@highlandsniptechnology.com:
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
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
J
John Larkin
Guest
On Sat, 19 Mar 2022 13:19:50 -0400, legg <legg@nospam.magma.ca> wrote:
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
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
J
John Larkin
Guest
On Sat, 19 Mar 2022 14:42:13 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
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
<langwadt@fonz.dk> wrote:
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
L
Lasse Langwadt Christensen
Guest
mandag den 21. marts 2022 kl. 20.13.32 UTC+1 skrev John Larkin:
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
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
C
Cydrome Leader
Guest
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
It\'s the perfect design to make a crappy fan die faster than usual.
It\'s the perfect design to make a crappy fan die faster than usual.
C
Cydrome Leader
Guest
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
Those are some pretty optimistic numbers for a new fan, with a clean
heatsink, in an infinitely cooled room at 25C.
Those are some pretty optimistic numbers for a new fan, with a clean
heatsink, in an infinitely cooled room at 25C.
L
Lasse Langwadt Christensen
Guest
onsdag den 23. marts 2022 kl. 22.08.07 UTC+1 skrev Cydrome Leader:
really? that\'s must why the spec sheet say @ 35\'C ambient ...
really? that\'s must why the spec sheet say @ 35\'C ambient ...
C
Cydrome Leader
Guest
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:
Good luck with that thing either way, even at 35.
Good luck with that thing either way, even at 35.
S
server
Guest
On Fri, 18 Mar 2022 19:23:37 -0700, jlarkin@highlandsniptechnology.com
wrote:
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
wrote:
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