New Two Coil Monopole

[BobZilla]

Greetings friends,

I built a new monopole and I wanted to share the build with the group.

Let’s start with some parts listings. I used some non standard diodes on this build. They are ultra fast switching and the main reason I tried them is because they have a lower voltage drop. For beginners reading this, you are better off using standard parts so that you can get help from other members with tuning and troubleshooting. I have gone out on my own with this and cannot say yet if there is any advantage, it is experimental.

The Collector diodes:
Rectron 3A 200v 35ns Part# SF34-B

DATA SHEET:
http://www.mouser.com/ds/2/345/sf31-sf37-36181.pdf

The B & E diodes:
Rectorn 1A 100v 35ns Part#SF12-B

DATA SHEET:
http://www.mouser.com/ds/2/345/sf11-sf17-22674.pdf


On the base resistors I used ¼ watt 274ohm 1 percent tolerance and a 500ohm pot for adjustments.

The transistors are the standard MJL21194 all matched (8).

The system has two coils mounted; each has four 18awg power and one 20awg trigger. The second trigger wire is not currently connected to anything. All of the wires terminate on a standard terminal block with ring connectors.

The wheel is a heavy duty 26 inch wagon wheel (not a bike wheel) with ½ inch bearings. I glued the bearings shut and installed a ½ inch steel axle to utilize the mechanical energy. The axle is mounted on some roller bearings out at the ends. These are the type of bearings used on assembly line rollers and have a 20 percent self adjusting swivel to prevent any binding on the axle.

I do not have anything attached to the axle yet but I am thinking of putting a small wheel with magnets to hook up a generator coil assembly, also maybe a fan like Mr. Bedini or a pulley system for doing some kind of mechanical work. I am getting a lot of torque from this setup because of the wheel size and it is also pretty darn heavy which makes for good inertia once it gets up to speed.

The magnets are the standard ceramic type and there are 16 of them mounted on the wheel. I used JB weld epoxy to glue them on and did a second coat on top of the first.

I have laid out the circuit in a way to allow a few options for running. The transistors are configured in branch mode with two banks of four. The switches at the top of the board allow for sending all outputs to one side, the other side, or branch (both sides).

The switch on the lower left is for switching to generator mode and the lower right switch is the primary on/off switch. All of the bus bars are made with 14awg solid wire; the kind used for house electrical. The clip leads are made with 10awg braided and all connectors are soldered.

Having just completed the build last night I do not have a lot of experience with the system yet but initial testing looks very good. I have been charging up two 75AH batteries in branch mode with no problem. It seems to like to run with a 1A input when in mode 1 operation. That equates to just a little bit of resistance on the pot over top of the base but not much. I may put a fixed resistor in the trigger path on a switch to change over from the pot once I figure out exactly what it like to run on.

Here are a few pictures of the system.

[John_Koorn]

Nice job Bob!

You may find the collector diodes are under-rated at 200V. I'm using ETX0806 in some of my experiments and they seems to be performing quite well. They are 8A 600V 14nS.

DATASHEET:
http://www.vishay.com/docs/93546/etx0806m3.pdf

John K.
John K.

[BobZilla]

Thanks John. Man it is just so much fun when you finish a new build isn't it. I am loving this machine but I already know I may have to adjust a few things.

So far those diodes are holding up but I know what your saying, at least 300v would be nice. As it is right now a few of them get about 6 degrees above the others and the set of them stand about 15 degrees over ambient temp.

Another observation is that although I thought that 1/2 inch steel rod would be a great axle it is bouncing slightly, bending you could say. Not much but it does flex. If I had the legs closer together it may not do that but I am thinking abot putting a wider axle on it. The axle and hub can go thicker if I get bigger bearings so I have some room to improve that.

Over all though I am happy with this thing so far. I have only had it running since last night.

Another thing I need to look into is when checking the pulse with a led I can only get it down too two. I am not sure if the two coils has anything to do with that or not since it is my first multi coil. Tomorrow I am going to try re-adjusting the coil gaps and see if I can improve it.

[Tom C]

Bob,

if you switch from solid rod to a 1/2 inch thick wall pipe the bounce should leave, as long as it is not the bearings off center in the races., please measure freewheel time, you may only be getting to 2 pulses because of rotor speed, and thats all about friction

Tom C

[BobZilla]

Tom I think you are right about the friction and speed.

I was able to get down to one pulse but at the cost of lowering the resistance on the pot quite a bit and my primary was drawing 2 1/4 amp. I do not want to run the machine on that much juice even though temps were all still good on components I just don't like drawing that much. Down at 1A draw I can only get the 2 pulses no matter what I have tried like re adjusting coil gap.

I KNOW I have some unwanted friction because of how I am keeping the Axle from drifting. I had forgot to get a good collar with a set screw to put on the axle so I rigged a piece of PVC on the back end of the axle while I am waiting for some collars to arrive. The axle wants to drift forward so I had slipped this little pvc over it and put a zip tie behind that so what happens is when the axle wants to pull the pvc spacer butts up to the rear bearing and then the zip tie binds with it, keeping the axle from drifting.

It is not ideal at all but I had rig it up that way until I could get a better solution. It is certainly causing a bit of drag and that may be the problem.

I will try to get a pipe as you suggest for the axle, makes a lot of sense to me now that you mention it. You get that strength from the internal arc of the pipe pushing on itself.

I am going to keep fine tuning this thing and see if I can get it running exactly how I need it too. Over all it runs pretty good but I need to correct the little details that I couldn't notice until it was running.

Tell me though how bad is it to have the two pulses instead of one as it runs currently? All of the transistors and diodes are keeping nice and cool and the draw rate is nice with good charging. If I didn't know about the 2 pulses instead of one I would think it was great but I do know that it is double pulsing.

Thanks for the help

[BobZilla]

Ok so I went to the hardware store to get a pipe and the only thing I could find that would fit was "steel tube". I wanted to find heavy duty pipe but they didn't have it with a 1/2 inch outer diameter. I got the tube and got home with it. When I slid it into the bearings I noticed that it was not a good round tube and would not make for a good axle, I like the idea but the material I found was not going to be suitable.

So I worked on the axle I already was using. I took and drilled a hole in it and slid a cotter pin through along with a few washers. That replaces the PVC/zip tie spacer thing I had on it before. This seems to give much less friction and I also carefully leveled out the axle as best I could.



I took out the inner bearings that are glued shut and cleaned them off & re-glued them then presses them back into the hub. Over all it is much smoother now than it was. I may have had one of those pressed in a little crooked or something before, not sure. I used a big socket this time that fit over the whole thing and smacked it in with a hammer and they seem to have set evenly into the hub.

So I let all the fresh glue dry over night and started playing with it this morning. I am still getting the same result as far as timing goes but it is running smoother mechanically. I made a short video showing what I am up against here. It starts out showing one pulse but the draw is way up at 2 1/4 or so. Then I back it down to where I have been runnig on the two pulse at around 1A draw and also a little lower just to show the multiple spikes.

https://files.secureserver.net/0sm4O8XAAipOba


I was looking at it and thinking maybe I do not have the magnets spaced close enough? I didn't want to over lap the poles so they are fairly far apart. What do you guys think? In the picture below you can see how they are spaced and I also put one next to the timing magnet to show the spacing if I were to double up on them. I could slip a magnet in between all of them and have it come out even if I wanted too but I'm just not sure if it would help.

[Yoe777]

What shaft / bearings did you use? Did the new rod just fit in after the old one?

Thanks for the pics!

[Yoe777]

Looks like you were constructing part of my answer soon as I was writing it.

[BobZilla]

Yoe,

The thing to keep in mind about this is that it is not a bike wheel. This thing is supper heavy duty and super heavy in general. It is one of those wheels you would put on a utility cart. That is why I am using the 1/2 inch axle, to support all the weight. It originally came with 3/4 in bearings which at the time I thought would be too big so I down sized the inner bearings to 1/2 inch and got a steel rod for an axle. The good thing is I can always go bigger because the hub will accept larger bearings.

Here is the wheel:
http://www.northerntool.com/shop/too...1764_200331764

The outer bearings that it spins on are roller bearings, not ball bearings.



As you can see from the specs these things are self alighning, can carry 1040 pounds, and are rated up to 22k RPM

[Tom C]

Bob,

what is the freewheel time with your modifications? run it on one coil..... if it runs faster on one coil than on two then either your magnets aren't exact or the coil spacing is not perfect multi coil machines are hard to tune

Tom C

[BobZilla]

Tom I will have to check on that free spin for you but I don't think it will be comparable to most other systems because of the wheel itself is so darn heavy. I knew this would present special issues but the thougt behind it was that one I get up to speed the extra weight would help out with running mechanical loads from the inertia. I am also thinking that I need to just run it awhile to make sure the bearings and the axle get smoothed out. I don't really know if there is any break in period for them but perhaps they will smooth up after awhile. I could also try different lube. Right now I just have some 3 in 1 oil on them. I thought about maybe some white lithium grease instead.


Any opinion about the magnets, I mean adding the others? As it is I spaced them out every other spoke so I could double up, just need to be careful not to crowd those poles. I would hate to go to all the trouble of installing them and find out I have killed the darn thing.

I have checked very closely on the spacing and how the two cores line up to the magnets. Everything is in very tight tolerance as I have it adjusted. The spacing was easy to get even because I used the spokes as a guide and the coil mounts have wiggle room. I drilled out larger holes where the bolt goes through so I can slide the coil a little in any direction to adjust. As best I can see they are alighned very well.

I did try running it on just one coil before I fixed the axle and it ran about the same. I will have to try it again to see how it is doing now. It was producing the same spikes on one coil as two. I was really testing to see if the two spikes had anything to do with having two coils. I knew logically it didn't but I just wanted to make sure and it was not that.

Ultimately I am leaning towards doubling up on those magnets but I'm not quite there yet. I am thinking that because it at least seems that with the wide spacing the core just cannot attract the next one in with enough force to get the speed up where it needs to be, accept when I push way to much juice on the trigger. More magnets should help pull in faster with less force needed but i just don't know. It's a lot of work just to find out if I am right ;-)

[John_Koorn]

Bob, more mass means you should get a longer free spin time as there is more kinetic energy stored in the wheel.

John K.

[Tom C]

magnets are related to current draw so more magnets more events per rpm higher draw.... its fairly linear. with regular north magnets a single stack is fine unless you are having trouble getting the transistors to fire for whatever reason. the mass will do you no good if friction is to high on the bearings. I suggest triflow with the race covers removed.

I wish I had a better physics background but friction is one of the most critical factors in storing energy in the perimeter of a spinning object. the less friction the more inertia is conserved to maintain rotation.

Tom C

[BobZilla]

I really appreciate all of the advice guys.

I have been playing around with the new machine and notice something that seems to go against what is commonly believed when it comes to those pulses per magnet. Now I should say that these are just on the fly observations and may not pan out if I take the time to do some more thorough testing which I do plan to do. It's just right now I am fiddling with the thing.

So what I have noticed is that I actually get a better charge rate from three pulses than two or even one. On my draw it works out to be for three pulses I draw 700ma, 2 pulses 1A, one pulse about 2 1/4 A.

Now what I mean about the charge rate is that watching on a charge curve it climbs much more rapidly at the lower RPM and draw which produces three pulses (using led timing indicator). The ceiling is lower of course but the rate at which it climbs seems faster. Just to get some quick results to see if this pans out I am going to charge my garden battery up fully and drain it for a given amount of time with a 7 watt bulb. Then I will charge it back up with each of these three settings draining it off the same each time so I can compare.

I am at a disadvantage because I do not have an O-scope to really see what is going on like the shape of the spike or if in fact my led thing is telling me the truth about the number of spikes. I have set up a new led timer how Mr. Bedini showed in one of the vacuum video's with a red and a blue out of phase with each other so I can see the charge and the discharge. I was looking at that wheel of his, the original and you know the spacing looks about the same as what I have on this one and I think the number of magnets is the same (16) but I could be wrong about that.

Don't get me wrong guys this machine is charging batteries fantastic, I am just fixated on this single pulse which I cannot obtain without drawing harder than I want too with it.

Can anyone really elaborate on why we need one spike? If I remember correctly the single spike shows up on a scope with much greater voltage and a cleaner sharper point than if you have multiple spikes, is that right? What is the cause and effect of running with two or three verses the prescribed one spike? As I say I know what it is supposed to be doing but with this particular machine I am seeing better charging rate with three and it cost much less on the draw.

I will post back with those charge curves after I get a chance to run through them.

[Gary Hammond]

Hi Bob,

The outer bearings that it spins on are roller bearings, not ball bearings.

[ATTACH=CONFIG]2818[/ATTACH]

As you can see from the specs these things are self alighning, can carry 1040 pounds, and are rated up to 22k RPM

These bearings are great for an application that utilizes a hardened, precision ground shaft with light oil lubrication. They will be very rough running with a cold rolled and/or cadmium plated shaft from a hardware store. Un-caged needle bearings will carry very heavy loads but produce more friction than ball bearings because of their greater surface contact area even when used with the proper hardened shaft.

Replace them with ball bearings. Then remove the seals, clean out the old lube, and lightly re-lube with tri-flow or equivalent. This will produce a much smoother and freer running wheel with much greater free spin time!