Mr. Don, if you look at the third sketch, you can see that the engine sucks gases from the empty area between the outer wall and the perforated drum that holds the coal, this space also extends below the drum, so that gases can also pass through the lower openings and this is not nothing wrong, but these leaks between the disk and the drum will be quickly sealed by ash. Before starting, however, it is always a good idea to remove some ash from the bottom by turning the rotating disc.
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What I notice in 292 drawing is it is more of a simple fire design, gases go straight out and up though the Charcoal that caring ashes into the hopper. The later drawing is more of a cross flow design with the gases forced to go to the sides where the Charcoal is only contained in the inside of the screen diameter area, this is a little different than the simple fire design giving a place for the ashes to fall out on the outside of the screen to the bottom area free of Charcoal. I feel there is less drag of gas velocities of vaccum formed by moving the gases to the side and up and out of the gasifier keeping the ashes from collecting into the charcoal hopper fuel area and then being contaminated with ases and burned again. This might be why slag is formed around the nozzle and builds up so fast in a simple fire design.
I especially like Tones design of the ash disk floor below the nozzle with holes in it and a rototating disk to open and close the holes for ashes drop though to be cleaned out. This is very nice with out having to empty the entire gasifier out to clean out.
This is the one thing I did not like about my down draft cross diagonal flow gasifier. The time consuming of having to clean it out after it had cooled down cold, after a few hours of running time because of ashes plugging up the hot lobe burn area.
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stopped by a flu since 2weeks work has not gone forward…we found that the magneto is very weak , makes only a very little spark from the high tension point to the housing…on the spark plugs arrives nothing…now begins the adventure of remagnetizing…i hoped i must not do this, but on the other side it will be shure important to be able to remagnetize the own magnetos…found also a video from a magneto. where the magnets turns with the rotor, how also my model is…in the video they charge the magnet from outside without dismantling the whole unit…they say 60 to 80 % magneto refreshing with this method
i have some pages about my magneto model, unfortunately in french language…are some of our french forum members able to translate in english??
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Hi Giorgio, if your magneto got rotating magnets, they are often modern types, AlNiCo and others, they are often very strong even if old (could be others, more sensitive)
As these magnets are very stable, they are also very hard to re-magnetizise, we talking an old welding transformer rebuilt to a electro magnet, and maybe big capacitors discharged througt it, or, many car batteries in series= firework!
I could ofcourse be wrong, but. Maybe a bad secondary winding is the culprit? Often the trouble, hard to measure, often a complete circuit, but not under load, this are the most troublesome problems with magnetos-hair thin copper wire, up to 15000 turns, turn beside turn, no crossing or overlapping.
The condenser (capacitor) also often get bad, because of age, but easy to replace with a better, modern one.
Smokstak forum got some good info on magnetos, and links.
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First of all, it is necessary to check how strong the magnet is, maybe Goran is right that the cause of the bad spark is the high-voltage winding. Place the rotor with the magnets in position between the iron core and test the strength of the magnetic field by trying to lift the iron core of the coil which is demountable, measure the resistance of the high voltage winding and compare this to the resistance of the working winding on the Acme motor, I think it is a very similar coil , the resistance is usually a few kilo Ohms.
There is also the possibility to upgrade an external ignition coil, which feeds the primary winding of the original coil. The capacitor during ignition plays an important role, it reduces sparking between the contacts of the circuit breaker, because the moment the contacts open, the electric current flows into the capacitor, which is quickly charged, to a rather high voltage, well, that’s how the electric current in the circuit stops, the next one momentarily, the capacitor discharges through the coil in the opposite direction, and this is repeated several times. The result of this is a rapid fluctuation (oscillation) in the circuit, which causes, in addition to the first - a strong breakthrough of the spark between the contacts of the spark plug, additional maintenance of the plasma “fire” …,.
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I agree what Tone said, one simple test of the magnet would be to test if it’s strong enough to lift, say: a medium/bigger size screwdriver, this is a very “stoneage” way to test, but gives some idea about it’s strenght.
Like the old “rule of thumb” where small flywheel magnets should be able to lift themselves (the flywheel hanging from a piece of iron/steel)
And what i’ve heard on these type magnetos, the capacitor are more important than in other ignition systems, it needs to exactly quench the arc, in time when the magnetic field is on it’s “top” before it gets lower and collapses. If i remember correctly it’s a german word: abriss that defines this. More important the smaller the radius of the rotating magnet or armature.
My favourite way to test condensers (ignition capacitors) is to use an battery powered ohm-meter, MUST BE AN “old” NEEDLE SCALE type, no digital, set it on highest scale, megaohm, have the condenser out of circuit, fast put the probes to conds poles, meter should show a almost not noticeable reading and slowly go back to zero. Shift polarity fast, now it should give a slightly higher reading, and dip back to zero.
This gives a very good test of the cond’s “health”, can be repeated with cond heated to around 70°c to simulate working conditions.
Next step is to test it with a capacitance meter, this often gives correct readings, but shows not if capacitor is good or bad.
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If we compare the function of the electric current with the flow of water through a pipe and a switch for breaking the circuit, with a valve for closing the water, we can imagine that when the valve is suddenly closed and the flow is stopped, the pressure in the pipe increases greatly and can cause damage to the pipeline (hydraulic shock). , well, if we have an expansion tank installed in front of the valve, it softens the impact shock and then part of the water flows in the opposite direction through the pipe, this wave can be repeated several times. (Ram pump exploits this phenomenon) . A similar function is performed by the capacitor when the electric current is interrupted, let me just mention that the phenomenon of searching between the contacts of the switch during the interruption is a sign of a bad capacitor, this sparking or the formation of an arc means a “slow” interruption of the circuit, a “slow” change in the magnetic field and the result is “bad” voltage induction on the secondary winding - poor spark on the spark plug. It can also be interpreted as sparking between the contacts of the breaker is a loss of induced energy, which is then not obtained at the spark plug.
Goran, I am also with you, from your words it is clear that you have a lot of knowledge and practice in this field.
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göran, tone, thanks for help…
in the french workshop handbook is spoken from remagnetizing the magneto, if magnetism is not enough…so i think it is a old kind of magneto material, what needs from time to time a refreshing…i have ordered a french dictionary, so i can translate something more
on the foto is to see a part of the iron sheet packet around the rotor…so i think this is the point where a magneto refreshing tool is placed without opening the whole apparatus
will try to build a electro magnete from this pieces, this wire from a trafo could work…
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Hi Giorgio, you’re right about the “refreshing points” that is right place to put a horseshoe electro magnet.
Keep in mind you need soft iron, in sheets, to avoid magnetic flux surging, best would be to build it from a trafo core.
Im also wondering if you need to take the coil of before recharging, that jolt probably would induce a lot of amps in the coil, even in a fraction of a second, it could fry the coil?
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Goran, I think that increasing the magnetic field will not harm the coil, if it is not short-circuited, but it is still necessary to dismantle it, so that the magnetic flux ends through the rotor and is not lost through the core of the coil. I would also point out the correct polarity, north-south of the permanent magnets and the polarity of the magnetic field from the electromagnet, the direction of the magnetic field must work in the same direction.
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tone, göran, yes i think more shure is to dismantle all and trying to recharge only the rotor…my son found his old compass again, so i can see the polarity…
i need some time for getting fit again, than the work will continue…
kristijan, this translater is very interesting…must you write the french sentences before or you make it by picture…in the book is a lot of information about failures of the magneto and remedies…
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Correct Tone, but one thing could be a problem with homemade magnet re-chargers, some of them re-magnetizise when the electric field collapses, which tend to recharge the magnet “backwards”, don’t ask me the physics behind this, i’ve noticed it, and talked to others that experienced the same, no real problem, just try carefully, and reverse the polarity.
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Hi Giorgio, be careful with that compass around the electromagnet, when i built mine i tested with a small 9 volt battery, and that was enough to make a compass useless.
One good way is to use a rektangular/bar magnet, test it with compass and mark north and south pole on it, then use it as a “master” or tester, a good marker pen is also very handy in this work, marking every known pole.
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when i make two adapters for the rotor, in a way the rotor stands perfect between, it should turn automatically in the right position when i give a bit current on the electromagnete…adapters not touching too strong for this…??
more up was a video, a half year ago, a swedish guy made it with a horseshoe magnet on a string to find the right polarity without compass…
should also work with a rotor magneto?
for a complete burn out i am in time yet…
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excuse this flashback.
Tone, I am surprised that you do not seem to offer any heat exchanger in your charcoal gasifier schemes. Is this because there is no advantage for these gasifiers to reinject heat energy into their hearth ?
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It is certainly good to return heat energy from hot gas to the preheating of fresh air, this would work especially well with coal gasifiers, since these gasifiers need much more air to operate than wood gasifiers. It is a good idea to surround the hot zone with glowing coals with at least one layer of thin light sheet (reflecting radiation back into the process).
The purpose of this sketch is to show the flow of gasification from the center outwards.
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what do you mean by " with at least one layer of thin light sheet (reflecting radiation back into the process)."
Excuse my insistence, but I don’t understand
Thierry
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a thing i really wonder and not understand…the translation , there is spoken in the last sentence from the use of a magnetizer with 80.000 ampere / windings ???
who has a idea?
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