Bedini School Girl Science Fair Motor discussion. This isn't for the versions that charge batteries. This is really for beginners who just want to learn more about the very simple roller skate version.

These 2 schematics are the best ones to start with to learn the Bedini circuits. Don't worry about energy recovery and charging batteries with them. Just build this to learn the prinicples of the monopole.





I didn't even know what a transistor was when I build my first one. When you looked at the circuit, it literally looked like the schematic. You don't have to spend a lot of money either. I used a pink roller skate wheel from a $2 pair of roller skates from the Goodwill.

thanx so much I never thought id get such a great welcome. Im going to try it, so I may not be posting much until i get it working
God bless

You'll probably get it working on the first try.

Use a 10ohm resistor to start with, easier to get it running on that. Not as efficient, but just get it to work.

1 X 10ohm resistor
1 X 1N914 diode
1 X MPS8099 transistor or RCA3055 or 2N3055 either of those will work fine

Get enough wire of #23 and #26 or closest you can find for those. Enamel coated magnet wire..enough to wind about 600 turns on the coil to the dimensions in those schematics. Make sure to wind it so that when you put + top the top of the coil and - at the bottom that the magnetic field on the coil is NORTH at the TOP. Wind both of those wires together at the SAME time around the spool.

The core for the coil can be a soild piece of iron or use a bunch of smaller pieces of welding rod cut to lenght and bundled together.

The transistor has a collector, emitter and base. The collector is the input, the emitter it the output. With these NPN transistors, there is no connection through the transistor from collector to emitter. The faucet is shut off basically. To make the connection, it requires a bit of current at the base...that is what the trigger wire is for. That turns it on and when the power is no longer at the base, the transistor shuts off. It is just an off and on switch triggered by the base.

When you buy the transistor, the package will give you a diagram or you can find it online which lead is what. BCE are the 3 you need to know. Just connect the coil wires, diode and resistor to each other like in the diagrams John drew.

The resistor doesn't matter which way you put it. The diode, the little black stripe needs to be towards the base of the transistor.

Make sure the wheel spins really, really easily. One little spin and it just keeps going. You can make it like mine where the wheel spins around the shaft or you can make it fixed to the shaft so the shaft spins in some bearings in the frame uprights.

You can use regular ceramic magnets on the rotor. Just make sure North is facing out on all 4 magnets so that south are all facing towards the axle.

The little black sealed gel cell batts are good ones to play with for starters. Use 12 volt ones.

When it is all hooked up, you give a slight little spin on the wheel and it will just start speeding up as fast as it can go.

When you get it running with these parts (use the 10ohm resistor), then you can switch out the resistor to something like a 680ohm to see if it will run on that. You basically want as much resistance as possible while still letting enough get through to trigger the transistor. That is the idea anyway.

There are a LOT of people around the world who have build these Bedini machines so you won't have a problem getting people to help you out.

A couple of questions what is enough wire?
and
What is Enamel coates magnetic wire? Is the wire magnetic?

That looks like three questions mea cupa

Hi Sykavy,

The enamel coated magnet wire is copper wire with a transparent coating of enamel. It comes in different thicknesses measured in guage like 23, 26, etc... the lower the number the fatter it is. The wire isn't magnetic but when wound into a coil and power is applied, it will turn into an electromagnet. The wire is insulated with the enamel so the wire dosn't short itself.

You want enough wire to wind 600 turns of both wires at the same time. 100-200 feet of each should be enough. Just wind the coil so that it fills out to the spool ends. Follow the dimensions of the coil in John's drawings. 100-200 feet doesn't cost that much and you can get at most electronic supply places in most towns. I buy wire by weight like 10 pound spools of whatever gauge...That is a lot more than you need, but shop around.




A couple of questions what is enough wire?
and
What is Enamel coates magnetic wire? Is the wire magnetic?

Thanks! I also don't know how to tell the north from the south on the magnets. Also when I wind the spool does it have to be a special material?

How do I know which end of the spool of wire is north? Should the winding be very tight?
PS: The first law of history is not to dare to utter falsehood; the second, not to fear to speak the truth

the radiant stuff is cool and i can understand some of it but it isnt really the basic stuff i thought this thread was about.

How do i know the difference between north and south pole on the magnet? Im not joking , i really dont know.

I made my SG according (i think) to the plans you gave me above but the coil gets very hot in a short time. Have i done something wrong?

Hi Sykavy, I apologize. I forgot to answer your question about the poles.

click the thumbnail picture below.

Yes, wrap the coil pretty tight and wrap both wires together...both the trigger and power wire together.

The thumbnail picture below (click it) shows how to wrap the coil so that when you put + at the top and - at the bottom, you will get a NORTH field at the top of the coil. As long as the wire at the top is coming off the coil towards you from around the right side and the bottom wire is coming off the coil towards you from around the left side and you put + and - as shown, you will get a NORTH field at the top.

I like to start with the wires coming off the bottom of the coil poking off from the left side pointing at me. Then, I wrap upwards and down up and down up and down and I try to end at the very top...that is just to prevent confusion, you could of course end them both at the top and both at the bottom, but this makes it simple.

If you wind the coil like that you get the north field when a battery is attached to the coil. Then if you take a permanent magnet and put a fact towards the coil like this, it will repel if you are facing the north of the magnet to the coil. If you have south facing coil, it will suck to the coil when the coil is powered.

I hope this helps. Can you draw a diagram of exactly what you build and the components you used, size of wire and how many wraps, etc... did you wrap it like I described or did you wrap it backwards? You can make the whole thing work in reverse but if you are able to easily, I would unwind the coil and rewrap it properly like the diagram.

I didn't post that Bedini link for you to go figure it out yourself, I just did that to provide a link. This thread is intended for first time schoolgirl motor builders.

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Thanks, but why is the coil getting so hot? This seems to be my biggest problem. Ill try it and get back to you thanks again for the help

Hi all, I'm new here so bear with me if this is all old hat.

I've been building my recreation of the schoolgirl and she's not behaving very well. I've already burned out two transistors, one by trying to solder the coil wire to the case--way too much heat!--and the other? Not sure what happened there. At any rate, trying to chase down magnet wire around here (Austin, TX area) has been difficult to say the least. Sure, you can get it at Radio Shack or Fry's, but only in ridiculously small quantities like 40 ft. (for #22) and 75 ft. (for #26). You can get a whopping 200 ft. of #30, but that's probably way too small.

So, the problem is most likely in my coil--I was only able to get 388 turns out of that 75 ft. of #26 which was wrapped bifilar with #24. In checking the coil with a voltmeter and spinning the rotor near it only around 5 mV max comes through as induced current. I'm guessing that this is not nearly enough current to bias the transistor on. When sending current through the coil, though, it generates a good kick. If I pulse current through it by hand, I can get the rotor to turn fairly well.

Anyway, a few questions come to mind about this circuit. First, I notice that there's a ground connection shown--is this strictly necessary? I saw on this page (near the bottom) that the circuit is almost identical (the only difference is the diode going to the recharge battery), but they caution that if there is no load that a neon bulb is required to keep the transistor from burning out. Is that the purpose of the ground in this circuit?

The other thing is I notice a lot of bifilar windings have the wires twisted around each other. Is that really necessary to get this to work? Perhaps the better question would be does it confer an advantage over winding the wires side by side (the way I did my coil)?

I'll post some pictures once I get this thing going. I'm almost 100% sure that the problem is that there's just not enough turns on my coil to induce enough current to bias the transistor. I've got some longer magnet wire lengths on order, so once those arrive we'll see what happens.

Hi Shamus,

If the transistor gets hot, I'm not sure it is from to few turns on the coil.

There are two things I would double check. Are the wires wrapped in the correct direction around the coil? Is the power wire going to + on the battery coming off around the right side of the coil towards you? And is the power wire going to the collector on the transistor coming off the coil from around the left side of the coil? And are the magnets for sure North facing out? These can still run even if everything is backwards and if so, it can heat up...I've experimented with that and got a hot transistor. I know this seems so simple that it can never be backwards but sometimes it is the simplest thing.

Have you tried spinning the wheel faster to get more induction to kick it off? Ideally, it will start by barely moving the rotor. If you have a lower resistance resistor at the base like a 10ohm, it will run way easier than a 680 for example but is less efficient but if you want to at least see if it all hooked up properly, drop the resistance and try it out. Lower resistance needs less speed on the rotor to get it going.

If the coil is wrapped correctly as indicated above and you hook it to a battery, the north field should push up on the North magnet facing out on the rotor. Of course you already know this but I'd make sure these 2 things are absolutely correct.

What components are you using? Transistor, resistor, diode? You can see in my picture here of the roller skate motor that I have a 2n3055 transistor and there isn't a 90v neon bulb. You don't really need it I don't think unless you have quite a few more turns.

You can twist the power and trigger wire together before wrapping on coil for a little more efficiency. Not necessary if you just want a simple model to learn from. I wouldn't worry about a diode going to a 2nd battery because you can always add that later. It sounds like you could use more turns. The wire I buy is sometimes on like 10 pound spools of various sizes (and weights)...much cheaper per foot than the radio shack wire. You don't need an external ground.

I hope some of these things help.

Hi Aaron!

As far as the coil goes, I followed the directions for winding as you set forth above. When I energize it with the (+) coming off the top lead and (-) off the bottom, it's a north pole with quite a bit of kick (I tested both the #24 portion and the #26 portion, and both are quite powerful as electromagnets ). I verified north on my magnets by hanging one on a piece of thread and seeing which side faced north, and labeled the side facing that way as "north". I then checked all the rest of my magnets by checking for repulsion with the known north face and labeled all the repulsed sides "north" as well. The core is made up of 2 1/2 inch nails epoxied together with the heads cut off, cut to length, and the points sanded down.

The components are the stock ones suggested by the schematic: A 2N3055 transistor, a 1N914 diode, and a 10 ohm, 1/2 watt resistor (too much wattage? seems unlikely to me). I'm using a battery consisting of 1.5V AA cells--one at 6V/2.3A, and another at 12V/8A. There isn't any deviation from what's suggested up above other than the lack of turns on my coil. Also, it doesn't induce enough current even if I give the rotor a good spin. Pictures follow. In the closeup of the circuit, the clips are not shorting out with the collector. I decided to go with clips after losing the second transistor and thinking that my diode had blown. This way, I can test components without having to solder/desolder anything.

Also, I connect (+) from my battery to the red lead coming from the top of the coil, and connect the (-) to the emitter (the clip on the bottom right of the circuit closeup). The second transistor blew when I gave the rotor a good spin and it acted as if it were magnetically braking the rotor--the coil and transistor heated up quite a bit on that run. I have since verified and reverified that the coil is hooked up correctly to the battery and that the coil produces a north magnetic field out the top that repulses each and every magnet on the rotor. The only thing that looks different in my setup is the number of turns on my coil, but there could be something else that I've overlooked.

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OK, yesterday I finally tracked down a local supplier of magnet wire after I found out that the wire I ordered over the internet wouldn't arrive for TWO WEEKS. At any rate, I finally wound 600 turns of #22 and #26 on my core (after removing the 388 turns that were already sitting on it ), hooked up the alligator clips, and success!

Some preliminary tests showed interesting results. It went at a pretty good clip when I had the 12V battery hooked up, but it seemed to run faster with only 6V (going by the pitch the bearings were putting out). Curiouser and curiouser. The current draw was only about 1/4 of an amp with the 6V, which should go down once I replace the 10 ohm resistor with a 680.

Also, my coil runs hot too. So much so, that loosened the epoxy on the back side of the coil spool! My guess as to why it's running hot is that there's just too much juice going through it, which upping the resistance should help with--I mean, come on, 10 ohms isn't much. At any rate, I hope to post some more rigorous results here once I get my coil back together.

And oh... The questions, the questions... More later.

Glad you got it working!

A few things for the efficiency is that you want as weak as magnets as possible but strong enough to just induce enough to trigger the base and also you want as much resistance at the base as possible while still letting the minimum through just to trigger the base.

The magnets you have look like the radio shack ones with the hole in the middle? Probably fine. Before you added more winds, it might have been possible to get it to run if you double stacked those magnets (with the fewer winds).

When you replace the resistor to 680, if it seems like it is difficult to get started, you can just double stack the magnets.

Anyway, post your results...looking forward to it. Also, you might see that when it gets going, it will speed up and start drawing up to the 1/4 amp you see, then it might start speeding up even more and the input might start dropping backwards. Kind of like shifting into higher gear but input drops.

I'll post a video of my roller skate wheel video...has about 600 turns. That is the very first one I ever did and it got me hooked! LOL

OK, now that I've swapped out the 10 ohm for a 680 ohm resistor the coil is running nice and cool. It might be better to advise using the 680 ohm first and fall back on the 10 ohm only as a last resort, since it seems to cause some serious coil heating. With the 680 ohm in place I do have to give it a pretty good spin to get it going, but that could be due to not enough turns on the coil, suboptimal bearings, unbalanced rotor, etc.

Now I'm getting some interesting results--before the 6V battery seemed to kick the 12V in the tail but now the 12V is doing amazing things! Here are some nominal measurements (these are crude BTW because my meter is kinda low end):

@ 6V: 70-80 mA, low RPM (guess-timate in the 100-300 range)
@12V: 150 mA, high RPM (guess-timate around double or so)

On one of those test runs with the 12V battery the rotor started spinning very fast (several times faster than the above measurement shows!) and I got a little nervous--I didn't want to have a magnet go flying into my chest at high velocity, tape or no tape. So I unhooked the battery and let it run down and decided to try again. This time it didn't spin up as fast and I couldn't get the coil as close to the rotor as before (definitely makes a difference in RPM!), so I shut it down again and found one side of one of the magnets had come loose. Apparently the glue I used doesn't bond well to ceramic magnets. So I got out the epoxy and glued it back down and tonight I gave a demonstration to my lovely wife (who doesn't know what to make of this stuff ) and it spun up to high RPM once more on the 12V battery. And, just my luck, another magnet came loose which put an end to tonights experimentation. I have a feeling I'm going to have reglue the entire rotor. Let this be a lesson to all of you experimenting with this thing: Make sure that you have some sturdy tape on the outside of your rotor--it will save you bacon!

At any rate, before the magnet came loose I was looking at the amp draw as the rotor spun up on the 12V battery. It started around 40 mA and then settled a bit around 100 mA. Then it took off; the draw was steadily climbing up to 190 mA as the RPM increased. Unfortunately, the noise from the bearings was making me nervous as it's a repurposed sliding glass door bearing meant for a vertical application and very low RPM--and here I have it horizontal and high RPM. I have a feeling it would have gone even faster and then the amps would probably settle back down. I'll have to get a box to put it into and just let it go as fast as it wants and see what happens.

After that, I'll just have to hang a diode between the coil and the collector and see what's there. I know there's definitely something there because one time as I was checking the transistor to see if it was heating up I accidentally shorted the collector and the base with my finger while it was running and received a pretty good bite--definitely more than 12 volts!

Ultimately I'd like to videotape the meter so I can make a nice graph of what's going on (basically amps vs. time, though I think amps vs. RPM would more interesting ). I guess before this is all over I'll have to find m'self a tachometer.

@Aaron: I forgot to mention, yes, the magnets are the Radio Shack variety. Good eye!

@Kevin: Thanks for the heads up! I definitely want to measure RPM in my setup to get a better picture of what's going on. BTW, would you be willing to share some of your insights with the rest of us vis-a-vis improvements you've found? Or has Aaron already laid them all out above?

OK, if this is getting boring just let me know and I'll shuddap. Some more interesting results tonight: It seems that the bearing has a large influence over the performance of this little machine. I built an eight magnet rotor (for the next step--results to be posted in a different thread once it's built ) and the short of it is that it performs better than the six magnet rotor.

Some of the gains are probably due to the fact that the eight was built better than the six; where the six has slightly offset discs in relation to the bearing the eight is almost dead on and where on the six the magnets are attached to the edge slightly non-uniform (one of the magnets is visibly skewed WRT the vertical) on the eight I made sure that they were uniform.

At any rate, when I first put the eight-magnet rotor on it didn't start at all with either 6V or 12V--I thought that maybe the magnet spacing was insufficient. But then I thought that maybe the bearing hadn't loosened up enough (it's the same bearing as on the six-magnet rotor ) and thus broke out the spray lube. Once I did that, it spun up quite well to some fairly high RPM. The current draw was around 120 mA @ 6V.

I then went back to the six-magnet rotor and to my surprise it spun up pretty fast (albeit somewhat slowly) and drew about 90 mA @ 6V. This seemed fishy to me, so once again I reached for the can of spray lube and gave it spritz while it was running. Once I did that, it started going faster while the amps dropped to around 50-60 mA. On subsequent runs, it never got above 50 mA while the RPM seemed to be fairly moderate (no tach yet--!).

So, to sum up, the bearings play a fair sized role in the performance of this machine. The ones I'm using have a fair amount of slop in them--somewhere in the neighborhood of 1-3 degrees from vertical which is bad, bad, bad. You can actually see the six-magnet rotor precess at high RPM. Also, I had to reapply the spray lube to the eight-magnet rotor at least once, as during one run it spun up to the 120 mA point and then a few seconds later lost all power and stopped completely. Good bearings are vital!

On a side note, I was wondering if anyone knows where to get various odds and ends such as spools and bearings. Internet searches tend to lead either to OEMs and industrial suppliers or to wild goose chases. I did manage to find a few sealed pump bearings at the local neighborhood giant home improvement warehouse store. I also found some perfect spools there--too bad they had $7 worth of #18 stranded wire on them. Where is Tinkerer's Depot to be found?

Thank you Aaron, and especially Kevin--the pieces are starting to fall into place! Of course it helps to have a copy of Free Energy Generation at hand. I didn't realize just how useful that photo gallery would be, especially when looking at John Bedini's site and wishing I had a closeup of some of his machines. This was a good first step, as all the things I've been reading about and seen are starting to come together as a coherent whole.

I have much more to say about the subject of the Bedini motor, but I think that this thread is probably not the right one to say it in. Having said that, I will say this: I started to make the next machine which will have four coils and four circuits (single-coil/multi-circuit will be the third iteration). But since it has only one coil and one circuit, you could consider it a SG motor. I was a bit disappointed to find that I could only get around 700 turns from my 1/2 lb spool of #22 wire--I was hoping to get at least 900. I guess it's back to the internet sites to get a 7 lb. (or thereabouts) spool.

At any rate, I got it running last night and let it run overnight just to see if it would, and it did. Even with the lousy bearing I have in the rotor. I put the diode in between the coil and the collector to see what was there and lo and behold I saw some voltage spikes peaking around 200V! Obviously my instrument is too slow to really see what's going on with that part of the circuit but it's enough to get an indication. Needless to say, it's a bit stunning to see it for the first time.

And since at this point we're no longer talking about the basic schoolgirl design, I will continue this discussion in a more appropriate thread. Complete with pictures, too!

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@Kevin: If you didn't see my encouragement in the other thread, let me reiterate here--by all means do it an hour at a time if you have to and please post updates!

Ok, here's what I see happening in this little circuit.


What follows is my take on what happens during one cycle. When Mr. Bedini said that his monopole motor was an attraction motor, something just didn't sit right with me. But, of course, now I realize he was right:


With no current flow in the circuit, a rotor magnet is a attracted to the coil core and moves toward it. This induces a tiny current in both coil wires. Electrons flow from the back of the trigger coil to the front, through the resistor and diode and back the the rear of the trigger coil. If enough current is present, it also flows through the base of the transistor and into the power coil.


Once the base of the transistor has current flowing through it, current from the battery flows from the negative terminal of the battery, through the emitter of the transistor and out the collector, then through the rear of the coil and out the front to the positive terminal of the battery. At this point, the current flowing through the coil creates a strong magnetic field, temporarily magnetizing the coil core with a north pole in front and a south pole in back. This gives the rotor magnet a good strong kick in the direction it was traveling.


With the rotor magnet kicked away, there is no more induced current in the coil. Current flow at the base of the transistor stops and so the current path from the battery, through the transistor, is interrupted. At this point the magnetic field in the coil collapses and, coupled with the brief amount of time that the coil was energized by the battery, a radiant event occurs in the coil accompanied by a high amount of voltage appearing with no current. As the next magnet on the rotor comes in, it is attracted to the coil core and the cycle repeats itself.

Now this is what I'm seeing, but I could be flat out wrong. I'm just groping for an explanation of how this little thing works. One counterexample is in the Bedini/Beaden PPA where there is a picture of a waveform showing current in the trigger side of the circuit, one which strongly suggests a type of "ringing" oscillation as the current ramps up. Which means that my explanation, while plausible, fails to explain the ringing oscillation of that picture. Obviously, there are still some gaps in my knowledge here.

Hi Shamus,

This isn't a direct response to you post...it is something I posted 2.5 years ago in icubenetwork when it was online in relation to John's circuits and the water fuel cells. But, it applies to these circuits and is a perspective hardly anyone is talking about yet.

---------------------------------------------------

qiman13
Posted: Wed Mar 16, 2005 4:09 pm Post subject: coil importance

The coil is extremely important. There is not one single component
or aspect of this schematic that is not that important. Every
piece is crucial to consider. That becomes apparent when you
start to fine tune the energizer. A few ohms difference in the
resistor at the base can make a big difference in efficiency.

Impedance matching is important. You have to think of the circuit
as a gas pressure control system, since the aether acts exactly
like a gas under pressure.

For example, on one motor I just put together, with a 12volt
1.5 amp hour gel cell battery on one side and a 6volt on the output
smaller amp hour..the motor gets up to about 2600 rpm and
outputs so much radiant. That is because with the higher
impedance on the back end, it is acting like a pressure relief valve
with a tight spring. The motor can only open up so much.

When I put the same kind of battery on the back end 12volt, etc...
The energizer speeds up to 4800 rpm and output a hell of a lot
more radiant into the battery. That is because it is like having a
pressure relief valve with a looser spring or you can picture it
having the ports on a head bored up or having racing headers
instead of a stock exhaust manifold. It lets more out with less
back pressure.

That is what is happening. It isn't an electrical schematic, it is a
device that moves the Heaviside flow around under different
pressures. It is a valve for gas.

Shamus,

I think you're very intuitive with this.

I was thinking the same thing with the collapsed field attracting the north. Have you seen John's pics of the fields around the rotor.

Think maybe on this one that squeezing out in between each magnet is a "scalar south" field. All the souths facing inwards are repelling and have nowhere to go but out between the magnets. Not only that.... if you take two identical magnets and put north up and space them a bit apart, there is a south field coming out between the two.

There gets a point where the speed is such that as the north field is out and possibly hasn't collapsed yet, the south field is attracted to that

I suppose there are different ways to look at that but get a compass or other magnets and experiment with feeling the south coming between the magnets

A small shipment of magnet wire came in the other day and so I finally got to wind up a 1,000 turn coil. I've been reduced to fabricating my own spools from PVC pipe and other odd pieces of scrap and scratching my head trying to figure out how to keep flanges of the spools from falling off once too many turns are on it. I'm still waiting for the 11 lb. spool...

Since I didn't have any batteries hanging off of the diode, I figured this thread would be appropriate to post some more preliminary results. I apologize for the paucity of hard data, but I just don't have enough meters to do the job. At any rate, starting the rotor with the 1,000 turn coil is much easier. Running 12V, the current draw consistently went to 230 mA while when running 6V, the current draw was consistently 90 mA (margin of error is +/- 10 mA). I did test the 6-magnet rotor with the new coil at 12V and it drew a steady 210 mA (didn't check 6V).

(slightly-offtopic)I did check to see if the rotor RPM would drop with a load and it did as I've seen it do before.(/slightly-offtopic) It's interesting that the 12V battery draws more than twice the current of the 6V battery with the same setup. I guess that means that the resistance I have set up on the trigger side (680 ohms, 'natch) is more closely matched (or 'tuned') to the 6V battery than to the 12V. The resistor isn't soldered in yet, so this calls for some experimentation. One thing I notice about John Bedini's circuits is that there are no pots in any of them. Apparently he knows his coils/circuits well enough to choose an appropriate resistance and leave it at that.

One other item of note is that the current consumption seems to only go up no matter what voltage I put on it. Which of course makes me wonder if my setup is correct, since it's supposed to speed up and then have the current draw go down. But then again, perhaps that effect can't and/or doesn't occur in a single coil setup--I'm eager to get the multi-coil going. It also could be that I have lousy bearings and that the motor is trying to overcome that but just can't.

In answer to your question, Aaron, yes, I have seen John's picture of the magnetic fields around the rotor. It's funny, I always assumed those spokes were north fields. It sheds a whole new light on things to see that those are south fields! Yes, I tried magnets in those spaces and I have to tell you, it was a little freaky to see the north face of a free magnet stick in between two rotor magnets which, as you know, are north facing out! John was right when he said this machine was deceptively simple.

Ok, first the results, then the analysis:

It was pretty surprising to find self-resonant behavior--I can see how people could get distracted by it. It's also easy to see why the coil resists the rotor in that mode, since the circuit no longer self-regulates at that point. The rotor would have to be turning at the resonant frequency to stay spinning!

My meter can only measure down two significant digits at these amperages, so I'm pretty sure there's some differentiation at those levels marked 150 mA. In particular, I'm thinking that 1374.3 ohm is probably closer to 150 mA than the other values.

I'm also finally seeing the 'shifting into high gear' phenomenon that you were talking about, Aaron, with the power consumption going down as the RPM goes up. It seems tuning is the key here.

Hello everyone,

Thought to make a first post here since I will have some questions about my contraption that I've built...I mean Bedini Motor. I can say that it actually works but I have some questions/concerns that I'd like feedback on.

I will soon post photos of my motor as well as my Fluke scope waveform because one of the questions relates to the signal, right now I just thought to make a first post...

Bedini SG (roller skate wheel motor) video posted on youtube.

YouTube - Bedini SG - Schoolgirl - Bare basic model

A few days ago I got some sealed lead-acid 12V batteries rated at 7Ah and so today I decided to give it a shot. I checked the resting voltage of the battery I was going to use and it was sitting at 12.80V. I tried to measure the amps coming out of it but I nearly burned up my wires in trying to do so. I think the meter was reading around 15A or so before I realized what was happening to my wires.

So anyway, I hooked it up to my setup (with 1374 ohms) and got lots of noise out of my coil and strong repulsion on the rotor. The amp reading was negative. Something strange was going on here...

So I pulled off the resistors and stuck what I thought was 680 ohm resistor in and this time it spun right up. The current draw was around 540 mA (!) while the RPM was low. Well, it turns out that I mistook a black band for brown and so it was really 68 ohms on the trigger. A bit on the low side.

I then put an honest-to-God 680 ohm resistor in place and it showed resonance right away. No chance of starting the rotor there. I substituted a 390 ohm and this time no resonance in the coil although the current draw was around 390 mA with an RPM somewhere in the middle range of what I've seen with this setup.

With around 490 ohms the RPM did go up while the draw went to around 360 mA. I had to stop testing, though, because I noticed that the resistors were getting extremely hot! Now these are only rated at 1/4W, but still, there shouldn't be that much juice flowing on the trigger side, should there? I mean, we're talking mV/mA range here on the trigger side. At any rate, I'm off to get some beefier resistors so I don't have to worry about them burning up.

On a side note, I figured it might be useful to power this thing from a stock wall-wart PSU. I found one rated for 9VDC at 1A, but it turns out these labels lie. I measured 12.83V coming out (hey, it looks just like a fresh battery! ) at around 5A or so. So after my experiments with the lead-acid battery came to a screeching halt, I decided to try to power the current setup (at 490 ohms) with the PSU. It spun up to high RPM with only around a 270 mA draw.

Now I'm really confused here. I guess I shouldn't be too surprised that the battery, with it's higher amps, should be pushing more current through this circuit than the PSU which is putting out about three times less amps. But it seems like the current draw should be the same, no?

On another side note, there's a good lesson here about resistor selection. It seems that the optimal resistance depends heavily on the voltage being supplied on the front end. I checked the voltage on the 12V battery (made up of 1.5V cells) and it was around 10.5V. Boy, do I feel foolish. (/me smacks forehead)