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. 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]
Jack Shandle writes:
LED-based lighting has many advantages including a small footprint, exceptionally long lifetimes and excellent lighting efficacy in lumens per watt. As LEDs have become popular, the challenges of designing with them have become more evident – with thermal management topping the list.
The challenge begins with the source itself. High-powered LEDs do not generate infrared radiation, which is the primary way competing light sources dissipate energy that is not visible light. Instead, 75 to 85 percent of energy used to drive an LED is converted to heat, compared to 42 percent for a typical linear fluorescent, 37 percent for a metal halide bulb, and only 19 percent for an incandescent light source. In LED-based system designs, this heat must be conducted from the LED die to heat sinks, the circuit board, housings or luminaires. In addition, power dissipation in other parts of the system, such as the power supply, must be minimized.
ABCs of LED Thermal Management - [Link]
As consumer devices continue to shrink in size, power considerations and appropriate thermal design become increasingly important for circuit designers and board layout engineers. This tutorial helps designers to ensure that a board is both electrically sound and thermally balanced for proper operation and optimum efficiency.
Layout Considerations for High-Power Circuits - [Link]
Power plants and many industrial processes produce heat as a byproduct, as much as up to 50% of the initial energy input may be released as heat. What if we could store this waste heat for later use?
The most common form of thermal storage is in insulated water tanks, but water can only retain heat for a short period of time as it cools off gradually. Zeolite is a mineral that can store up to four times more heat than water can, but, unlike water, zeolite retains all of the heat for an unlimited period of time. Although these unique properties of zeolite are well known, it is only now that scientists of the German Fraunhofer Institute have succeeded in using the mineral to build a working thermal storage system. [via]
Store Thermal Energy Forever - [Link]
Mini Thermal Receipt Printer – [via]
Add a mini printer to any microcontroller project with this very cute thermal printer. Thermal printers are also known as receipt printers, they’re what you get when you go to the ATM or grocery store. Now you can embed a little printer of your own into an enclosure. This printer is ideal for interfacing with a microcontroller, you simply need a 3.3V-5V TTL serial output from your microcontroller to print text, barcodes, bitmap graphics, even a QR code!
Mini Thermal Receipt Printer - [Link]
Get your tweets in now, the Thermal Tweeter live stream will end later this week. Send a tweet to @dangerousproto and watch it print out live on the USTREAM feed.
The Thermal Tweeter is sitting in the photo studio, and we need it back to document a few new projects. Judging for the Adafruit Make It Tweet Challenge ends July 5th, and the live stream will come down shortly after
Last chance to print your tweets @dangerousproto – [Link]
One of the first things we heard when we started talking to firefighters about the potential for a heads-up display was “give us more and cheaper access to thermal imaging.” Being the tinkerers that we are, we thought we’d try to cobble something together with an Arduino and some off-the-shelf sensors. Luckily, some other folks in the Arduino community forged the way, so we didn’t have to start from scratch. Our thanks to Stephan Martin for his original write-up detailing his thermoscanner.
DIY Thermal Imaging System for under $200 - [Link]
The ultimate tools for troubleshooting and maintenance. [via]
This thermal Imager is the perfect tool to add to your problem solving arsenal. Built for tough work environments, this high-performance, fully radiometric infrared camera is ideal for troubleshooting electrical installations, electro-mechanical equipment, process equipment, HVAC/R equipment and others.
Handheld thermal imager - [Link]