With thermal fuses you´ll make a big step towards a higher safety of your device.
It´s surely not necessary to remind that any device can fail. Failure of a component, overload of a component (underestimated sizing), external influence and many other reasons are daily causing failures of devices. If the result of a malfunction is only an intermediate shutdown, it´s let´s say a better case. But if a device malfunction could cause further damage or even fire, it´s surely worth to make everything possible to prevent it.
A typical component used as a complementary – independent protection from overheating is a thermal fuse. It is a cheap but very useful component, which opens (disconnects) a circuit after exceeding certain temperature. It is a “one shot” component, i.e. after its activation it remains open and the fused circuit is disconnected (the fuse must be exchanged). It´s suitable to choose such fusing temperature of the fuse, as we consider to be really faulty, which otherwise can´t occur in an ordinary operation. Production processes enable to produce thermal fuses in a wide range of temperatures and so fuses Microtemp from company Thermodisc, which we keep in stock, are available in a range of 72-257°C (opening temperature). It´s a really wide range enabling to use a fuse for example for fusing of other component (for example a thermal fuse thermally joined with a transistor heatsink) but also for guarding an air temperature inside a device. These fuses operate on a principle of melting a small plastic pellet inside a fuse, what will cause release of a spring and a consequent disconnection of contacts.
A substantial advantage of thermal fuses Thermodisc is a maximum current up to 10-25A/250VAC depending on a type. On stock we keep the G4 series with a max. current of 10A/250VAC. Small dimensions enable to use a component similarly like any ordinary component. It´s only necessary to be careful at assembling (overheating) especially at low-temperature types.
Details regarding a correct assembly as well as an overview and tips for a correct use of thermal fuses can be find in the Thermodisc application guide. Teplotné poistky sú dostupné aj v iných púzdrach, prípadne aj s nožovými kontaktmi (Fast-on). Thermal fuses are also available in other packages, or also with tabs (Fast-in). Finally, we can mention, that to reach the highest protection level in critical application, it´s ideal to incorporate several types with a slightly different fusing temperature in series.
They act only ones – right then, when it´s really necessary – [Link]