Cabinet Temperature Controller

lowest I can go is 9.4 KHz - and it works better - why a IRL3803 cause thet is what I had in my parts bin.

Davrus,
Generally I only supply to people local to me - for two reasons:
  • I am not set up to do decent type testing so I can promise it will work is all situations
  • If they have an issue, I can get in my car and go sort it out.
There is some really good off the self stuff out there as some others have pointed out. It may suit you needs better.
Have a look at this wonder product.
 
QFK
The more I play with the PWM the more I appreciate your suggestion to run it at a lower frequency. Thanks a lot.
 
Have a look at this little device. It does everything you want and some more, you don't need to program it, and the thermal sensor is built in. If you put a couple of dip switches on it, it could drive your fet.

http://datasheets.maximintegrated.com/en/ds/MAX6643-MAX6645.pdf


Everytime you turn on/off the FET, it has to pass through its linear zone. it sucks energy. If you do that 1M times a second, thats 100x more energy than doing it at 10khz. Theres also the gate charge you need to think bout.
 
They work well as well, I use them quite a bit. Theres so many special purpose ICs' these days that mostly the job is looking for it. Theres a good chance that if you have the specific problem someone may have had it before you.
 
Wow, just came across this older thread and wanted to offer how I cooled my power supply cabinet for my pixels. I did it a very simpler way. Much simpler and VERY reliable.

I have a power supply box that has 12 SE350 5V Meanwell power supplies (see enclosed photo). This box obviously needed to be cooled when the pixels were running or when outside temperature caused the internal temperature to rise. I had to protect my power supplies as well as make sure that everything was working properly.

I selected a simple 'snap' switch which closes at a pre-determined temperature. I chose 20 degrees celcius which is approx. 70 degrees Fahrenheit here in the USA. When the switch determines that the internal temperature has risen over 20 degrees, then the switch closes and provides AC power to my AC fans. I have two 120VAC fans in the cabinet as well as two 'inlets' for providing input cooling.

Everything worked perfectly last year with the enclosure cooling. No issues what so ever, however I should mention that I built into the design a manual fan shutoff and a manual 'on' switch which is wired in parallel with the snap switch to test everything and to have the availability of by-passing the fan.

If you look just above the portable temp monitor, you will see the manual 'on' switch and just to the right of the switch you will see the snap switch. WAY easier and cheaper to cool your enclosure. Also MUCH more reliable. --Greg--
 

Attachments

  • 20141227_161230.jpg
    20141227_161230.jpg
    886.5 KB · Views: 48
  • 20141227_161225.jpg
    20141227_161225.jpg
    922.7 KB · Views: 47
hi,
Your temp controller looks good. but i think it is overkill. I'm a firm believer of the KISS principle. Personally i would just let the fans run all the time….better to have it failsafe, then not to run in the event that the controller failed. And I would do a test on the enclosure to see what temps it ran at. no good having it turn off at <40 oC it the box never goes there. :-\


Some observations that may help you. I recently bought a "top Quality" ( hey it had stickers on the side saying so) 300W 5v PS from china. it came with a fan that was controller by a tempswitch (simple) that was set to operate at >45 deg C.


When loaded at 60 A ( I bench tested it) the PS box ( near the Heat sinks) would run at around 50 oC which according to the sticker was its operational max. :mad: and the fan would cycle in and out based on the internal temp at the switch.


I disconnected the temp switch and bridged it out so that the fan ran continuously and the box temp fell to about 46 oC, not much better but better than the cycling fan version.
Lightly loaded the PS ran at about 32 oC.


I don't know where you are but here we get summer nights that are above 30 oC. so for me the box isn't going to get below that anyway, so i want all the cooling i can get.


If you are somewhere that is colder at night, then keeping the box at a "nice" temp will help prevent condensation, in which case having the fans turn off if it gets too cold would help.


If you use the controller then you may want to consider closing the on/off temp gap to try and maintain a constant temp. from my experience most electronics is happy at a constant temp instead of being thermally cycled.

Cheers
Fing
 
My method is to use a meanwell HRP power supply as these are very reliable but also have a fan on the end and air flows across the whole power supply.
I fit this into a smaller box where the power supply and controller fit snuggly and then fit vents on either side of the control box. This allows the air to be directly suicked from outside and then blown back out using the meanwell built in fan and control, this ensures that temps never get too high and im not relying on a secondary fan circuit to remove the heat. Ill need to add some pictures next time i build some more to show the design.
 
One of Eds boxes. You can see the vents on either end. The power supply is underneath with the controller on top.
 

Attachments

  • ImageUploadedByTapatalk1423449819.228164.jpg
    ImageUploadedByTapatalk1423449819.228164.jpg
    155.5 KB · Views: 41
Christmas @ the Myrtle (Michael) said:
One of Eds boxes. You can see the vents on either end. The power supply is underneath with the controller on top.
Click to expand...

Thanks for sharing as that makes it much easier for others to understand and how we can stuff a 450 watt power supply into a small box without any temperature issues.
 
Greg.Ca said:
Wow, just came across this older thread and wanted to offer how I cooled my power supply cabinet for my pixels. I did it a very simpler way. Much simpler and VERY reliable.

I have a power supply box that has 12 SE350 5V Meanwell power supplies (see enclosed photo). This box obviously needed to be cooled when the pixels were running or when outside temperature caused the internal temperature to rise. I had to protect my power supplies as well as make sure that everything was working properly.

I selected a simple 'snap' switch which closes at a pre-determined temperature. I chose 20 degrees celcius which is approx. 70 degrees Fahrenheit here in the USA. When the switch determines that the internal temperature has risen over 20 degrees, then the switch closes and provides AC power to my AC fans. I have two 120VAC fans in the cabinet as well as two 'inlets' for providing input cooling.

Everything worked perfectly last year with the enclosure cooling. No issues what so ever, however I should mention that I built into the design a manual fan shutoff and a manual 'on' switch which is wired in parallel with the snap switch to test everything and to have the availability of by-passing the fan.

If you look just above the portable temp monitor, you will see the manual 'on' switch and just to the right of the switch you will see the snap switch. WAY easier and cheaper to cool your enclosure. Also MUCH more reliable. --Greg--
Click to expand...
Firstly I didn't set out to make a cheap HoHoHo solution. I set out to use what I had available.
Bymetal strip have their place. sure. But I am lacking to see how using multiple metal interfaces conducting heat from the base plate is "better" than measuring the ambient air temperature.
I am also failing to see how turning them on at 20 degree C is "better" than just leaving them to run at full speed permanently. Where as my fan turn on slowly and ramp up as the temperature rises higher. On coolish days they stayed off or turned on for short periods only.

Finally Please explain HOW and mechanical Bimetal switch is MUCH more reliable than an electronic cct.
 
You must log in or register to reply here.
Back
Top