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Bimetal thermostats are used in a variety of products, even in your toaster or electric blanket. But what are they and how do they work?
Read on to learn more about these thermostats and how Calco Electric can help you find the best one for your project.
What Is a Bimetal Thermostat?
A bimetal thermostat is a device that uses two metals that react differently to heat. One of the metals will expand more rapidly than the other when exposed to heat, creating a round arc. The pairing is typically copper and steel or a copper alloy like brass and steel.
As the temperature gets hotter, the more pliable metal (for instance, the copper) will arc so much that it opens a contact and shuts off the electricity to the circuit. As it gets colder, the metal contracts, closing the contact and allowing the electricity to flow again.
The longer this strip is, the more sensitive it is to temperature changes. That’s why you can often find these strips in tightly wound coils.
A thermostat like this is extremely cost effective, which is why they’re in so many consumer appliances.
How Does a Bimetal Thermostat Switch On and Off?
These thermostats are designed to be self-regulating. As the temperature increases, the system switches off. As it cools, it switches back on again.
In your home, this means you simply have to set a temperature and it will regulate when the furnace (or air conditioner) turns on and off. In the case of a toaster, the strip will shut off the heat and trigger the spring that pops the toast up.
Not Just for Your Furnace
Have you ever had a piece of toast that came out black when you didn’t want it? That could be the result of a faulty bimetal thermostat. These devices are everywhere in your home, from your toaster to your dryer to your iron.
These little things are a key safety feature. If your iron or clothes dryer becomes overheated, it’ll simply shut off. That can prevent a fire and may be part of the reason there’s been a 55% drop in fires since 1980.
How to Troubleshoot Bimetal Thermostats
Troubleshooting this kind of thermostat is simple. Simply expose it to heat and see if it reacts.
You can use a heat gun if you have one. If you don’t, a hair dryer will work well too. Point it at the coil and see if the strip or coil changes shape.
If you don’t see much change, it may be that the strip or coil is worn out. It may have what is known as “thermal fatigue.” That’s the degradation of metal after a number of cycles of heating and cooling.
Drawbacks of Bimetal Thermostats
There are a few drawbacks you should be aware of. First, these thermostats are more sensitive to hot temperatures than cold ones. If you need to detect changes in lower temperatures, it might not be the way to go.
Second, a thermostat like this only has a lifespan of about 10 years. There may be more durable options, depending on the job.
Calco has a wide range of options for thermal regulation, no matter what your project is.
Shop Calco Electric’s Selection of Bimetal Thermostats
We have a wide range of bimetal thermostats for all your needs. There are cost-effective ones that can keep your project affordable and ones that can handle higher temperatures up to 400C.
Take a look at what we have to offer!