[John] and [Matthew] built an induction-heater based furnace and used it to make tasty molten aluminum cupcakes in the kitchen. Why induction heating? Because it’s energy efficient and doesn’t make smoke like a fuel-based furnace. Why melt aluminum in the kitchen? We’re guessing they did it just because they could. And of course a video, below the break, documents their first pour.
Now don’t be mislead by the partly low-tech approach being taken here. Despite being cast in a large KFC bucket, the mini-foundry is well put together, and the writeup of exactly how it was built is appreciated. The DIY induction heater is also serious business, and it’s being monitored for temperature and airflow across the case’s heatsinks. This is a darn good thing, because the combination of high voltage and high heat demands a bit of respect.
Anyway, we spent quite a while digging through [John]’s website. There’s a lot of good information to be had if you’re interested in induction heaters. Nonetheless, we’ll be doing our metal casting in the back yard.
Continue reading “Kentucky-Fried Induction Furnace”
[Diato556] made a really cool single-phase induction motor with parts mounted on Duplo blocks. He has posted an Instructable where he uses these modular parts to demonstrate the motor and the principles of induction as described after the jump.
Continue reading “LEGO® My Single-Phase Induction Motor”
When his 6 years old induction cooker recently broke, [Johannes] decided to open it in an attempt to give it another life. Not only did he succeed, but he also added Bluetooth connectivity to the cooker. The repair part was actually pretty straight forward, as in most cases the IGBTs and rectifiers are the first components to break due to stress imposed on them. Following advice from a Swedish forum, [Johannes] just had to measure the resistance of these components to discover that the broken ones were behaving like open circuits.
He then started to reverse engineer the boards present in the cooker, more particularly the link between the ‘keyboards’ and the main microcontroller (an ATMEGA32L) in charge of commanding the power boards. With a Bus Pirate, [Johannes] had a look at the UART protocol that was used but it seems it was a bit too complex. He then opted for an IOIO and a few transistors to emulate key presses, allowing him to use his phone to control the cooker (via USB or BT). While he was at it, he even added a temperature sensor.
If you’ve ever wanted to forge, cast, or smelt metal, this project is right up your alley. It’s a 30 kVA induction heater built by [bwang] over on Instructables. It gets hot enough to melt and forge steel, iron, and aluminum.
An induction heater operates by surrounding the object to be heated with a coil carrying high frequency AC current. Basically, the entire setup acts like a huge transformer with a shorted secondary. To get these currents into a workpiece, [bwang] used a TL494 PWM controller as an oscillator. The output of the TL494 is filtered and amplified a few times to generate a huge amount of AC current.
Larger versions of [bwang]’s induction heater are found in foundries and forges all across the land; even though this small version sucks down 50 A out of a dryer or stove outlet, induction heating is very efficient. We’re actually wondering why we don’t see many home blacksmiths using induction heating, so we’ll leave that for our readers to discuss in the comments.
[sessions] reminded us of this induction heater from a few years ago. A little smaller, but still usable.
For those of you not familiar, an induction heater is a device capable of heating something up very rapidly using a changing magnetic field. [RMC Cybernetics] decided to build one and was nice enough to write up the project for the Internet’s learning and amusement. A full explanation as well as a schematic and build instructions are provided on their website.
This heater works using a principle involved in most transformers. When there is a change in the magnetic field near a conductive object, a current will be induced in it and it will generate heat. Interestingly enough, while transformers are designed to minimize this heat, an induction heater instead aims to maximize this heat in whatever object is placed within the coils.
[RMC] Has provided a video of how to build the heater as well as it in action after the break! Skip to to 1:42 to see the heating in action. Or watch the whole thing to see how it’s built.
Continue reading “A Simple Induction Heater”
This is a custom back plate with induction charging circuitry that [Derek Hughes] build for his HTC HD2 cellphone. When we checked in with him last week he showed us how to add an inductive charger without voiding the warranty but it wasn’t very pretty because the stock back plate blocked the inductive field and couldn’t be used. The solution he came up with will work with any device if you want to put some time into the build.
He took two different aftermarket cases; one fits his cellphone and the other is a BlackBerry case meant for housing a credit card. After cutting a hole in the back of the cellphone case he epoxied the credit card holder in place, smoothed the seam with Bondo, and repainted. Not only does the charger fit in the credit card case, but there’s still room for a credit card. [Derek] also measured the magnetic fields around the circuitry and found they will not damage the magnetic strip on that American Express Black you’ve been keeping on you. In the video after the break he mentions the last step in finishing this case will be to locate a 90-degree USB plug as the current connector is a bit of an eyesore.
[Tyler LaVite] tipped us off about the generator he built. He combined a 5.5 horsepower Honda motor with a 10 horsepower electric bandsaw motor. To get an induction generator to produce alternating current you must feed electricity into the system to start the magnetic flux. [Tyler’s] solution was to include a bank of capacitors totaling 230mF which charge from the motor, then release back into the system. It’s not as green as the syngas generators we’ve seen since it still uses fossil fuel, but it reuses old parts sending less to the landfill.