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June 18, 2019, 13:49:11 PM

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Author Topic: High current power supplies  (Read 36751 times)

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Online PDR

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Re: High current power supplies
« Reply #80 on: February 25, 2015, 12:36:02 PM »
The response to that pin is proportional (it's not just a switch) so if you want to be clever you can mount a thermister in the fan exhaust and connect it across those pins to have a temperature-regulated fan.

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Re: High current power supplies
« Reply #81 on: February 25, 2015, 13:10:39 PM »
why would you put it in the fan exhaust, if thats getting hot it's too late, and then the extra flow will cool it too quick. better to stick it on the hot thing.
I know you believe you understand what you think i said, but i am not sure you realise that what you think you heard is not what i meant.

Offline Mike_T

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Re: High current power supplies
« Reply #82 on: February 25, 2015, 13:42:13 PM »
why would you put it in the fan exhaust, if thats getting hot it's too late, and then the extra flow will cool it too quick.
Because it acts like a governor, not a safety valve.

I got the impression from some of the stuff I read, that the fan speed would increase anyway if overheating were detected  $%&


Offline Andy_S_T

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Re: High current power supplies
« Reply #83 on: February 25, 2015, 14:38:26 PM »
Pretty sure I have a two way switch somewhere in the garage, so that'll be tonights project.

As a mechanical/structural engineer I'm finding this electricary quite fun! I'm slowly gaining more understanding and knowledge, it's like going back to uni!

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Re: High current power supplies
« Reply #84 on: February 25, 2015, 16:06:15 PM »
why would you put it in the fan exhaust, if thats getting hot it's too late, and then the extra flow will cool it too quick. better to stick it on the hot thing.

What hot thing? You don't want to open-up the case to try to find the relevant bit (the driver FETs? the inductors? the flux capacitors?) because (a) you don't know which part to use as the temperature reference and (b) in doing so you'd clog up an already close-fitting cooling air path, possibly causing the very overheating you're trying to prevent.

Place the thermister in the exhaust air and it will increase the fan speed as the air heats up and reduce it as it cools down. The power supply itself already has over-temp shutdown protection - all this is doiung is reducing the fan speed unless and until it's needed. The alternative (just shorting the link and setting the fan permanently slow) won't risk damaging the power supply, but it will risk it shutting down when it didn't need to.

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Re: High current power supplies
« Reply #85 on: February 25, 2015, 16:27:14 PM »
reccomended resistance value and temp range??
I know you believe you understand what you think i said, but i am not sure you realise that what you think you heard is not what i meant.

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Re: High current power supplies
« Reply #86 on: October 08, 2015, 14:56:04 PM »
I ordered my power supply today.

For anyone who's into this, here's an interesting site:

http://www.tjinguytech.com/my-projects/diy-24v-47a
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