New Two Coil Monopole

[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

[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]

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.

[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]

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.