ThierryT. the three main ways heat energy is transferred is by:
radiant
conduction
convection
You can search these up in Internet explanations. Read these in secondary school general science books.
Observe and experience them in real life. How you dress. How others conserve inner heats.
Radiant is across a distance of energy flow from more heat to any and all less heat.
The “thin light sheet (of metal)” will block and interrupt radiance heat transferring. First that plate will have to absorb the received radiance energy. Heat itself. To the re-radiate it out the other plate side.
Kristijan in the recent past defined the very best charcoal gasifier hearth systems energy loss conserving . . . the surrounding wood charcoal itself. It will block all three ways of heat loss outwards.
Ha! Consumed up then the extreme HOT, HOT oxygen active charcoals glowing core will become externally apparent.
Practical use safety says to one sheet, maybe even a gapped two sheets cover the outsides for touch safety.
Hammer this into your understandings.
Raw wood gasifiers are always heats deficient. And can always benefit from any external added heat energies. Into the let in air. Into the fuel stack. Around the mid and lower gasifier hearth core.
Wood charcoal system are always heat excessive. (You created this by driving off all of the cooling water and HC’s chain volatiles converting to just a refined charcoal.)
Charcoal fueled system you are always fighting materials killing excessive heat. This excessive internal heat all too easily melts the remain cell wall minerals. A charcoal system loves to make flow clogging clinkers.
And how Sir do you dress yourself now we are going colder?
Gapped layers to be able to adjust for your variable internal heat making activities?
Or thick dressed, sweating?
Regards
Steve Unruh
What Steve sayd.
l am a creature of intuition and while Conduction and Convection are simple to experiance in real life, Radiation can be eluseve. DO NOT disregard it! It is extremely important once we get in to just above room temperature zones. This was my mistake snd many of -my in the trunk- designs failed because of this. I got double, triple walls built with no thermal bridging, air gaps, the whole deal. but l disregarded the radiation…
I only learned about radiation when one day walking around my brick layed stove. Same room, same air temperature, but parts of the room felt much hotter thain others. Closer examination showed this effect to be much more obvious thain l thod.
Hi Giorgio, i believe this means ampere-windings, a calculation for transformers, electromagnets and stuff, meaning few windings= a lot of amps, many windings=fewer amps.
With just one winding, one turn you need 80000 amps to get enough magnetic force.
I maybe remember this totally wrong, but it could be found on the net.
Giorgio, you actually need to achieve a high magnetic field density in the iron core of the coil, you probably intend to wind the coil with a 2.5mm2 copper wire. This cross-section of the wire is capable of carrying an electric current of up to 50A for a short time, but now we have to calculate the length of this wire, which would represent the appropriate resistance at a voltage of 12V,… and the result is 35m. If you intend to make two coils, let’s take iron with a diameter of 30 mm and a length of 200 mm as the core, we would wind two layers of coils, or about 150 coils for each coil, this will make a very strong magnet, the attractive force will probably be greater than 100 kg.
göran,tone, thank you for helping…
i have two wires with each 5 meters lenght
is it right when the windings on the cores run around in the same direction(how i have made)
, or must be winded in opposite direction?..for receive north and south pole on the upper part?
Giorgio, the magnetic current must work in the same direction, test this by making the two iron cores attract each other, thus the magnetic field density will double, but if we place them in such a way that there is a repulsive force between them, the magnet of the first coil will neutralize the magnet of the second and not will have no effect on the permanent magnet. If you plan to connect a 10 meter long wire to 12V, use an iron wire resistor that you use for welding, …
Or: if you accidentally come up with a monopolar magnet, you never need wood, charcoal, or electricity again…
Sorry, joking, but if you do, please share it with us woodgassers
i have made a drawing…
every leg of the electro magnet has a inner coil and a outer coil ( the outer coil is designed besides for understanding better).
now the connection of the coils…is it right, when i connect the end of the first -1- outer coil with the begin of the second-2- inner coil…?
besides that i am a learned furniture maker, i wonder if at school during physic lessons i have dreamed or the teacher was unable…!!!
good i have here my mentors, dr. göran and prof. tone !!!
I tried to draw how two coils should be connected, for a better idea, imagine one coil, which you cut in the middle and rotate by 180°,… I think it will be understandable
tone, i have yet not understand where the second windings on the same leg goes…
in the video up from the svedish guy he showed that he makes more windings on one round iron leg, up and down and up again and than down again, so he has the 2 wire ends at the bottom…
i have found only 5 meters lenght of copper wire for one leg, so i winded 2,50 m up and than 2,50 m down, so i have also both ends of the wire in the bottom…
in the video is not shown how he has winded the other leg, but also there all both wire ends are in the bottom.
so on my drawing the winding besides the leg in reality is on the leg and goes down…how in the video…i am confused
Giorgio, it doesn’t matter if the wraps are lined up or down, because usually the coils are wound in several layers, it only matters in which direction the electric current flows around the iron core, if you look at my sketch, you can see that in the left winding the electric current circulates in right direction around the iron core, and in the right winding it circulates in the left direction. The easiest way to find out the correct binding is to connect the wires arbitrarily and connect the binding to a low voltage, if there is an attractive force on the piece of iron, you have the correct binding, but if there is no magnet, change the terminals for the beginning and end of one of the coil
thanks for help again…yesterday evening i made some drawings…
simple long rod with one winding ( straightened horseshoe magnet)
than thought divided with two winding layers…
so it should be right…two equal winded parts, than when connected with the bottom iron, one piece must be upside down, how tone explained, and than connected as on the drawng…
is there a difference in the coil windings if a magneto is for 4 cylinder engine or for 2 cylinder engine?
it is from the same company - marelli-,same design, only the capacitor has different value i have seen…
if it is the same coil maybee i can use for spare part…
thanks giorgio
I only know that SEM magnetos has the same windings for 2, 4 and 6 cylinders.
And Kristijan is correct, the capacitors just charge a fraction of it’s value, and a 4 cylinder needs to charge faster.
Kristjan, Goran, here I cannot agree with you, if we try to understand the function of the capacitor in the ignition circuit, we see that it is actually connected in parallel with the interrupting switch, that means that when the switch is closed, the electric current from the coil, flows directly to ground, at the moment when the switch breaks the contact, the entire voltage of the coil appears on the terminal of the capacitor. This moment means the start of charging the capacitor, well, the capacitance of these capacitors is very small, as it has to be, because this is the only way to get a rapid change in the electric current of the primary coil and with it also a change in the density of the magnetic field, which means the induction of a high voltage on the secondary coil. The capacitor actually takes over the “braking” of the electric current when the switch opens the contact, so no arc is formed between the contacts, and the electric current stops very quickly and “softly”, even more, the capacitor also drives the current back in the opposite direction, so the change in the magnetic field is even greater and the result is a very strong spark on the spark plug. The operating time of the capacitor is very short and does not represent an obstacle, so it easily scratches an engine with ten cylinders and high revolutions, an engine with four cylinders and 2000 rev/min. is a “small joke” for electrical elements.
The capacitor would have to hold more charge for a 4 cyl then the 2 cyl because the magneto is turning/charging at the same rate but it is discharging twice as much. You can probably get away with using the same cap from a 4cyl on a 2 cyl, but it will introduce more drag on the engine because it can hold more charge thus more work to charge.
If you can’t test the capacitor, just replace it. They can get ‘weak’ and they aren’t usually very expensive and easy to replace. If you have the specs for the capacitor (which is typically printed on the cap), you can order from an electronics shop and not pay the ‘branded’ mark up because SEM or whoever probably didn’t actually make the capacitors in the first place. Most likely a newer one will be smaller because they got better at making them.
