Adjustable thermal switch for Avionics Fan
 

I've been searching for one of these, most at Mouser are defined as thermostats and are fixed range, I want to cable it up but be able to adjust the engagement point so I can control when my fans cut on- does anyone know a source for these types of switches?

I have one in my box-o-junk that I have been hauling around since I was 15...one day I will find a use for it...haha. I think it came from one of those cheap space heaters. You may want to check out an HVAC shop or parts website.

i have, the probably with heaters is they turn on when it is cold, i want something that turns on when it is hot. Weight/simplicity are also key factors but above all others, i want to be able to adjust engagement points

Probably more complex than you want:

http://www.amazon.com/Hayden-Automot...thermal+switch

You can always just use a small relay to reverse the swiching.

..... I purchased one that was very small, light weight, fully adjustable for temperature as well as the fan speed. I got it at one of the computer shows and it was intended for use in high end desk tops to cool the processors. You might do a search related to this and come up with something ideal. Allan...:D

i have been looking on newegg, some of these look like parts of the space shuttle program, what happened to keeping things simple!

Here is the type of switch I have. Perfect for what you are doing assuming you are basing the switching on cabin temp rather than unit temp.

http://sell.bizrice.com/selling-lead...al-Switch.html

that's exactly what i'm looking for, now just have to find a good supplier/source for it. simple is best and that is what this switch is

I would not recommend this for switching DC power, it's contacts are only rated for AC operation. Despite it's high AC current rating there is no corresponding DC rating. Typically contacts (switches, relays, etc.) which are rated for AC operation can only handle a tiny fraction of that in a DC load. The safe route is to find a device which is intended to switch a DC load and is rated appropriately for that load. Something with an intended application in a PC may be closer to what you're looking for.

here is another option if you want flashy, look at most any real computer store, and get a hardware monitor, will give you a digital readout of usually upto 5 thermal probes ( included) has 12 volt DC output and adjustable set points to turn fan on and off inside a computer, even vary speed if desired, again most have 5 inputs and outputs, just check the ratings, the better units will support upto 1.5 amps at 12 volt per output, and todays muffin fans for PC's are quiet and small sized with amazing airflow.

the only quirk I see to this plan, they want 12 volts IN, not the 13.8, so may have to tweak the input voltage a little to get it to play nice with the onboard power.

Yea I know, I never said it would be a drop in,but it would give a nice display to actually monitor the radio stacks/ glass panels yada yada. and you can get probes upto 5 feet long very easily.