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Old Hard Drives = Free Electricity
tylernt writes "You know all those old hard drives you have laying around? (Raise your hand if you still have RLL or MFM drives... yeah, I thought so.) Well, now there's something useful you can do with them (besides my personal favorite, shooting them): make electricity! While you're at it, you could do something more productive with that old lawnmower, too."
I know this is intended to to be funny but no, it can't. See the law of conservation of energy. You can't produce energy from a hard drive from mechanical means without energy change. You could try chemical change though. (burn it and use that to power mower).
Since when has this country used intellectual elite as a pejorative term?
clicky
occultae nullus est respectus musicae - originally a Greek proverb
Low RPM alternator tests with surplus hard drive magnets 9-13-99
.80" high, and .090" thick. They are nickel plated Neodymium Iron Boron magnets of impressive strength. I sell surplus magnets on my web site. In this test used some of my smaller ones, due to their seemingly unlimited supply.
In the effort to build my own low RPM alternator for small wind/water power applications, these are some of the tests I've performed and their results. First step is the magnets. I used surplus hard drive magnets which I salvaged from scrap computer hard drives. These magnets 1.4" long,
Next wound a coil from 23 gauge magnet wire. The coil is slightly under 2" long, and consists of 700 windings, with taps at 100, 200, 400, and 700 windings. The core for the coil is made from 20 2" long segments of enameled coat hanger wire, super glued together. This should reduce inefficiencies due to eddy currents through the core. I believe annealing the wire segments would probably improve performance, but I skipped that step here. The spool on which the wire is wound are made from paper, poster board, and super glue. There are certainly better materials to use here, although paper and cardboard worked just fine. The alternator Im currently building will have spools made of phenolic sheet.
Next I took a gear, 5.5" diameter and placed two rings of surplus computer hard drive magnets on it. Each magnet has 2 poles on each face. 7 of these ones fit tightly together in a ring, having 14 poles. I placed two rings of magnets on the face of the gear, one ring containing 7 magnets(which fit together nicely), and the other ring containing 12 magnets(which don't fit as well). The inner ring of 7 magnets is a little over 3.5" diameter. The outer ring is a little over 5.5" diameter. I then placed the gear in a small metal lathe on which I performed tests at 3 different speeds.. I tapped the coil to a boring bar, so that I could adjust its position in relation to the two rings of magnets.
Next step was to turn it on, and test the different taps on the coil, at 3 different speeds. I used a 12 Volt, 5 watt light bulb as a load, and tested the voltage of each tap on the coil, at each speed, with, and without the load. The tests were done at 200, 400, and 600 RPM
IMPROVEMENTS?
There must be many improvements. I have no doubt a better iron core could be used. The length of the coil, I chose 2" off the top of my head, I doubt its perfect, but I'm using that because I am building an alternator that will employ two discs, each with a ring of magnets, on opposite sides of the coil. 2" seemed like a good distance. 23 guage wire was convenient, and seemed like a good starting point, though I have a feeling that fewer coils of thicker wire might work better. Stacking magnets? I didn't double up the magnets for fear of the lathe launching them like bullets off the gear. I'm sure that this would have a good effect though-but-it would add to the cost of an alternator. More coils-the coil is exactly big enough such that 7 of them could fit nicely in an alternator using the small ring of 7 magnets. At this point, seems to me like an alternator built with 7 coils hooked either in series or parrallel-(or a combination) would perform reasonably well at low rpm. I have no idea yet what the effect of adding a second spinning ring of magnets to the back side of the coil will be, but I'm sure it will be significant. Although already somewhat obsolete, (because of the base/bearing arrangement) you can see my current alternator project in the picture below. I intend to finish this one, and test the output. The next one will have a much improved bearing arrangement, larger discs, and more coils.
Unfortunately for you, you have either far weaker magnets or none at all (of this type) in your older drive.
I've harvested parts from lots of old computer equipment. Very old hard drives, like 10-30 mb drives, use stepper motor head drivers--like a floppy disc drive. Early voice-coil drives used large, but relatively weak, magnets. Newer ones use tiny, but incredibly strong magnets.
Jim
linkified
Of course, the hard thing, as in all electric generation, is getting the generator to spin, which isn't done with the hard drives.
...
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True; the article doesn't address the issue of spin, other than the author used a small metal lathe to bench-test the alternator.
It's not a ground-breaking invention, I'm sure this sort of thing has cropped up periodically over the decades in science fairs.
And the author is selling magnets online -- let's not overlook this motive (though I think it's reasonable and I might do the same).
But the article is engaging, and for those (such as myself) who don't know the details of building an alternator, it's a good introduction.
Furthermore, the author states, right at the top:
In the effort to build my own low RPM alternator for small wind/water power applications
It's this laudable motive that makes the article worth SlashDot's time. We are (on a good day, anyway) the successors to the Whole Earth Catalog
-kgj
RLL and MFM were both encodings used on ST506 interfaces. ST506 predated ESDI.
So, if you find any old ST506 drives, you'll find they were much bulkier per MB than your ESDI drives.
The IBM XT and AT used ST506.
Oh, and its "sheer", not "shear"
I try so hard not to be a pedant -- I really do. I've ignored this oh-so-common mistake oh-so-many times, but after that inane article (or, should I say artical?), I can't resist any more.
It's practicAL not practicLE!
Every time I see practicle, it takes several seconds for me to be sure the author isn't referring to some sort of new subatomic particle with practical applications. Sigh. Please stop!
everything in moderation
You want the alternator secrets? Here's one, with some of the best explanations I've seen yet...
Secrets and Alternators..
-Phyre
"When the people fear their government, there is tyranny; when the government fears the people, there is liberty." -Thom
www.sunhelp.org - Contact this guy. He or someone on the mailing lists there should be able to find Sun 2 stuff for you.
"Bah!" - Dogbert
For those of you NOT following events in NZ, we're facing severe power shortages this winter.
Down here we've not built any new power plants for many years, we've just had a severe drought over summer causing our hydro lakes to be nearly empty, and just to top things off our largest natural gas field has just started running out - several years earlier than expected.
We've been asked to save 10% power, or we'll likely face brownouts, just as it gets freezing cold here. Yaaaaay.
pass me the sheep.
Do you know this guy? I don't know why spontaneously exploding food is so funny, but it is.
I believe you would be referring to a penetrator round, in the black or green tip.
.50 BMG caliber, to Explosive Ordinance Disposal folks to clear mines and other ordinance from a distance (by inducing deflagration of the explosive contents of said ordinance). Incendiary rounds are distinctly different from armor-piercing (AP) rounds, and are likely to be less effective on hardened targets, at least as compared to AP.
Incendiary rounds (sometimes referred to as explosive rounds) are generally used to detonate/set fire to something, and contain a core of some energentic, explosive substance (eg. fulminated mercury). The US military issues such rounds, in the
To penetrate any substantial thickness of steel, a higher velocity round is typically required... preferably with a hardened steel penetrator at the core of the projectile. Note, however, that an AP round is not always required... a standard jacketed round of sufficient velocity will sometimes cause failure of the barrier steel through a phenomenon known as "plugging," but a hardened steel core greatly increases penetration. As a side note, armor piercing "teflon" bullets are not aided in their armor-piercing ability by their teflon coating... they are AP because of the hardened steel projectile, NOT because of the teflon. The teflon coating on such rounds acts as a barrel lubricant, and is designed to prevent the hardened steel projectile from damaging the rifling (land and grooves) inside the barrel. A standard steel-core AP round has a soft lead jacket around the steel core, obviating the need for a teflon coating.
Depending on the composition of the steel, 3/8" may well resist an incendiary 5.56 NATO round.
Just my ballistic $.02
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
I just logged in here for the 1st time ever. Someone posted about this webpage I made years ago (almost 4 years) here on this.... seemingly busy discussion forum! (and we had to bolt our server down!!!) This page is obsolete, I'll try to find the time to update it today. My new experiments with "homebrew electricity" are located at otherpower.com. Ive read a few of the comments and it seems many were thinking that alternator was a perpetual motion experiment. It was NOT!!! - the idea was wind power all along. But the alternator was impractical and ... even more badly designed than my more recent ones! (My more recent ones are very simple, but reasonably powerful and somewhat effficient considering their simplicity I think.
The problems with that alternator were many...
The coils were too long, and the flux from the thin magnets through the long coils was very weak, meaning more wire and high resistance.
It was basicly too small to create useful qty's of electricity.
The steel cores in the coils (there were 7) lined up perfectly with the the 14 poles in the magnetic rotors, so the machine cogged very badly - the blade for a small wind turbine could've never started. This also caused severe vibration.
The plexiglass stator was not nearly strong, or heat resistant enough.
Those were the main things...
Although I think hard drive magnets could surely be used in this application, the alternator design is poor.... I do many things differently now. Again - my later efforts are on in the "experiments" section at otherpower.com.
More recent, simpler, and
So let me get this straight. You're going to take one of the most polluting combustion engines, and convert it into a 24-hour operating generator. Lawnmowers don't have anywhere near the filters that larger engines do and no catalytic converters to reduce emissions.
"In the Swedish testing, the researchers used regular unleaded fuel in a typical four-stroke, four horsepower lawn mower engine and found, after one hour, that the PAH emissions are similar to a modern gasoline-powered car driving approximately 150 kilometers (93 miles). A typical push-type lawn mower is run for an average of 25 hours per year, according to the Outdoor Power Equipment Institute."
So, running a lawnmower engine for 1 day is equivalent to the pollution put out by your average car in 2200 miles, about 2 months worth of standard driving.
Stronger magnets produce more power. Physically, a stronger magnetic field will lead to a greater voltage at the same current. But, you could cut the number of turns on the coil in half, get the same voltage as before, but twice the current. The product of voltage and current is power*, and that's what is increased by a stronger magnet. For example, say you get 20 volts, 10 amps from a 500-turn coil. You now double the magnet strength and get 40 volts, 10 amps. Now, cut the coil down to 250 turns, and you get the original 20 volts, but now 20 amps.
*Since the current is alternating, we're really talking about the dot product of voltage and current. I say this to stave off the inevitable "correction" someone will make.