Hi everyone,
I'm looking for a standard part / component that switches off my power supply if the temperature of my device turns more than 42°C (as a safety feature).
Looking at available thermal cutoffs / fuses / switches, they have two advantages: 1. typically they react on higher temperatures (60°C and above) and 2. they have a tolerance that is too large (I need +-0.5°C).

Of course I can take a NTC thermistor, a controller and a relay and make a small PCB myself, nevertheless I would prefer something already existing or a standard component. After research, I couldn't find anything.
Looking forward to be pushed in the right direction

Thanks everyone!

 

hi peito,
If its a safety feature ie: a cut off at over 42C, why do you require the +/-0.5C tolerance band.?
E

 

hi peito,
If its a safety feature ie: a cut off at over 42C, why do you require the +/-0.5C tolerance band.?
E

To make sure, that before 43°C (latest 42.5) the power supply is cut.

 

hi,
OK.
The way your first post reads, is that the cut off operates at ideally 42C but always over 42.5C and cuts back in at 41.5C.

I have some Amazon Temperature modules that would do what you need.
I will post the link.
E

EDIT:
This type can be set for ON Cooling or ON for Heating, the ones I have fine, not expensive.
https://www.amazon.co.uk/SODIAL-Dig...23&sr=8-3&keywords=temperature+control+module

typo:

 

Looking at available thermal cutoffs / fuses / switches, they have two advantages: 1. typically they react on higher temperatures (60°C and above) and 2. they have a tolerance that is too large (I need +-0.5°C).

You may want to give this a read. Most inexpensive temperature sensing systems will not offer the tolerance you seem to want. That would be true of using thermistor sensors as well as thermocouples. If you can live with a wider tolerance then I would just get a board like Eric linked to from Amazon.

Ron

 

If it's just to protect your supply, I see no reason for such a tight tolerance on the temperature cutoff.
It complicates the design and seems unnecessary.
A tolerance of a few degrees C should be entirely adequate. You can make the upper limit on the tolerance 42°C.

 

I agree. It sounds like a false sense of precision. Can you really prove to yourself or anyone here that 42C is fine while 43C is unacceptable? If 43C is truly risky, then so is 42C.

 

I doubt you could build something like this for the price if you brought the components separately.

https://www.ebay.co.uk/itm/W1209-DC...var=492422927289&_trksid=p2060353.m1438.l2649

You might be able to configure the unit powered by your PSU (it needs a 12Vdc supply) with the relay switching off/on the output of the PSU to your load.

The ebay seller also sells a plastic enclosure for the unit, if required.

[I see that ericgibbs has posted a link to an Amazom seller of the item (which is more expensive)]

 

hi Hymie,
The eBay is £1.31 each

Amazon 4 for £2.47 which is cheaper.. if you read it one way.
The other way they show two in the advert.???

E

EDIT:
Just checked my last order its was £2.47 for 2 units, so £1.22 each, still cheaper.

 

Hi everyone,
Thanks for your feedback. I ordered one and will give it a close look