i am in need of a heatsink to go on top of a chassis. Its for a TO-247 mosfet. specifically one running at 24vdc and 2.5A.
I would like a 0.5C/W heatsink if possible. I have been looking around and for whatever reason having a hard time finding one. I would of course have to tap a hole to mount the device on the heatsink.
Any help would of course be appreciated.
I would like a 0.5C/W heatsink if possible. I have been looking around and for whatever reason having a hard time finding one. I would of course have to tap a hole to mount the device on the heatsink.
Any help would of course be appreciated.
one side of 4U/300 Modushop case is well adequate for that, one mosfet with more than 50W of heat must be well cooled
that's your reference
that's your reference
More Modushop heat sink information:
40mm Heatsinks – diyAudio Store
Note that mounting a heat sink horizontally will reduce its efficiency.
40mm Heatsinks – diyAudio Store
Note that mounting a heat sink horizontally will reduce its efficiency.
That's a lot of wasted power, needing a large, heavy, expensive heat sink. This is why linear regulators
for high power are seldom used. Some ways to mitigate the device loss: a preregulator; a series or shunt
power resistor; separate regulators per channel. But the same total amount of power will still be burned.
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yup
I was thinking that it goes on top, while still being properly oriented, with some clearance
if going horizontal ............ double
I was thinking that it goes on top, while still being properly oriented, with some clearance
if going horizontal ............ double
My thoughts were to mount the heatsink on the top of the enclosure... but i am wondering also if that would reduce its ability to sink heat... as airflow cannot come up from underneath the fins and through to the top... only from side to side.
thank you for that link!!
thank you for that link!!
No reasons why not to use them.
An arguably better replacement for the resistor in a CRC power supply - R21 PS module
oh thank you for that link on mounting devices and heatsinks. What is the current thoughts for mounting a TO247 onto a heatsink? directly? or with insulator / thermal grease etc?
I will also read that article.
I will also read that article.
The TO-247 requires galvanic isolation from the heat sink, since the metal tab on its back is connected
internally to the drain or collector terminal. A die-cut thermal isolation pad is needed.
internally to the drain or collector terminal. A die-cut thermal isolation pad is needed.
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You definitely want to use something inbetween. (Keratherm or some similarly effective materials)
You might avoid mica if isolating heatsink metal from rest of chassis but in my point of view, that´s an accident waiting to happen.
As of dissipation itself: would you consider some kind of fan?
Blowing air across, along fins, whichever way is most efficient.
If noise worries you, an undervolted fan, as in running a 12V one from meager 9V or even 6-7 V will turn a storm (ok, a small one 🙂 ) into gentle breeze, inaudible unless you put your ear within 5 cm of it.
No need for a strong wind at all, just "moving" hot air away (instead of letting it accumulate in "hot bubbles") replacing it a couple times a minute will do wonders .
Don´t take my word for it, just try it.
You can make small screens and baffles out of thin metal, including scissor hand cut Coke can aluminum to send it the proper way.
As of dissipation itself: would you consider some kind of fan?
Blowing air across, along fins, whichever way is most efficient.
If noise worries you, an undervolted fan, as in running a 12V one from meager 9V or even 6-7 V will turn a storm (ok, a small one 🙂 ) into gentle breeze, inaudible unless you put your ear within 5 cm of it.
No need for a strong wind at all, just "moving" hot air away (instead of letting it accumulate in "hot bubbles") replacing it a couple times a minute will do wonders .
Don´t take my word for it, just try it.
You can make small screens and baffles out of thin metal, including scissor hand cut Coke can aluminum to send it the proper way.
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If I may add 2c…
Mark had once started an interesting thread:
Fan inside audio chassis: variable speed, temperature controlled, analog. No PWM.
Plus, if I‘d had a heatsink laying on the top-cover, I‘d perforate its base around / near the „hardest working area, to try to get more airflow and avoid stuck heat…
Mark had once started an interesting thread:
Fan inside audio chassis: variable speed, temperature controlled, analog. No PWM.
Plus, if I‘d had a heatsink laying on the top-cover, I‘d perforate its base around / near the „hardest working area, to try to get more airflow and avoid stuck heat…
If you choose to be blunt 😉
GThere are high power amps with BIG top horizontal heatsinks .... BUT they are all fan cooled and have baffles and covers to direct air flow along fins:
left half:
air is injected from below between both halves and exits on the sides after travelling along fins.
GThere are high power amps with BIG top horizontal heatsinks .... BUT they are all fan cooled and have baffles and covers to direct air flow along fins:
An externally hosted image should be here but it was not working when we last tested it.
left half:
air is injected from below between both halves and exits on the sides after travelling along fins.
Of course the simplest heatsink is to reduce the size or eliminate it. If you know the minimum and maximum input voltage to the transistor and the current through it, you may be able to add a component or two to reduce the dissipation in the transistor.