I bought a handfull in a flee market, unfortunately most of them except 2 are "12V rated and then inapropriate. I try to find a way to wind 5000 loops easely with 15/100 wire
The double frequency is from the way the coil and magnet work. The voltage is the change in magnetic flux / time as seen by the coil. This is zero if the magnet is fully inside the coil, and maximum when entering and leaving. It is also zero when the magnet is at maximum outside the coil. So you get 4 peaks in voltage, 2 positive, and 2 negative voltages. This is 2x the frequency of the piston.
Have just replicated your setup. Used a motor, flywheel, reciprocating magnet, coils(2 different). Effect is from magnet/coil position. Trace is 'cleanly' double freq when magnet oscillates centred on coil. The field lines around the magnet exit on the leading face, spread around the outside and re-enter the back face. Only leading lines travelling outwards cut the coil first (+) then both (0V) then trailing lines only (-) then it reverses direction +,-. Sound plausible? Nice sig gen btw.
I guess both the number of turns, length of coil and moreover the void between magnet and inner diam will have a great incidence... The coil there is a 8W 220 V 600ohm (a specialist could probably guess the number of turns).
I believe there is too much space between magnet and inner diametre...
But then I just watched again with the volume turned up higher, can't hear any change in pitch, so perhaps it is not running at 2nd harmonic. I hope there are some more ideas posted by others. -Mike
the pitch is changing when the coil is put in place but the decrease is 10% more or less... The coil is a "220V 8W Lucifer Coil" swiss made but I don't know if it is the appropriate characteristics!
Thanks again for watching and for your beautiful engines' videos.
Thanks for your comment in reply, however the compliment on the beautiful engines should go to Jos de Vink. We have a similar name, but I have not built anything interesting yet.
Very interesting. My guess at answering your question is that the natural resonace with the magnet outside the coil is 25hz with a longer amplitude of oscillation. When properly located within the coil the magnetic induced load dampens the amplitude and the system settles to a second harmonic, twice as fast but half the amplitude. Great Work! -Cheers Mike
oh, no problem :)
My Dremel does 5000 RPM on the slowest setting.
In 60 seconds it is ready :D
If you let me know what size you need, I can try to make one for you?
Richard
electrique527 2 years ago
Hi again,
the coil, where did you get it from?
Richard
electrique527 2 years ago
I bought a handfull in a flee market, unfortunately most of them except 2 are "12V rated and then inapropriate. I try to find a way to wind 5000 loops easely with 15/100 wire
lecorfec 2 years ago
Search youtbe for
"5K10.20 - Induction Coil with Magnet"
electrique527 2 years ago
see the video on coil and magnet here on Youtube:
watch?v=h1S-lXtIhQ0
electrique527 2 years ago
The double frequency is from the way the coil and magnet work. The voltage is the change in magnetic flux / time as seen by the coil. This is zero if the magnet is fully inside the coil, and maximum when entering and leaving. It is also zero when the magnet is at maximum outside the coil. So you get 4 peaks in voltage, 2 positive, and 2 negative voltages. This is 2x the frequency of the piston.
:-)
V = dPhi / dT ....
electrique527 2 years ago
Have just replicated your setup. Used a motor, flywheel, reciprocating magnet, coils(2 different). Effect is from magnet/coil position. Trace is 'cleanly' double freq when magnet oscillates centred on coil. The field lines around the magnet exit on the leading face, spread around the outside and re-enter the back face. Only leading lines travelling outwards cut the coil first (+) then both (0V) then trailing lines only (-) then it reverses direction +,-. Sound plausible? Nice sig gen btw.
mowerofdoom 2 years ago
Thanks!
What were the characteristics of your coil?
I guess both the number of turns, length of coil and moreover the void between magnet and inner diam will have a great incidence... The coil there is a 8W 220 V 600ohm (a specialist could probably guess the number of turns).
I believe there is too much space between magnet and inner diametre...
lecorfec 2 years ago
Nice work. Very interesting. Lots of thoughts but not enough space in this little box to write them all down!!
I will dig out my MkIV engine and try to repllicate your work this afternoon.
Back soon!
mowerofdoom 2 years ago
But then I just watched again with the volume turned up higher, can't hear any change in pitch, so perhaps it is not running at 2nd harmonic. I hope there are some more ideas posted by others. -Mike
mjdevink 2 years ago
the pitch is changing when the coil is put in place but the decrease is 10% more or less... The coil is a "220V 8W Lucifer Coil" swiss made but I don't know if it is the appropriate characteristics!
Thanks again for watching and for your beautiful engines' videos.
lecorfec 2 years ago
Thanks for your comment in reply, however the compliment on the beautiful engines should go to Jos de Vink. We have a similar name, but I have not built anything interesting yet.
mjdevink 2 years ago
Very interesting. My guess at answering your question is that the natural resonace with the magnet outside the coil is 25hz with a longer amplitude of oscillation. When properly located within the coil the magnetic induced load dampens the amplitude and the system settles to a second harmonic, twice as fast but half the amplitude. Great Work! -Cheers Mike
mjdevink 2 years ago
cool
SWINGREGORY 2 years ago