How To Increase Magnetron (Magnet) Ignition High Voltage For Mower Engine?

Thread Starter

russwr

Joined Aug 29, 2017
62
I need a circuit for using only a standard lawn mower Briggs magnetron to increase high voltage output to 24,000volts! The flywheel magnet instills 5-8v PULSE ONLY, trigger shorts the primary to ground, then back EMF creates negative -130 volts to run the secondary side for negative 12,000volts. The primary is very low .2 ohm resistance. The metal core end connects to ground for secondary side and trigger side, + the trigger connects primary to ground. The open tab terminal is accessible for primary wiring . This can be attached to 12 volts DC to superimpose on the 5-8volts, to get a higher secondary output, with a primary current limiting RESISTOR for max 4 amps, and keeping the coil from shorting out. Mower ignition is called autotransformer with 3 terminals only. The aftermarket solid state trigger module called Stens operates when the voltage is indicated going into primary from the North pole magnet. The internal transistor switches on temporarily to ground. This connection maybe could be used for another transistor to instill 12v DC superimposed onto the magnet voltage. This would then instill a higher back EMF that runs secondary side for higher, high voltage. Also, a different burst oscillator mode, for single pulse desired, could be used and then shut down by the trigger. Maybe the 12v DC has to be triggered in, so that it doesn't short the primary winding to burn out. That's the problem. Ideas??? I have magnetic hall switches to operate a transistor to switch in the 12 volts. ( A voltage doubler circuit requires only AC input) The small unit being sold for autos is a high frequency oscillator that raises also up to 16 volts pulse to the ignition, - was called firestorm for as $8 to $75. A man in England on YouTube was adding parallel capacitor to TV fly back primary to raise up high voltage as the resonant frequency of wire and ferrite core is way higher, and run from high frequency oscillator.
I already tried increasing magnetic field by adding neodymium multiple magnets on top of North pole magnet with no volts increase. ((After 1982, The Briggs ignition coil has built in solid state transistor and trigger coil under the epoxy, and then all are called MAGNETRONS. - Uses same name as the glass tube oscillator in a microwave oven.)) The recent Magnetrons now look different and have what's called the universal type trigger, which is better. The other model ignition Magnetron, with 2 ignition cables, has secondary side not connected to primary side. That dual cylinders Briggs engine fired one side negative high volts while the other spark plug fired positive high volts. The system is still single pulsed based,- NOT AC.
The way earlier pre-1982 Briggs ignitions were called MAGNETO with points + condenser, that used plain autotransformer without any solid state. I had earlier contemplated to add a south pole magnet next to North pole one, to get AC to run the Primary of a MAGNETO transformer, and use double universal triggers with blocking diodes to get it to run. Only then, can the common AC voltage multiplier be used to increase the high voltage on the secondary side. That is also still a primary+ secondary auto transformer system. If that was used , the secondary side has reduced high voltage, as the metal core has to be mounted upside down to get positive high volts. - The primary is not then part of the secondary when fired. Any ideas?
 

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LowQCab

Joined Nov 6, 2012
4,192
You haven't stated a basic problem yet.

On the Engine that the Ignition-System was designed for,
increasing the POTENTIAL-Coil-Output-Voltage will do nothing to the performance of the Engine.

The Compression-Ratio,
in conjunction with the Spark-Plug-Gap,
will determine what the highest actual Secondary-Voltage will be.
If the Factory Compression-Ratio,
and factory recommended Spark-Plug-Gap are used,
the Secondary-Voltage will remain unchanged
regardless of any other changes You may make to the Ignition-System.

Operating the stock Ignition-System with the Secondary disconnected,
or operating the Engine with an excessively large Spark-Plug-Gap,
may damage the Coil by way of causing an excessive Secondary-Voltage to be developed
that the Coil is not designed to withstand for long periods.
This may cause an unexpected failure of the stock-Coil,
and/or, cause High-RPM / High-Load-Misfiring, which may be very difficult to detect,
or may be mis-diagnosed as "Valve-Float".

If You would like to experiment with High-Output-Ignition systems for a small Engine
I would suggest looking at the Aftermarket-Ignition-Parts used in Racing-Karts that
run Straight-Methanol, in conjunction with an extremely High-Compression-Ratio.

What is the exact Brand and Model of the Engine You are modifying ?

What type of modifications have You made to your Engine ?

What is the problem that You think You are experiencing ?
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Ya’akov

Joined Jan 27, 2019
9,230
Magnetron ignition? Wonder how the kilowatt scale microwaves may be used for such purpose if any.
If you use the magnetron to make a spark, it doesn’t have to be too powerful! On the other hand if you are trying to ignite the fuel using the electromagnetic radiation, I am not sure there is a power level that would work. Of course, if you get your fuel from a shady dealer and it has water in it…
 

MisterBill2

Joined Jan 23, 2018
18,934
REALLY, getting a much higher voltage for the spark, with a much faster rise time, will be simple. Invest in a MARK10 CD ignition module, or an equivalent. Use the magnet on the flywheel to charge the battery. 28 KIlovolts was easy and with a slight adjustment we had 30,000 volt sparks. But that is very unforgiving of any flaws or faults in the secondary wiring. A current production CD module is probably what is used on the top-fuel dragsters and should be readily available.
 

Thread Starter

russwr

Joined Aug 29, 2017
62
If you use the magnetron to make a spark, it doesn’t have to be too powerful! On the other hand if you are trying to ignite the fuel using the electromagnetic radiation, I am not sure there is a power level that would work. Of course, if you get your fuel from a shady dealer and it has water in it…
REALLY, getting a much higher voltage for the spark, with a much faster rise time, will be simple. Invest in a MARK10 CD ignition module, or an equivalent. Use the magnet on the flywheel to charge the battery. 28 KIlovolts was easy and with a slight adjustment we had 30,000 volt sparks. But that is very unforgiving of any flaws or faults in the secondary wiring. A current production CD module is probably what is used on the top-fuel dragsters and should be readily available.
Faster ignition with capacitor discharge in microseconds from a CDI unit is not desired. Only wanting milliseconds with the type called inductive ignition which is in vicinity of 8-30 milliseconds.
I may attempt to add 12v battery superimposed on the 5-8v 3 amps from the flywheel north pole magnet inducing into primary coil. The back EMF generated higher than -130 volts would then run the secondary side for higher, high volts ignition. Hall magnetic sensor to run FAST Mosfet 4 amps , resistor current limited, and injected into the Magnetron tab terminal. That terminal is connected to Primary side , but is usually used to shut off mower engine with ground connection. The speed is controlled by the internal solid state trigger embedded in the epoxy, that connects the primary coil to ground for shut off, for the milliseconds pulse output..
 
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Ya’akov

Joined Jan 27, 2019
9,230
Faster ignition with capacitor discharge in microseconds from a CDI unit is not desired. Only wanting milliseconds with the type called inductive ignition which is in vicinity of 8-30 milliseconds.
I may attempt to add 12v battery superimposed on the 5-8v 3 amps from the flywheel north pole magnet inducing into primary coil. The back EMF generated higher than -130 volts would then run the secondary side for higher, high volts ignition. Hall magnetic sensor to run FAST Mosfet 4 amps injected into the Magnetron tab terminal. That terminal is connected to Primary side , but is usually used to shut off mower engine with ground connection. The speed is controlled by the internal solid state trigger embedded in the epoxy, that connects the primary coil to ground for shut off, for the milliseconds pulse output..
No—we were talking about using a magnetron, which is not the same as a magneto—what you are talking about.

A magentron is a vacuum tube that uses magnets in stead of a grid to control electron flow. They happen to be very well suited to producing microwave radiation and are used in microwave ovens.

A magneto is a primitive generator used in internal combustion engines along with an ignition coil to make the spark for the engine.

Magneto is the word you want.
 

geekoftheweek

Joined Oct 6, 2013
1,240
Briggs and Stratton have used the Magnetron name for their ignitions for years. It is a magneto based system, but it is called Magnetron.

Everything I have ever read says placing a voltage on the shut off wire will damage the unit. It is not designed to work that way.
 

Thread Starter

russwr

Joined Aug 29, 2017
62
No—we were talking about using a magnetron, which is not the same as a magneto—what you are talking about.

A magentron is a vacuum tube that uses magnets in stead of a grid to control electron flow. They happen to be very well suited to producing microwave radiation and are used in microwave ovens.

A magneto is a primitive generator used in internal combustion engines along with an ignition coil to make the spark for the engine.

Magneto is the word you want.
The questions posted had to do with the common lawn mower engine. Before 1982 the Briggs and Stratton brand ignition coils had a plain autotransformer , that collectively was called a magneto. That was used in conjunction with what was called points switch and condenser capacitor. The revolving flywheel used an outside north pole magnet to operate the system. After 1982, an interim temporary time period , a removable solid state trigger module was added to the transformer as an option only . After a few years the Briggs Company ignition coils were embedded in epoxy with the Briggs brand solid state trigger, to operate the ignition. Those then and now in our time, are called MAGNETRONS. That means it is the same autotransformer with 3 terminals, with the now solid state trigger built in. The same flywheel magnet is still used. The household Ghtz microwave oven has a glass radiation tube that also just happens to have the same name magnetron. The English language has several words that have dual and triple meanings, that at times, can be confusing to others.
 
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MisterBill2

Joined Jan 23, 2018
18,934
The questions posted had to do with the common lawn mower engine. Before 1982 the Briggs and Stratton brand ignition coils had a plain autotransformer , that collectively was called a magneto. That was used in conjunction with what was called points switch and condenser capacitor. The revolving flywheel used an outside north pole magnet to operate the system. After 1982, an interim temporary time period , a removable solid state trigger module was added to the transformer as an option only . After a few years the Briggs Company ignition coils were embedded in epoxy with the Briggs brand solid state trigger, to operate the ignition. Those then and now in our time, are called MAGNETRONS. That means it is the same autotransformer with 3 terminals, with the now solid state trigger built in. The same flywheel magnet is still used. The household Ghtz microwave oven has a glass radiation tube that also just happens to have the same name magnetron. The English language has several words that have dual and triple meanings, that at times, can be confusing to others.
Certainly the usurping of a name of a device, (magnetrion) as a trade name for a totally non-related product is at best lazy thinking and at worst just plain stupid. But the taking of cool sounding words by the illiterate has been happening for so long that it does not seem to bother a lot of people.
But as an individual who had to write sales letters and descriptions for what was in contracts and what was not in them, I had to be very careful about words and what they mean. When words mean many thousands of dollars they do become rather important.
As for the spark system, there are packages called "Multi Spark Discharge" that do produce a spark that lasts quite a few milliseconds. I have not investigated them because the "MARK10" system was very adequate to fire both lean and rich mixes very well.
 

LowQCab

Joined Nov 6, 2012
4,192
Please re-read my Post #2 .
Spark-Voltage is ONLY determined by Spark-Plug-Gap and Compression-Ratio, ( Cylinder-Pressure ), Period.
Everything else is just advertising-hype or BS.

You will NOT increase Horsepower by modifying the Stock-Ignition-System in any way.

Not even a tiny-bit, not ever.
You "might" increase Power by way of other Substantial-Engine-Modifications,
which "might", subsequently, require a more powerful Spark ............. sometimes,
depending, of course, upon the character, and the extent, of the Modifications,
and how much the Cylinder-Pressure is actually increased over stock levels.

( an "extended-tip" Spark-Plug "may", very-slightly, increase Power, but not in every case ).
( make sure that the "Heat-Range" of the Plug is high enough to keep the Tip clean under all conditions )

Any changes that "could" actually, or possibly, or maybe, or kinda-sorta, increase Power-Output are
not allowed by the Rule-Book in Organised-Kart-Racing,
( if that's what You are pursuing, and You are also running in a "Stock" Class ).

Power increases can not "fix", or "cover-up", other very important factors required for winning races.
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