As the world has moved towards sustainable energy sources over the last few years, it’s increasingly common to be close to a wind turbine. The huge turbines visible on the horizon from where this is being written are the upper end of the scale though, and along comes [Robert Murray Smith] with the opposite, probably the simplest and smallest wind turbine we’ve seen.
His use of a 3-phase motor from a CD-ROM drive as the generator isn’t particularly unexpected, these motors are ubiquitous and readily generate power when spun up. A simple 3-phase rectifier and a capacitor delivers a DC voltage that while the ready availability of switching converter modules should be relatively easy to turn into something more useful.
The clever part of this hack lies then in the rotor, it’s not the propeller-style bladed affair you might expect. Instead he takes a CD, as it’s the obvious thing to fit on a CD motor, and glues a piece of Tyvek on top of it. This is cut to form four flaps which make a rudimentary but effective turbine when the wind comes from the side. It’s beautifully simple, and we wish we’d thought of it ourselves. The whole thing is in the video below the break, so take a look.
Maybe this won’t solve the green energy requirement on its own, but we’ve shown you far larger fabric turbines in the past.
Really useful info. Please send us some more on wind power.
You could do it with even fewer moving parts by having something flap in the breeze; like the inverse of this: https://hackaday.com/2022/08/23/flapping-pcb-fan-blows-a-little-bit/
How is a fewer moving parts going to be possible when this is basically down to 2, the rotor and the armature! If you look at it in the sense that both are permanently coupled, it is only 1 moving part ! There is no gear device between the 2 as there would be in a majority of commercial turbines of large scale. The only manufacturer of anything close to this would be Siemens which has designed and built a large scale turbine that is a direct drive as this is with no gear connection from the prop shaft to the alternator. The only other moving parts are the Yaw assembly which faces the props into the wind and a brake assembly to stop the turbine from running, which most likely requires moving the props out of the wind before engaging it ! Of course if you have to consider each piece of the armature or the actual power generating portion required to construct it instead of considering the full assembly as 1 moving part. The next most simple device isn’t a turbine but a solar panel with NO moving parts unless it is on a tracking system. On the topic of mechanically adapted devices to produce low level power, I’m still waiting to see the 2 inventions of the generator that fits on you knee and generates as you walk and the other that attaches to the frame of a backpack. I’ve read the knee device is capable of producing 12 watts with NO additional effort beyond normal walking and obviously the backpack device would be about the same outside of the added effort of carrying it. I heard the military has taken the device invention under consideration which may be the reason the public is not seeing it. I don’t know. I would still like to have a chance to see it and have access to them. These would be the ultimate in personal portable power for cell phones and radios, probably another reason the public has no access as far as I can find.
I assume that was supposed to be a reply to my post. TL;DR most of that stream of consciousness, but “moving parts” generally refers to parts that move /against/ another part; i.e. wear surfaces. The CD spindle has at least a bushing or two, and bearings in the higher-end versions. This would make at least 3-4 moving parts, and possibly a dozen or more. A compliant mechanism like the flapping coil has fatigue wear, but no frictional wear, unlike the motor spindle of the O.P.
There’s also the fact of the smaller cross-section, which would allow more to be packed into a given wind-facing area.
Remove the need for it to have a turbine and the simplest wind powered generator is 2 rows of wires, an electrostatic generator.
It’s both shocking and fascinating to see how cheap optical drives have become in the last few years.
When I compare their construction to the high quality construction of a ’92 SCSI CD-ROM drive or a ~2004 ATAPI DVD-ROM drive, I mean. Sure, there had been cheap top-loader designs from the very start, too, but what I saw in the video was on another (lower) level.
Oh, it’s this guy again…
The problem with the design is, you need to spin the DVD drive motor at several thousand RPM to generate anything. The nominal 1x speed of a DVD drive is about 600 – 1600 RPM and the motor is designed to go way way beyond that… so consequently it just won’t make you any voltage when turned at some few dozen RPM by flaps of paper.
The style of rectifier, and bias in the circuit can harvest appreciable power from any RPM. The limitations would be in amperage produced.
Maybe not ‘any’ RPM, but you know what I mean.
The typical DVD/CD drive motor is rated at 6 Volts for 3500 RPM. You have to turn it at least 500-800 RPM to overcome the rectifier forward voltage loss, before you start generating any useful power.
Assuming wind velocity of 6 m/s and a 12 cm DVD spinning along at that speed, you get 159 RPM. This thing would only start generating at 19 m/s wind speeds, that is, assuming the turbine keeps up.
Mind, the diode forward voltage loss depends on the forward current, so you CAN get something out if your only load on the circuit is a multi-meter or an oscilloscope.
Nevermind; I forgot to convert from seconds to minutes: 6 m/s -> 9,550 RPM
It could start generating at around 1 m/s.