Electronic Geek's I have an invetion

[thudpucker]

I'm hoping to rob some voltage off the outside of the flywheel magnet of a Briggs & Stratton 5 Hp engine.

My plan is to stick a chunk of Ferrite up next to the outside of the Flywheel.
I'd wrap some wire around the Ferrite.

I'm hoping the discharge of the homemade transformer will charge a large Capacitor.

With the output of the Cap, I'll operate two solenoids.
One will pull up and hold.
The other will be a pulsing Fuel inlet valve.

I'd like to know about the size and number of coils I'd need to charge a large Cap. Some old Radio Cap or similar.

Would I start with small diameter wire and lots of turns. Or larger wire and fewer turns?

Will the large cap discharge all at once through my two soleonids? Or can I get enough Current to make the solenoids work after the engine starts?

[CDK]

Some reasons why it doesn't work:

1. There is almost no magnetic field on the outside of the flywheel because the iron rim shorts it out (absorbs it).

2. Ferrite is intended for much higher frequencies. The B&S engine runs at 3600 rpm, that is 60 cps. For such low frequencies you get much more energy yield from an iron core (use an old transformer).

3. The capacitor doesn't bring any extra electrical energy, it just delays the peak voltage, so causes a shift in cos phi. As soon as the magnetic field changes polarization the stored energy in the cap flows back to the coil.

4. Operating a solenoid as an inlet valve requires a lot of power because it has to push or pull against a spring to obtain a short response time.

The proper way to carry out this experiment is to put a coil inside the flywheel, rectify the output voltage and use electronics to control the solenoid timing.

[thudpucker]

Yezzir.
I was afraid of that. I was hoping to do this without sophisticated electronics.
I kinda knew I'd never make it work as planned but I was hoping.

My idea is to solve the spring and fall Carb problems by using a fuel open/shut valve (the first solenoid).
Then interrupting the fuel flow with the second valve.That one will open and shut each intake cycle.

So it wont actually be a fuel injector. It will open about the time the intake 'Low Pressure' exists, and shut quickly at Idle. It does have a light spring to help shut it and hold it from bouncing.
At speed the valve would open at the same time but shut later on.
The timing would be a mechanical moving plate.

OK, thanks for that information. Now back to the Idea napkin!

[Luckless]

I strongly suggest actual paper and a drafting board. Plans without coffee stains are always easier to work from. (Why do you think drafting boards are often nearly vertical? So that co-workers can't come in and set coffee mugs on them.)

However don't be scared of electronics. Very basic timers and such aren't all that painful if you take a bit of time to learn them.

[thudpucker]

I used to love the learning part of working. Now it seems like I need help all too often.

I dont often go for coffee in places where the tables are tipped at such an angle.

At times I've seen tables tipped like that where they serve booze!

[pistnbroke]

CDK is wrong about the Briggs ...the magnets are on the outside of the flywheel ( as is the magneto/ignition coil ) but even if you mount a steel carrier and coil close to the flywheel you will find that because there is only one spinning magnet in a briggs that you only get one pulse of electricity per rev..not efficient ....other flywheels have multiple internal magnets and multiple coils to get a more continuous supply ....

[CDK]

CDK is only wrong some of the time.

B&S makes a lot of different engine models. I guess this 5 HP has a light alloy flywheel with a small square where the magnets are.
Because Thudpucker wrote he wanted to mount a coil outside, I assumed the ignition coil would be inside.
For most models B&S offers a part they call alternator: an iron core coil with a rectifier.

[pistnbroke]

b & S in small sizes is usually on the outside ....just keep us informed on your inovative drive on your boat ....

[thudpucker]

B&S has a single magnet in an alloy fly wheel with points and a Magneto inside the flywheel. There aint much room in there for another magneto of any size.

I have a piece of ferrite in an "E" shape. I thought if I wound wire around all three legs of the "E" , with a Diode on all three legs, I could come up with a "3" pulse Generator.

I thought the Ferrite would be good at Hi Rpm as it would offer less Reactance.

I'd wind up with 3 little 'bumps' going through 3 diodes to a big Cap. I was hoping my big Cap would hold so much of a charge that it would bleed off slowly through those two little solenoids.

The 'fuel' valve solenoid could be a latching relay that would stay up until the power to the relay was cut. That's the on/off switch.

When the Fuel inlet valve shut the fuel off, the Pulsing Solenoid would continue to operate until the engine ran out of fuel, because the big Cap would be bleeding off through it.
Leaving no residual fuel to stick or gum up anything.

With my circuit a big Cap would be better than a Battery, because a Battery would need some more regulation circuitry.
I hope this is big enough to read.

[CDK]

Yes it is big enough.
The diodes are essential, but instead of ferrite, use an iron core. It is much more efficient at low frequencies. The core should be reshaped to fit exactly around the flywheel, the air gaps as narrow as possible. You can draw approx. 10 watts that way.

[thudpucker]

at the risk of wearing out my welcome, a question on the wire on the core.

Lots of turns of smaller wire?
Or as much as I can get on the Iron Core of Larger wire?

I'll get the Largest Diodes I can find. Big PIV. It dont matter how efficient they should be, I don't want a failure.

I have some old TV's etc where I can scavenge some wire.
I think I have that big Cap around here somewhere.

I think I'll make three separate Iron core's. Instead of an "E" shaped Iron core.
They will be some pieces of 1/2" or 3/4" Re-Bar about an inch long.
I'll measure the height of that Flywheel magnet and match the Core to that.
I'll ground the Core to the block. That will make the application simpler.

I don't have a Scope. Just a pretty good ol' Fluke.
I turn the Briggs Flywheel with an Electric motor/socket on the flywheel nut.
That way I can see the voltage coming off the Core windings while my wife holds the Drill.

[Fanie]

You can stick a few flat magnets on the outside of the flywheel.

The arangement should be N S N S N S and so on.

The more magnets the higher the frequency would be. 400Hz is about optimal for iron and is much more efficient than 50Hz for instance.

The higher the rotation speed and the more wires the higher the output voltage would be.

The energy goes 4 x more if the rpm doubles or if you double the magnet count.

You can use neodamiums, freely available nowadays. They don't like salt water so you HAVE to conformal coat them or they will disintigrate in no time.

These neodamiums have huge magnetic fields, and can transfer quite a bit of energy. The denser the field the better energy transfer will take place.

Remember they will require mechanical power to make juice. Don't underestimate this. It is not free energy you gain somehow.

Each magnet gets a coil, their polarity gets flipped also. Induction should be from far negative to far positive because of the magnet N S N S arrangement.

The coils are connected in series.

An iron core in the coils improve energy transfer.

I suggest you stick one magnet on the flywheel, wind one coil of about 0.6mm wire and play with it a bit. Start with a 100 winds should give you an idea.

The distance the coil is from the magnet is critical. The smaller the better.

Remember to load the coil so you can get an idea of the force required to turn this thing.

Mind your fingers, from experience.

Make sure your compass is still usable when you throw these magnets in there.

Good luck

[CDK]

Originally Posted by thudpucker

at the risk of wearing out my welcome, a question on the wire on the core.

Lots of turns of smaller wire?
Or as much as I can get on the Iron Core of Larger wire?

I'll get the Largest Diodes I can find. Big PIV. It dont matter how efficient they should be, I don't want a failure.

I have some old TV's etc where I can scavenge some wire.
I think I have that big Cap around here somewhere.

I think I'll make three separate Iron core's. Instead of an "E" shaped Iron core.
They will be some pieces of 1/2" or 3/4" Re-Bar about an inch long.
I'll measure the height of that Flywheel magnet and match the Core to that.
I'll ground the Core to the block. That will make the application simpler.

I don't have a Scope. Just a pretty good ol' Fluke.
I turn the Briggs Flywheel with an Electric motor/socket on the flywheel nut.
That way I can see the voltage coming off the Core windings while my wife holds the Drill.

The simplest way is to use a cheap transformer. A good one has E and I laminations interchanged and will fall apart when you cut off one side. The cheap ones have all the E's in the same direction and the packet of I's is welded to it. These are easy to removed.

Use one with approx. the power you may expect, say 12V/1A. The wire should be something like 0.8 mm in Metric, that would be #20 if I remember correctly. All 3 legs get the same number of turns, the more the better.

Fanies idea to add magnets is not bad, but make sure they are bonded well to the flywheel. These "rare earth" magnets like neodynium or samarium/cobalt are brittle and very dangerous if they hit each other (and you of course).

Use diodes like 1N4000x or 1N540x, they are small but powerful enough.

[Fanie]

brittle and very dangerous if they hit each other

Yes I forgot to mention. Under impact if they break the particles fire up like starlighters. Be carefull, a fire risk. Handled properly however, they are the best there is for generating power.

How about a belt and a smallish BLDC motor to generate instead. You get DC out too...

[pistnbroke]

put say 20 turns of of any old wire and measure the voltage when running ...then multiply up the number to get the volts you want ,

I did similar but used an old b and s magneto core ..personnally it was a waste of time due to the single magnet system ON THE OUTSIDE OF THE FLYWHEEL IN BRIGGS ENGINES ....not enough output current .
On some briggs you will find a mounting for a second magneto core is already in place under the tin shroud