Temperature protection for dummyload ?

[piotres]

Hi

I'm bit frustrated, I've just burned my dummyload second time (215W) . I forgot to plug it off from socket after turning down unit and some minutes after I saw only a lot of smoke in mine room . Enclosure from evap melts in half and after 10 minutes kprobe on evap was showing more than 170*C ..but it's all reparaible .

But... I don't want to make that again ...guys please write here how to make a protection for 230V dummyload ? Eg. Turn dummy off when temperature is over +50*C .

Now I plan to make around 230W new dummyload, because one or three resistors in mine just killed 215W dummy broke down . So I'll buy new resistiors, for little stronger dummy.

Thanks
Regards
Peter

[K404]

Do you have any thermostats around? You could hook a temp probe up and also run the dummy through it and set it to kill the circuit and whatever temperature you like

[harvshark]

How about a simple HVAC snap disk tstat like these? They come in different temp ranges. Use a 'open on rise' type wired in series with your power input and they will open the circuit and shut the dummy load off when it gets too hot, automatically turning back on when it cools off. You probably all deal with HVAC suppliers that have these things.

http://www.grainger.com/Grainger/wwg...ed=Snap-Action

EDIT.....
Ooops, that link doesn't quite work.....type 'snap disk' in the right hand search blank at the top of the page.

[DetroitAC]

I was thinking the same thing as harvshark. Snap disc thermostat is very reliable and very cheap, can just be wired in series to the heater.

[Dimas]

a NTC/PTC thermostat can do the trick, cut off heater after 30°C...

[wdrzal]

Originally Posted by DetroitAC

I was thinking the same thing as harvshark. Snap disc thermostat is very reliable and very cheap, can just be wired in series to the heater.

Agreed, they are cheap

you can also just wire the dummy load to same circuit after the on/off switch as compressor,as 200 watt dummy @ 120v is less than 2 amps,plus compressor you should not overload circuit. when compressor is off dummy load is off.,unless you have massive mass on dummy load the residual cooling should cool dummy load down, when load and compressor are shut off together. I do believe in limit switches,they make the system (dummy proof) It's a normal practice to protect all circuits from overloading/heating in some way.

[johann]

I use a simple thermal cut off switch, it cuts the circuit at around 60c and only cost about $1