Step 7: Common Configuration

By far the configuration that I see the most is the "Common" configuration (fig. 1). I call it common configuration because each coil has one end free and the other connected to a common wire (to which all other coils are connected too).

This configuration is by far the easiest configuration to use. No extra work is required, all we need to do is work out which wire is which.

There will be one wire that upon closer inspection is many wires soldered together. This is the centre tap. Pick any other two wires. You now have your two "ends". In figure two we are simply ignoring the "red" coil, you may ignore more or none - the number of coils on a "common" configuration varies, I have seen two and three coils, but I see no reason why there couldn't be more.

That's all that you need to do for this step, so keeping track of which wire is which, jump to the "Time To Test" step.
What would make this any better than if I just unwound the coils and made a joule thief that way?
<p>N1ce Concept of using Motor winding as Trafo. But does the core is designed for high frequency?? I tried with couple of torroid but they failed when used with Mosfet under High frequency.</p><p>Oh The design outcome is awsome.</p>
All right Andy here's the comment you suggested that I should post, slitely defferent though because I felt I should share more info on the subject of joule thief's. The efficiency of the joule thief could be improved by winding your own coils it's time consuming and a pain in the but to remove the existing coils but I find winding my own coils often yields good results. I made a transformer the size of a penny and got 18 volts dc from a 1.5 volt AA battery and that was just by connecting and disconnecting it to the battery by hand, it is a pain but making your own coils is worth it.
Very interesting idea for a joule thief. Good for recycling old motors (like case fans)
Hi,<br><br>The range of stepper motors in even one computer (floppy (2 motors), CD drive (2 motors), Hard drive, case fan, CPU fan, power supply fan) is quite surprising, it was due to having an over abundance of old computers' mismatched motors that I became interested in reusing them for something.<br><br>My favourite stator is found in laptop CD drives - it is a small, flat pancake stepper that works very well with the joule thief circuit, and makes a compact and very flower like device.<br><br>With regard to your other comments, thanks for the terminology corrections. As previously noted I have been unable to find any consensus on the names of the variously structured stepper motors - I just made some names up because in this instructable they only serve as points of reference to aid hacking. I do appreciate terminological corrections and think that they are useful as comments. <br><br>One thing to note is that comments don't attach to a single step, only to the instructable. It's clear from your messages what you mean, but just for future reference that's how Instructables lists comments (that confused me a few times when I joined too).<br><br>Thanks,<br>Andy
actually they do attach to steps, but they are all listed as one on the first page. if you click the delta page only my comment will show up!
Ha..I had no idea!<br><br>Thanks again,<br>Drew
I believe this is known as delta (hence the triangle shape)
Note I posted this on the &quot;Ring Configuration&quot; page
I believe this is called Wye (where it looks like a Y)
Note I posted this on the &quot;Common Configuration&quot; page
That floppy drive stator when built to catch and turn with the wind will produce electricity. <br>I am looking for more disk drives to do just that but they are kind of hard to find in Hawai'i cause everyone has the latest of everything here it makes me sick. <br> <br>When I find the next drive I will take the thing apart more carefully. The screw that holds the disk that holds the magnets has Lefthand Threds. Hindsight is 20/20. <br> <br>I will be very interested to know when the strip magnet is replaced with more powerful tiny magnets from harddisk drives, how much electricity I can harvest from such a tiny stator. <br> <br>
As far as I know, any magnet based stepper motor will be capable of producing electricity when rotated. The trick is working out the wiring and applying rectifying and smoothing circuits.<br> <br> If your looking for a small generator there are many alternatives to floppy disk drives - anything broken with motor actuated parts (personally I have reused motors from toys(dc), motors from printers, scanners, record players, walkmans, tape players, CD and DVD drives, servos and many others). Hard drive disk motors are very well made and well worth scavenging. If you find <em>anything</em> broken and electrical it is rewarding to take apart, if for nothing else than to see how it works, and how it's made.<br> <br> I too have come across counter intuitive things like &quot;backwards&quot; threads and 3 spoke Philips heads, and other puzzling design decisions. The hardest dis-assembly that I have done was a (broken) office laser printer, which had multiple concealed redundant retaining clips and screws.<br> <br> I have wanted for a while to make a mini portable generator, possibly a VAWT (Vertical Axis Wind Turbine) and it's low down (getting higher) on my &quot;future projects&quot; list.<br> <br> Regards,<br> Drew<br>
This does look like a really good way to build a joule thief. Just a note on terminology, it does vary, but the &quot;Ring&quot; configuration you mention, is also called &quot;Delta&quot; and what you refer to as &quot;Common&quot; may also be called &quot;Star&quot; configuration.
Hi,<br>Thanks! Yeah I had trouble with the terminology, in that I found lots of names for different connection graphs. In the end I just made up some names for the various topologies based on how they look - I figured that it would be easier to understand if I just gave each a name and stuck with it.<br><br>Thanks for your input,<br>Drew
<br> Easier to wind than a toroid, nice post.<br> <br> L<br>
PNP 2N3904??? The 2N3906 is the PNP version. I think you meant NPN. But it would be brighter if a 2N4401 or PN2222A were used.<br><br>Other shielded wire?? I think you meant insulated wire.
Thanks for the corrections and recommendation acmefixer, I have changed the errors on page one. I described using the 2N3904 simply because that's what I have to hand, and never got round to investigating alternatives.<br> <br> I think your right about swapping out the 2N3904 for something beefier, but I can't see having four transistors in parallel being very good looking, the problem of holding components in place becomes more of an issue if you are free forming. Having said that if it makes it work it makes it work.<br> <br> Thanks for your input,<br> Drew<br>
Interesting idea. (pretty. I've been staring at motor guts for a while trying to think of something functional to make with them.) I suspect it's inefficient because motor windings are designed NOT to magnetically interact with one another (as opposed to interacting with the rotor.) I wonder if one of the single-cell LED schemes that doesn't use a center-tapped inductor would work better. (like this <a href="http://electronicdesign.com/article/components/single-alkaline-battery-drives-white-led5886.aspx">Electronic Design article</a> )<br>
I was thinking something along the same lines... One of my &quot;queued&quot; projects is to try to run a Nixie tube off a particularly large stator (from a printer) using a bus pirate as the source of the PWM signal. I'm currently still doing things with my rotary screen but once I get round to it I'll report back here with my findings.<br> <br> Thanks,<br> Drew
A single winding coil circuit like the one in that link would work. But the 2N3904 is a weak little transistor with a chip that's half the size of the 2N4401 and is overworked in a Joule Thief circuit. It works but the light output is substantially lower. I just got a brainstorm. Put four - or maybe more - 2N3904s in parallel for even more visual impact. By the way, if builders are concerned about the battery life, they can increase the resistor to 3.3k or even more, to cut down on current - but with less light output. Or else use my <a href="http://watsonseblog.blogspot.com/2010/06/supercharged-joule-thief-flasher-rides.html">Supercharged Joule Thief Flasher</a> circuit.

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Bio: Andrew is a software engineer by trade and prefers projects that are simple yet effective. Andrew's areas of interest include software systems that do ... More »
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