‘Upgrading’ A Microwave Oven To 20 KW

October 25, 2024 by Dave Rowntree 38 Comments

Whilst microwave plasmas are nothing new around here, we were curious to see what happens at 20x the power, and since YouTuber [Styropyro] had put out a new video, we couldn’t resist seeing where this was going. Clearly, as your bog standard microwave oven can only handle at most one kilowatt; the ‘oven’ needed a bit of an upgrade.

A 16 kW water-cooled magnetron. Why not over-drive it to 20 kW for fun?

Getting hold of bigger magnetrons is tricky, but as luck — or perhaps fate — would have it, a 16 kW, water-cooled beast became available on eBay thanks to a tip from a Discord user. It was odd but perhaps not surprising that this Hitatch H0915 magnetron was being sold as a ‘heat exchanger.’

[Styropyro] doesn’t go into much detail on how to supply the anode with its specified 16 kW at 9.5 kVDC, but the usual sketchy (well down-right terrifying) transformers in the background indicate that he had just what was needed kicking around the ‘shop. Obviously, since this is a [Styropyro] video, these sorts of practical things have been discussed before, so there is no need to waste precious time and get right on to blowing stuff up!

Some classic microwave tricks are shown, like boiling water in five seconds, cooking pickles (they really do scream at 20 kW) and the grape-induced plasma-in-a-jar. It was quite clear that at this power level, containing that angry-looking plasma was quite a challenge. If it was permitted to leak out for only a few seconds, it destroyed the mica waveguide cover and risked coupling into the magnetron and frying it. Many experiments followed, a lot of which seemed to involve the production of toxic brown-colored nitrogen dioxide fumes. It was definitely good to see him wearing a respirator for this reason alone!

Is it purple or is it indigo? Beauty is in the eye of the beholder!

The main star of the demonstration was the plasma-induced emissions of various metal elements, with the rare indigo and violet colors making an appearance once the right blend of materials was introduced into the glassware. Talking of glassware, we reckon he got through a whole kitchen’s worth. We lost count of the number of exploded beakers and smashed plates. Anyway, plasma science is fun science, but obviously, please don’t try any of this at home!

For those who didn’t take an ‘electron devices’ course at college, here’s a quick guide to how magnetrons work. Plasma physics is weird; here’s how the plasma grape experiment works. Finally, this old hack is a truly terrible idea. Really don’t do this.

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Nine men of various ages and ethnicities stand in a very clean laboratory space. A number of large white cabinets with displays are on the left behind some white boards and there are wireless charging coils on a dark tablecloth in the foreground. In the back of the lab is a white Porsche Taycan.

Polyphase Wireless EV Fast Charging Moves Forward

June 21, 2024 by Navarre Bartz 80 Comments

While EV charging isn’t that tedious with a cable, for quick trips, being able to just park and have your car automatically charge would be more convenient. Researchers from Oak Ridge National Lab (ORNL) and VW have moved high-speed wireless EV charging one step closer to reality.

We’ve seen fast wireless EV chargers before, but what sets this system apart is the coil size (~0.2 m² vs 2.0 m²) and the fact it was demonstrated on a functioning EV where previous attempts have been on the bench. According to the researchers, this was the first wireless transfer to a light duty vehicle at 270 kW. Industry standards currently only cover systems up to 20 kW.

The system uses a pair of polyphase electromagnetic coupling coils about 50 cm (19″) wide to transfer the power over a gap of approximately 13 cm (5″). Efficiency is stated at 95%, and that 270 kW would get most EVs capable of those charge rates a 50% bump in charge over ten minutes (assuming you’re in the lower part of your battery capacity where full speeds are available).

We’ve seen some in-road prototypes of wireless charging as well as some other interesting en route chargers like pantographs and slot car roads. We’ve got you covered if you’re wondering what the deal is with all those different plugs that EVs have too.

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Hackaday Prize 2023: 10 KW Electronic Load

September 1, 2023 by Dave Rowntree 22 Comments

[tinfever] needed a high-power benchtop electronic load for an upcoming project, and by their own admission decided foolishly to build their own. And we’re glad they did. The thing is, whilst this isn’t exactly a super-cheap project to build, buying a commercial offering with a capability of 10 kW and up to 30 kW pulsed, is going to cost an absolute fortune.

Built inside a cubic frame using what appears to be standard 2020 aluminum rails and fixturing, the modular construction is nice and clean, with plenty of space around the load boards to allow the cooling air to circulate.

The operating principle is very simple; custom PCBs act in parallel to provide any load needed, by switching in the on-board load resistor. Each load board handles all the details of switching and dumping the power due to the inductance in the system wiring and the wire-wound resistors themselves.

Whilst we know that wire-wound resistors are reverse-wound to minimize inductance, there will still be some, and each load board will contribute a little more when the whole system is scaled up. Also, each load PCB handles its own temperature sensing, and current measurement passing these data off to the control PCB. A front-end connector PCB provides a variety of connection options to interface to the DUT (Device Under Test.) The system controller is based around an STM32 processor which deals with quite a lot more than you might think is needed on a first look.

The sense currents from each load need to be sensed, scaled, and summed to keep the overall load accuracy within the 1% spec. Also, it is on duty for PWM control of the cooling fans, handling the user interface, and any other remote connectivity. There are a lot of details on the project page, as we’re only skimming the surface here. If you’re interested in building an active load, this is a project you really should be digging into.

We shall watch with interest for when [tinfever] scales up this eight-slot prototype to the full specification of 52 stages! When working with power applications, there comes a point when you really need an electronic load, and to that end, here’s one with a very specific use case to get you started.

There is also the option of buying something cheap from the usual sources and hacking on some custom firmware to adapt it a little to your needs.

Wireless Charging On A Massive Scale

March 21, 2023 by Bryan Cockfield 26 Comments

Despite the increasing popularity of various electric vehicles, the limits of battery technology continue to be a bottleneck in their day-to-day use. They don’t behave well in extreme temperatures, they can wear out quickly, and, perhaps most obviously, charging them is often burdensome. Larger batteries take longer to charge, and this can take a lot of time and space, but this research team from Chalmers University are looking to make this process just a little bit easier.

The group has been developing an inductive wireless charging method for large vehicles including cars, trucks, busses, and ferries that can deliver 500 kW across a 15 cm (6 inch) air gap. The system relies on a silicon carbide semiconductor and extremely thin copper wire in order to make all this happen, and eliminates the need for any human involvement in the charging process. This might not be too much of a hassle for plugging in an electric car, but for larger vehicles like busses and ferries traditional charging methods often require a robot arm or human to attach the charging cables.

While this technology won’t decrease the amount of time it takes batteries to charge, it will improve the usability of devices like these. Even for cars, this could mean simply pulling into a parking space and getting the car’s battery topped off automatically. For all the talk about charging times of batteries, there is another problem looming which is that plenty of charging methods are proprietary as well. This charger attempts to develop an open-source standard instead.

Thanks to [Ben] for the tip!

Bad Thermal Design And Burning Down The House

March 25, 2017 by Brian Benchoff 31 Comments

Control boards for 3D printers are a dime a dozen on the usual online marketplaces, and you usually get what you pay for. These boards can burn down your house thanks to a few terrible design choices. [Scott Rider] aka [Crow] took a look at the popular Melzi board, and what he found was horrifying. These boards overheat right at the connector for the heated bed, but the good news is these problems are easily fixed.

The Melzi board has a few problems with its PCB design. The first and most glaring issue is the use of thermals on the pads for the heated bed connector. In low-power applications, thermals — the method of not connecting the entire top or bottom layer to a hole or pad — are a great idea. It makes it easier to solder, because heat isn’t transmitted as easily to the entire copper layer. Unfortunately, this means heat isn’t transmitted as easily to the entire copper layer. In high-power applications, like a connection to a heated bed, these thermals can heat up enough to melt a plastic connector. Once that happens, it’s game over.

Other problems were found in the Melzi board, although you wouldn’t know it just by looking at the Eagle file of the PCB. [Scott]’s Chinesium Melzi board used 1-ounce copper, where 2-ounce copper would be more appropriate. The connector, too, should be rated above the design power loading.

[Scott] made a few tweaks to the board and also added a tiny DS1822Z temperature sensor to the high-current area of his version of a Melzi. Imagine that, 3D printer electronics with a temperature sensor. Slowly but surely, the state of 3D printer electronics is clawing its way to the present.

20kW Light Is As Bright As You’d Expect

July 28, 2016 by Gerrit Coetzee 37 Comments

[Photonicinduction] purchased a very very bright light. This 20,000 Watt half meter tall halogen will just about light the back of a person’s skull with their eyes closed. These are typically used to light film sets.

Most people couldn’t even turn such a light on, but [Photonicinduction] is a mad scientist. Making lightning in his attic, it’s easy to mentally picture him as the villain in a Sherlock Holmes novel. Luckily for us, if he has any evil tendencies, they are channeled into YouTube videos.

He gives a good description of the mechanical and electrical properties of the light. The body is as one would expect for an incandescent light. A glass filament envelope with the filaments supported within. The envelope is evacuated and filled with an appropriate gas. This light is dangerous enough that the outside must be thoroughly cleaned of fingerprints to keep a hot-spot from forming, which could cause the lamp to explode.

After some work, he managed to convince himself that the filaments within were not, in fact, garage door springs, and gave a demonstration of their properties. For example, their resistance goes up as they are heated. In order to keep from tripping the power supply, filaments this large must be preheated. Failure to do so passes a very large number of amps.

The next step was to hook the lamp up to his home-made 20 kW power supply. He gives a good demonstration of just how bright it is. Within seconds he’s sweating from the heat and definitely can’t even open his eyes to see with the tiny sun occupying the center of his abode. Video after the break.

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Hacklet 92 – Workbenches And Toolboxes

January 23, 2016 by Adam Fabio 3 Comments

Everyone needs a place to work. While some of us have well equipped labs with soldering stations, oscilloscopes, and a myriad of other tools, others perform their hacks on the kitchen table. Still, some hackers have to be on the go – taking their tools and work space along with them on the road. This week’s Hacklet is all about the best toolbox and workbench projects on Hackaday.io!

We start at the top – in this case, a bench top. [KickSucker] created Mondrian Inspired Work Table as a multi-use tabletop for all kinds of projects. Rather than slap down a piece of plywood, [KickSucker] took a more artistic route. Piet Mondrian was a dutch artist known for painting irregular grids of black and white lines. He’d fill a few of the rectangles up with primary colors, but leave most of them white. Between different off-cuts of wood, and colorful bits of skateboard deck [KickSucker] had the makings of an awesome work surface. The frame of the bench is an IKEA expedite shelf unit. The frame is made from MDF, with the offcuts laid on top of it. The fun part was arranging all the pieces to make lines and colors. The result is a great custom work table, and a heck of a lot less wood scraps lying around the shop. That’s a double win in our book!

Next up is [M.Hehr] with Portable Workbench & mini Lab. [M.Hehr] has wanted a portable electronic workstation for years. We’re betting he’s seen a few of them here on the blog. While cleaning up the lab before Christmas, [M.Hehr] found a couple of wooden IKEA boxes. Each box held some drawers. An idea formed in [M.Hehr’s] head. It was time to put the plan in motion! The boxes were attached and hinged. Custom brackets were cut on a Shapeoko 2 router. Everything – even the screws were recycled. [M.Hehr] created a perfect space for each tool, ensuring that things won’t end up in a tangled mess when the box is carried around. We really love the retractable power point and custom-made power supply!

Next we’ve got [Tim Trzepacz] with Musician’s Road Box with 9 space rack. [Tim’s] sister [Tina] was playing a lot of music on the road, and needed a way to organize her gear. There are plenty of commercial solutions for this, but [Tim] decided to roll the perfect solution. He designed a plywood box with a 9U rack. [Tina’s] mixer and backing sound sources were located on the top, while effects and other modules were located in the rack. [Tim] spent a good amount of time designing the box. He was able to get the cut list down to a single piece of plywood, with room to spare. This is perfect for a 4′ x 8′ router like the ShopBot. When it comes time to hit the road, the case seals up to a rugged package. Standard roadcase corners and twist-latches finish this awesome piece.

Finally we have [Géllo] with protoBox. [Géllo] is into induction heating, which requires a Zero Voltage Switching (ZVS) flyback driver. ProtoBox started life as a place for [Géllo] to store his ZVS. It has evolved to become a small portable electronics lab. [Géllo] powers the box with a set of lithium-ion batteries sourced from old laptops. This particular ZVS design is plenty powerful enough to heat metal red hot, or create some nice arcs. [Géllo] added an Arduino Mega, a Bluetooth radio, and a 2×16 character LCD. The system is controlled with relays. A bluetooth enabled smartphone can be used to enable or disable any feature. [Géllo’s] assembly techniques are a bit scary, especially considering the fact that this is a high power design. However, this is a great proof of concept!

If you want to see more workbench and toolbox projects, check out our new workbench and toolbox list! If I missed your project, don’t be shy! Just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!