quote:Yes, but the instructions at the web site MPH used, say to remove ALL the insulation from the wire. MPH did this, presuming it wouldn't work but it did -- hence the thread.
To be clear, he removed the insulation all the way around a small piece of the wire where it makes contact. The rest of the wire is insulated so the loops of the coil and the wrappings at each end are not actually creating shorts. The alternative (and more effective) construction method involves only removing the insulation from half of the wire in that small area.
Posts: 3275 | Registered: May 2007
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quote:Yes, but the instructions at the web site MPH used, say to remove ALL the insulation from the wire. MPH did this, presuming it wouldn't work but it did -- hence the thread.
To be clear, he removed the insulation all the way around a small piece of the wire where it makes contact. The rest of the wire is insulated so the loops of the coil and the wrappings at each end are not actually creating shorts. The alternative (and more effective) construction method involves only removing the insulation from half of the wire in that small area.
We will have to ask MPH to be sure, but the implication was that he removed all the way around the small piece of wire where it makes contact. He did not expect it to work this way but it did. We are looking for an explanation for why it would work at all this way.
Posts: 12591 | Registered: Jan 2000
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quote:We will have to ask MPH to be sure, but the implication was that he removed all the way around the small piece of wire where it makes contact. He did not expect it to work this way but it did. We are looking for an explanation for why it would work at all this way.
Right. I was just making sure that we were on the same page now. There was a point at which it seemed like some people were under the impression that the entire length of wire was uninsulated.
As for why it works when the entire circumference of the contact points are uninsulated, my guess is that because it's awfully difficult to get a perfectly straight hand-bend copper wire, you'll end up with some irregularities in how much contact each side gets while the coil is spinning. Assuming the coil is relatively balanced, it would only take a little bit of cyclic irregularity in the contact pattern to generate the same effect (albeit much weaker) as deliberately removing only half of the insulation.
Posts: 3275 | Registered: May 2007
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posted
So that's three different theories for how the thing works, all of which rest on some not-deliberately-introduced asymmetry of the system - extra-half-loop, parallel-resistor-distance, and now bent-wire asymmetries.
As a point of completeness, I note that a common explanation in this sort of general problem, where someone says "I've got this-and-that result and don't understand it, explain please", and a lot of theoretical effort is expended, is that the original poster is messing with the heads of the theorists. It may be the case that we should all have noticed our own confusion rather than spinning theories.
Posts: 10645 | Registered: Jul 2004
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quote:Originally posted by The Rabbit: Yes that occurred to me after I made the post. Sadly, I don't have a spool of magnet wire and an Ohm meter in my desk drawer to test it out.
Well, if you'd like I can see if I can take some time out to test it, as an Electrical Engineering student I have plenty of access to Ohmmeters.
Also, how did you calculate the effective resistance, because I ended up with the series resistance around 289 times that of parallel.
Posts: 2489 | Registered: Jan 2002
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Sadly, I don't have a spool of magnet wire and an Ohm meter in my desk drawer to test it out.
