Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

temperature sensor for TEC fridge

Status
Not open for further replies.

Dr_Doggy

Well-Known Member
I got a peltier cooler, which stopped heating , opened up control circuit and very interesting design tactic, it feeds 12v to a dpdt switch setup as h-bridge, the switch feeds leds to show bias and in parallel with that feeds TEC module, after that , and what i found interesting was that in parallel again was a rectifier that feeds fan motors, so they dont reverse when reversing polarity, anyway i found interesting.

In series with my TEC and rectifier is a thermal sensor which seems to cut off current when TEC goes above or below temperature range, however i think it is that sensor that has fried. because when i switch to cool it never stops and when i switch to heat it never starts, there are lots of temp sensors at my vendor, but i have problem finding the specific one, or any that fit that shape
I hope someone can tell me proper name of what im looking for, maybe where to find them
I will be able to ensure specs myself , but so far cannot find anything like this item:, here is best image:
 

Attachments

  • 20150607_204912.bmp
    553.8 KB · Views: 244
  • 20150607_204916.bmp
    531.9 KB · Views: 211
It is a bimetallic switch, that sort of device I have only even seen for safety, rather than for control.
Mini fridges with heat pumps in them usually specify a temperature below ambient for the contents, so I assume the heat pump runs all the time.
Might be a collectors item that coke fridge, if not now when they have nearly all gone.
Look on the device, it should be marked on somewhere the temperature it switches at, being a safety device its probably max or hot temp, I'd guess about 50 degrees, but do replace it with the same if you don't want a fire.
 
it doesn't really work on cool either cause it never shuts off, which is inverse to heat which never turns on. both polarities work when i short out the sensor. which is what lead me to my conclusions

but thanks, its the big words that always get me "thermostatic bimetal snap switch", I should be able to find the right one from that link


DR thanks for conf , It is exactly that , a coke cola collectors fridge, i forget now but it cost me around 100-300 $, thought i seen a vague part number, but was going to guage for +-20deg, since running it , it didnt seem to go below 4 degrees Celcuis, unfortunately i damaged the back sticker that covered the screws, that will prolly decrease value a bit, oh well though, at least i will get it working again

thanks guys!
 
Last edited:
ac250v/10aac125v/15a is the only info provided on back, but thnx again! i should be good from here!~
 
See if you can find what temp its sposed to warm to, and choose your temp switch from that.
I'd find an old plate from some equipment, power rating plate or something and stuff that over the damaged area.
 
With Peltier type fridges the thermostat in the picture you posted will be an over temp sensor for heating. Heres a picture of a typical peltier fridge, theres no need for a thermostat for cooling, as they are only capable of about zero degrees C cooling in practice. As the external temperatures rise above 25deg C, so does the internal temperature. They are just barely a cooler, but they work very well as a heater if you reverse the polarity to the peltier device, that's why theres a temp sensor. Last pic is after 8Hrs with an ambient temp of 25degC. The internal thermal sensor on this fridge is 90degC for heating mode, which I have disabled as I didnt want it for heating.
PELTIER FRIDGE Foam walls 40mm..JPG
PELTIER FRIDGE.JPG
TEMP After 8Hrs Amb 25 deg C.JPG
 
Nice, i think mine is the same since it's supply is rated at 12v 5 amp also, plus again about the +/-20 from ambient, I got this thing initially for cool drinks, but I have discovered that the hot setting is perfect for melting "glue gun glue sticks" , actually it softens them just perfectly to release the stickiness, I use the glue a lot when i want to make molds for epoxy. In this image i used the epoxy to glue in my audio bus.

EDIT: re-posted tv question!
 

Attachments

  • 20150614_155223.bmp
    576.1 KB · Views: 170
Last edited:
ohya! ghetto huh!

but more important Tec works great , she is purring now!

thnx again!
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top