Perhaps someone can explain the following:
I sat a cylinder neo magnet on top of an air core inductor wound with #10 magwire and noticed it was singing at 959Hz. What is remarkable is that there are actually two tones (possibly 3), the second of which is approximately an octive higher (959Hz & ~1918Hz) and if I tune to either side of the 959Hz the lower tone starts wobbling so there must be two low frequency tones.
The tones are easiest to hear when the magnet is placed on the top of the plastic spool coil form and directly over the winding although I can also hear the tone while holding it in my hand, so the tone is not a result of the vibration of the plastic spool nor is it coming from the winding. I tried various other neos of different size and stength, some of which were rectanglar in shape and the tone did not change. I also tried a ceramic block magnets - tone did not change though it was not as loud.
All this was observed while pulsing the inductor (pw=100us) with the circuit drawing 20ma. If I increase the current by increasing the pulse width the tone gets louder.
Cylinder Neo: dia=1", height=1"
Spool Circumference = 10.984 inches
Spool Diameter = C / π = 3.4963 inches
Spool Height = 7.48 inches
Wire Diameter = 0.1056 inches
Turns/layer = 67
Inductor
Measured Inductance: 3.98 mH
Measured Resistance: 0.395 Ω
Ohms/Kft: 0.998900
Calculated wire length: 395 feet
Resonant Freq: ~100KHz
-Duff
Do you live in the US or the UK?
960 = 60 x 16 so if you are in the US you are probably picking up the mains freq.
You can Hear the tone?
You can hear it audibly without electronic amplification?
How are you measuring the frequency?
What is the frequency of your driving signal?
If you did achieve get the right freq of the magnet , it will start singing it may also amplify the sound of the coil , since if the magnet moves ,this is basically a speaker. So 2 freq the magnet and the generator , like tuning a piano or a guitar , when to freq are close together you will start hearing a third freq this one can only be heard when you have two freq slightly out of tune , the third freq will start to slow down and go out if you get to close , but can also go up to one octave up so double the freq, so that third freq is really special since its like a ghost note adjustable in a really close range of freq .
I believe you did the same with a magnet, make it sing make it sing !
Mark
Quote from: Mk1 on May 27, 2009, 02:50:34 PM
If you did achieve get the right freq of the magnet , it will start singing it may also amplify the sound of the coil , since if the magnet moves ,this is basically a speaker. So 2 freq the magnet and the generator , like tuning a piano or a guitar , when to freq are close together you will start hearing a third freq this one can only be heard when you have two freq slightly out of tune , the third freq will start to slow down and go out if you get to close , but can also go up to one octave up so double the freq, so that third freq is really special since its like a ghost note adjustable in a really close range of freq .
I believe you did the same with a magnet, make it sing make it sing !
Mark
WOW BRO!!
;D ;D ;D
LOVE THE MUSIC!!
IST!
Quote from: TinselKoala on May 27, 2009, 02:29:39 PM
Do you live in the US or the UK?
960 = 60 x 16 so if you are in the US you are probably picking up the mains freq.
You can Hear the tone?
You can hear it audibly without electronic amplification?
How are you measuring the frequency?
What is the frequency of your driving signal?
Yes, the tone is audiable without amplification.
The frequency corresponds to the function generator readout plus I attached a small speaker to the FG output to verify it was the same frequency that the magnet was singing.
If I put a piece of paper under the magnet, I can raise it to about 6" above the inductor and still hear the tone.
Quote from: Mk1 on May 27, 2009, 02:50:34 PM
If you did achieve get the right freq of the magnet , it will start singing it may also amplify the sound of the coil , since if the magnet moves ,this is basically a speaker. So 2 freq the magnet and the generator , like tuning a piano or a guitar , when to freq are close together you will start hearing a third freq this one can only be heard when you have two freq slightly out of tune , the third freq will start to slow down and go out if you get to close , but can also go up to one octave up so double the freq, so that third freq is really special since its like a ghost note adjustable in a really close range of freq .
I believe you did the same with a magnet, make it sing make it sing !
Mark
Mark, I believe you are partially correct.
The paper or plastic spool acts as a diaphragm amplifying the vibration of the magnet. If I take the frequency up the singing follows.
However, there seems to be an inherent frequency, 959Hz, that spans the multiple magnetics I tried and the wobble or beat note seems to reside in all the magnetics.
-Duff
Ah, I think I understand now. You have an inductor--a coil wound of wire--near a magnet and you are driving the inductor with your signal generator at 959 Hz, and you are hearing the magnet/inductor combination "sing". Is that right so far? And you can also hear it singing at integer multiples of this frequency.
Are you quite sure it is the magnet singing, or could it be the coil wiring? Does it sing when suspended or only when sitting on something? Do you have a piezo element that you could tape to the magnet and monitor on your oscilloscope?
At first pass I am thinking you have invented the magnetic loudspeaker, and because that 959 Hz figure is nearly exactly 16 x 60 Hz, your setup is interacting with ambient fields at that frequency, and as you shift your FG slightly, you are hearing the beat notes that Mk1 describes.
Quote from: TinselKoala on May 27, 2009, 05:21:29 PM
Ah, I think I understand now. You have an inductor--a coil wound of wire--near a magnet and you are driving the inductor with your signal generator at 959 Hz, and you are hearing the magnet/inductor combination "sing". Is that right so far? And you can also hear it singing at integer multiples of this frequency.
Are you quite sure it is the magnet singing, or could it be the coil wiring? Does it sing when suspended or only when sitting on something? Do you have a piezo element that you could tape to the magnet and monitor on your oscilloscope?
At first pass I am thinking you have invented the magnetic loudspeaker, and because that 959 Hz figure is nearly exactly 16 x 60 Hz, your setup is interacting with ambient fields at that frequency, and as you shift your FG slightly, you are hearing the beat notes that Mk1 describes.
Yes, I am sure the magnet is singing.
It sings sitting on the top of the plastic spool and it also sings if I put it on a piece of paper and raise it above the spool (up to six inches). The beating freq ceases at 959Hz.
I don't have a piezo handy - will check radio shack...
The question is exactly which ambient fields is it interacting with and how do I prove it.
Here's a pic for better clarity.
-Duff
Edit: It also sings while holding it in my hand close to the top of the inductor though it is very faint.
IT IS SINIGING ....
NOW YOU NEED IT TO RINGGGGGG AS IT TRAVELES ROUND AND ROUND ....
THEN TAP VIA ANY CORE U DESIRE ....
IST!
LOOKS LIKE THE INPUT DEVICE DRIVEING THIS COIL ...
I stuck a radio shack piezo (p/n:273-059) on the magnet and it really didn't provide me any more information. The peizo is producing sine output at ~2.87KHz which is probably its resonant freq. Spec show 2700 ±500Hz.
I can tune for maximum output which occurs at 1007Hz but that not what I'm after....
-Duff
Quote from: duff on May 27, 2009, 08:50:30 PM
I stuck a radio shack piezo (p/n:273-059) on the magnet and it really didn't provide me any more information. The peizo is producing sine output at ~2.87KHz which is probably its resonant freq. Spec show 2700 ±500Hz.
I can tune for maximum output which occurs at 1007Hz but that not what I'm after....
-Duff
I was hoping the piezo would show the magnet's oscillations but apparently not, or the impedance match is poor...I suppose you are confident of the calibration of your counter...
Anyway, if your mains frequency is 60 Hz like in North America, that's so close to 959/16 that it is very suggestive of a power line resonance.
If you can somehow power your apparatus outside somewhere, far from overhead transmission lines, you could see if the 959 Hz ringing and the beats are still there. Or you could examine your lab space with a good EM detector like a Tri-Field Meter, and see if you have unusually strong mains radiation there.
@duff
I'm sure you've seen this....
http://video.google.com/videoplay?docid=5540717206741162529
The frequency highlighted on the video isn't the only one of interest. 959.4 is one of many that can be interesting. In each frequency's case the magnet size, shape and strength have almost no relationship to the frequency.
Hi Duff,
IF you have an oscilloscope at hand, you could plug in a a few feet of wire to its input, no ground is needed and use the scope as a kind of field strength meter, I am sure you know what I mean. You may even use the 10:1 probe as a pick up antenna if you clip to its "hot" pin a piece of wire and the ground clip is floating.
This way you may find a "signal" of high amplitude, unfortunately your mains frequency sinusoidal signal (50 or 60Hz) will possibly rule on the display. If so, maybe you could use some Faraday shield around your coil + magnet setup to see if this effect reduces.
rgds, Gyula
@Gyula
The signal you will see with an antenna will be primarily electric. The same for any effect from house or grid wiring. A very large air core winding would be more telling. A Hall-Effect probe would show more, provided it can handle the frequencies in question.
Of course, putting the whole thing in a Faraday cage will also tell you something.
My guess is the cage will do nothing to the effect.
@duff
If another spool of wire is available, try it. You should see the singing tone will change with the resonant frequency of the spool and not the change in magnets. Just use spools of air core. I'm not saying the tone is relative to the spool. It should be relative to the magnet as an affect from the spool field. Confused yet?
BEP
@duff
i like to ask you something
did you get the SPINING EFFECKT > LIKE JET ENGINE TURBINE ;)
I THING THE MAGNET FOR <S.M> DEVICE IS FOR TO GET SPINING MAGNET FILD LIKE GENERATOR
I THING THE POINT FOR SINGING OR VIBRATING THE MAGNET FILD FROM NEO IS NOT <TPU> LIKR S.M
IF I SEE DEPER IN MEANING WHAT IS THAT SPINING LIKE A JET TURBINE INSAID THE TPU
THE RESOLTS IS THE <.... FROM TPU STEVEN HAS ALLWAYS GET FROM HIM <DC VOLTAGE
BEACOUSE YOU MAY SEE WHEN HE SAY SPINING
SPINING IN ONE DIRECTION IS ABLE TO PRODUCED <DC VOLTAGE
THAT IS THE WAY TO GO AND HOW TO MAKE
NO SINGING
FORM SOME MAGNET
THE ATHER TPU
WHIT PUTING THE TV AND DRILL TO HIM
..
THAT TPU IS HAVE 5000 HZ THAT IS AMAZING IMAGEN THAT SPEED OF LET SAY SOME DC GENERATOR TO SPIN 5000 TURNS JUST IN ONE SECOND
YOU AMY ASK AND THING IF THE ELKTROMAGNET HO IS SPINING THERE IS NOT TO BE NEED TO BE BIG ONLY VERY VERY SMALL ELKTROMATGNET WHIT THAT KIND OF SPEED WHILL BE ABLE TO PRODUCED INCREDEBLE POWER
I LIKE TO POINT LIKE S.M SAYS TO < MANNIX MOVE SMALL MAGNET WHIT SPEED LIKE A GUN BULYTH
BUT IS HARDEST TO EXPLANE HOW IS ABLE SOMETHING TO SPIN WHEN WE PUT 5000 HZ OR LESS OR MAYBE MORE
HOW TO SPIN AND FINALY RESOLTS TO HAVE <DC VOLTAGE
I
HAVE MAKE MAY SOLUTION DIDI YOU GET SOME NOW IS TIME TO MAKE SETUP AND WORKING DEVICE
THANKS FOR ALL FRIEND HERE HO HAS READING THIS
I
@Mark
I placed the circuit in a Faraday Cage made of aluminum screen, 34"x20"x34", which was grounded to a ground rod. Cable length to ground rod was about 3 feet.
I know a copper cage would be better but that all I have at the moment. The aluminum should have attenuated the signal some.
Anyway it made no difference. Still have the fantom signal.
BTW: Yes, I'm confident in the FG readout (considering resolution), it matches the frequency counter in my scope.
@Bep
Yes I have seen Marco dancing magnets. I find it interesting that you stated that 959.4 where as I only mentioned 959Hz. To be precise the signal is in fact 959.4 Hz.
Last night I was thinking that the only other thing constant outside the driving signal is the resonant freq of the coil. So I tried putting a 4.37nF/3KV cap in parallel with the inductor. The 959.4Hz remained unchanged.
@Gyula
I've looked at the inductor signal and its a little difficult to describe some of what I've seen. I did try Bep's suggestion of using another air coil but that seemed to introduce more factors however I could see peaks slowly up and down when I am to either side of the center freq. and at center the movement stops.
Below is a scope shot of the probe alone beside one of the leads to the inductor. The driving circuit consist of two irf840 in parallel and driven by a mic4420 (6A driver).
I find it interesting that the ringing is at 35.714 KHz.
Steven Mark states: "I made an amp and had a really difficult time with a 35K resonance I ad so much trouble with it that I finally left the resonance there. I last measured it at 35.705K at a really high level."
I've order some ratiometric linear hall effect sensors (A1322LUA-T) that will be in next week. Maybe they will shed more light on this.
-Duff
Quote from: MACEDONIA CD on May 28, 2009, 02:04:22 PM
@duff
i like to ask you something
did you get the SPINING EFFECKT > LIKE JET ENGINE TURBINE ;)
I THING THE MAGNET FOR <S.M> DEVICE IS FOR TO GET SPINING MAGNET FILD LIKE GENERATOR
I THING THE POINT FOR SINGING OR VIBRATING THE MAGNET FILD FROM NEO IS NOT <TPU> LIKR S.M
IF I SEE DEPER IN MEANING WHAT IS THAT SPINING LIKE A JET TURBINE INSAID THE TPU
THE RESOLTS IS THE <.... FROM TPU STEVEN HAS ALLWAYS GET FROM HIM <DC VOLTAGE
BEACOUSE YOU MAY SEE WHEN HE SAY SPINING
SPINING IN ONE DIRECTION IS ABLE TO PRODUCED <DC VOLTAGE THAT IS THE WAY TO GO AND HOW TO MAKE
NO SINGING
FORM SOME MAGNET
THE ATHER TPU
WHIT PUTING THE TV AND DRILL TO HIM
..
THAT TPU IS HAVE 5000 HZ THAT IS AMAZING IMAGEN THAT SPEED OF LET SAY SOME DC GENERATOR TO SPIN 5000 TURNS JUST IN ONE SECOND
YOU AMY ASK AND THING IF THE ELKTROMAGNET HO IS SPINING THERE IS NOT TO BE NEED TO BE BIG ONLY VERY VERY SMALL ELKTROMATGNET WHIT THAT KIND OF SPEED WHILL BE ABLE TO PRODUCED INCREDEBLE POWER
I LIKE TO POINT LIKE S.M SAYS TO < MANNIX MOVE SMALL MAGNET WHIT SPEED LIKE A GUN BULYTH
BUT IS HARDEST TO EXPLANE HOW IS ABLE SOMETHING TO SPIN WHEN WE PUT 5000 HZ OR LESS OR MAYBE MORE
HOW TO SPIN AND FINALY RESOLTS TO HAVE <DC VOLTAGE I HAVE MAKE MAY SOLUTION DIDI YOU GET SOME NOW IS TIME TO MAKE SETUP AND WORKING DEVICE
THANKS FOR ALL FRIEND HERE HO HAS READING THIS
I
Mac,
Yes, I agree the singing magnet is not like the TPU.
I have not tried to get the spinning effect yet. I'm trying to figure out what is causing the 959.4Hz signal related to this vibrating magnet. Perhaps it is a clue.
-Duff
@duff
If you have not all ready done so, run your FG up to 35.714k. If your magnet screams around 4800Hz then your test is singing the same way my last TPU is.
Quote from: BEP on May 28, 2009, 05:28:20 PM
@duff
If you have not all ready done so, run your FG up to 35.714k. If your magnet screams around 4800Hz then your test is singing the same way my last TPU is.
I wouldn't be able to hear anything at that freq. - have a high freq. hearing loss.
I did run FG up to that freq and tried. My ear lobe felt some vibs but I didn't hear a thing :)
Make a small coil to go around your magnet. You should be able to 'hear' it with your scope ;)
I suspect it will be approaching 4900Hz.
I'm really surprised you are seeing these things with a metal coated magnet AND you had less amplitude with a non-coated magnet (assuming your ceramic was not coated).
Edit:
I suggest your put a resistor across that coil suggested. Don't connect your scope probe to the open coil.
Just checked my suggestion on mine.
The coil around the magnet must not be tightly wound on the magnet. About a 4mm gap between the coil and magnet should work. But then, I'm using much weaker ceramics.
Just remember, my singing TPU is nothing more than a good weird noise maker. I hope you can do something more with your work.
@Bep
I tried 90 turns of #30 magwire around a chem-wik spool which fit snuggly over the neo. I only got about 3Vpp output and was only able to see the pulses/ringing. I did not see the 4900Hz signal when tuned to 35.714KHz nor could I see the two interacting signals at 959Hz, again just pulses/ringing.
Were you able to see the 4900Hz on your setup?
Also, above you said that 959.4 is one of many that can be interesting.
Would you care to elaborate??
-Duff
Edit: I will try a creamic mag and see if that makes any difference.
Hi , you could try to put something soft under the magnet to stop the vibration , to make sure it is not the coil magnet action , pretty much all coil sing at some freq , when they are not waxed .
Mark
hi to all
@duff
i have read this but is no NEED TO PUT CAGE OF ALUMINIUM OR COPER TO PROVET OF SOME OUT ENERGY FOR THIS
BEACOUSE YOUR FREK . FROM COIL IS TO LOW <959 HZ>
AND CAGE IS NO ABLE TO STOP OUT SAID EFEKCT OF YOUR COIL
IF YOU HAVE SOME BIGER FREK OF YOUR COIL THEN CAGE WHILL BE NEED LIKE
150KHZ OR MORE
WHIT THIS YOU WHIL NO PROVING IS THERE NO EFFECKT FROM OUT SAID
I LIKE TO SAY AND YOU MAY TRAED TO GET IN SOME PLACE WHERE IS NOT ENY KID OF CABLE OF POWER SOURCE
LIKE IN MOUNTING AND THERE TRAED THIS
BUT FOR MY PROVING YUO WHIT YOUR MAGNET ONLY INCREASING INTERACKTING FILD FROM SOME POWER LINE AND YOU HAVE RESONANCE FROM THAT POWER LINE OF SOME CABLE
THE S.M TPU HAVE VERY FAST SPINING ONE DIRECTION SMALL ELKTROMAGNET FILD
THAT IS THE ANSFER
Quote from: duff on May 29, 2009, 12:55:25 AM
@Bep
I tried 90 turns of #30 magwire around a chem-wik spool which fit snuggly over the neo. I only got about 3Vpp output and was only able to see the pulses/ringing. I did not see the 4900Hz signal when tuned to 35.714KHz nor could I see the two interacting signals at 959Hz, again just pulses/ringing.
Were you able to see the 4900Hz on your setup?
Also, above you said that 959.4 is one of many that can be interesting.
Would you care to elaborate??
-Duff
Edit: I will try a creamic mag and see if that makes any difference.
On my OpenTPU attempt I have two areas where each has two rectangular magnets, one above the other. Even though all four magnets are the same, one side sings around 4880 and the other ~3000. I was trying to match an FFT. of video audio.
There was an 1800 spread between the two signals. That spread was segmented by 5 - 200Hz peaks. Those 200 peaks seemed to be the result, not the injection.
Well, the relationship of the signals is not correct so now I have a noise maker.
Metal coated mags suffer heat problems more easily when the right freeks are found.
The singing frequency seems to be a function of the magnet strength, coil specs and coil excitation. All of these frequencies I've found are multiples of Marco's dancing mag freek. The problem is very few of these multiples work. 959.4 is one.
Quote from: MACEDONIA CD on May 29, 2009, 05:39:55 AM
hi to all
@duff
i have read this but is no NEED TO PUT CAGE OF ALUMINIUM OR COPER TO PROVET OF SOME OUT ENERGY FOR THIS
BEACOUSE YOUR FREK . FROM COIL IS TO LOW <959 HZ>
AND CAGE IS NO ABLE TO STOP OUT SAID EFEKCT OF YOUR COIL
IF YOU HAVE SOME BIGER FREK OF YOUR COIL THEN CAGE WHILL BE NEED LIKE
150KHZ OR MORE
WHIT THIS YOU WHIL NO PROVING IS THERE NO EFFECKT FROM OUT SAID
I LIKE TO SAY AND YOU MAY TRAED TO GET IN SOME PLACE WHERE IS NOT ENY KID OF CABLE OF POWER SOURCE
LIKE IN MOUNTING AND THERE TRAED THIS
BUT FOR MY PROVING YUO WHIT YOUR MAGNET ONLY INCREASING INTERACKTING FILD FROM SOME POWER LINE AND YOU HAVE RESONANCE FROM THAT POWER LINE OF SOME CABLE
THE S.M TPU HAVE VERY FAST SPINING ONE DIRECTION SMALL ELKTROMAGNET FILD
THAT IS THE ANSFER
I agree with you about the faraday cage. I need to rule out the 60Hz power line so I am going to try to find an area, maybe an 1 or 2 hours out of the city, where I can rule out that interference.
@BEP
I tired wrapping on half of a ceramic magnet with magwire and though the signal was somewhat different I still could not observe the 4900Hz when tuned to 35.714KHz.
-Duff
@DUFF OK FIND PLACE AND SEE WHAT WHILL BE IF YOU HAVE SOME PROBLEM IM HERE TO FIND SOLUTION ;)
BUT I SAY AGAIN MAST BE HAVE EFFECKT OF SPINING THE FILD
I have been delayed in running the test.
I'm having to build an oscillator that will run on 12VDC.
@duff
There is one possibility I can think of that could create similar results to mine.
Your plated magnet is likely plated in nickel. Nickel is highly magnetostrictive in action. All it would take is a strong pulsing perpendicular magnetic field to the magnet's field.
Ceramics also have some nickel in them.
If this is the case then a form of SAW (Rayleigh wave) may be happening and your shiny magnet may explode under extremes :o
The only way I could understand this working is if the field from the coil was causing the magnet field to drop below saturation. If so, it would only work with one polarity pulse to the coil.
@BEP
When moved the circuit from a breadboard and soldered everything in place the 35KHz ringing I previously had went away.
Below is the current driver circuit. Everything on the right side of the inductor is not being used. This is Tommey Reed's circuit (with different components). He was driving using to drive a motor with BEMF. I replaced the motor with a dummy load (100Ω resistor).
Do you think the negative 12V in the scope shot would keep from working as yours?
Quote from: duff on May 30, 2009, 05:24:45 PM
@BEP
When moved the circuit from a breadboard and soldered everything in place the 35KHz ringing I previously had went away.
You probably had some unexpected capacitance in the wiring before. Do you have the same singing magnet as before?
Quote
Below is the current driver circuit. Everything on the right side of the inductor is not being used. This is Tommey Reed's circuit (with different components). He was driving using to drive a motor with BEMF. I replaced the motor with a dummy load (100Ω resistor).
Do you think the negative 12V in the scope shot would keep from working as yours?
I'm not using a FG. I have back to back regenerative magnetostrictive oscillators working as a multivibrator.
Quote from: BEP on May 30, 2009, 06:43:26 PM
Do you have the same singing magnet as before?
Yes and the 959Hz signal is still there.
Quote
I'm not using a FG. I have back to back regenerative magnetostrictive oscillators working as a multivibrator.
I was referring to your reference to the one polarity pulse to the coil and questioning if the negative portion of my waveform would interfere with getting similar results as yours.
If I can get the osc together tonight I'll try to take the circuit to the country tomorrow...
Quote from: duff on May 30, 2009, 09:46:35 PM
Yes and the 959Hz signal is still there.
Ahh! Didn't see the pic on my phone.
Quote
I was referring to your reference to the one polarity pulse to the coil and questioning if the negative portion of my waveform would interfere with getting similar results as yours.
I cannot provide a good answer for you on the effect of polarity for your circuit. I will say the magnet coil polarity relationship works only one way with mine. However, the current in my coils is DC with a heavy AC (sine) component.
Polarity does not cross zero. If I reverse the coil drive without flipping the magnets there are almost no interesting results.
There is still a chance your experiment is an interaction with the grid. I'm anxious for you to prove that idea wrong. Too often I've had exciting tests that failed when I went to battery power :)
Run exclusively with ATV batteries and you win.
--giantkiller.
@Duff
I built and tested the exact same setup you have last year and found the exact same phenomena you describe. It took me a while to find my lab notes on this, about 10 pages, LOL. I produced many variations with multiple coils, multiple magnets etc... .I believe some people here are reading way too much into this, the problem is one of perception, you see a stationary magnet on a stationary coil and have concluded there are oscillations coming from somewhere else. I found the secondary oscillations are from loose coil windings,when the coil windings were varnished the oscillations disappear. I am not saying this effect does not show promise I am just saying I found "where" the oscillations were coming from, it is basically standard induction but the motion is on a very small scale which is misleading. Try "tapping" the magnet on the hard plastic of the wire spool with your scope on the leads and you will see what I mean or hit the table the coil is on. It's pretty cool actually, like a massive microphone or speaker coil.
Regards
AC
Doh, double post
-- I know of something relative to this effect as well, back when me and dad were kids a friend and fellow nerd decided to build a speaker. I mean an insanely massive speaker measuring 8 foot by 8 foot into his livingroom wall. The electromagnet was 2 feet in diameter, Im not even sure what kind of power he was pushing through this monster. In any case at full power this thing could literally re-arrange your furniture, LOL. He also said if tuned properly you could hear any conversation in the whole house, I image you could hear the neighbors talking. I thought this was way too cool:)
Regards
AC
Quote from: allcanadian on May 31, 2009, 12:32:32 PM
@Duff
I built and tested the exact same setup you have last year and found the exact same phenomena you describe. It took me a while to find my lab notes on this, about 10 pages, LOL. I produced many variations with multiple coils, multiple magnets etc... .I believe some people here are reading way too much into this, the problem is one of perception, you see a stationary magnet on a stationary coil and have concluded there are oscillations coming from somewhere else. I found the secondary oscillations are from loose coil windings,when the coil windings were varnished the oscillations disappear. I am not saying this effect does not show promise I am just saying I found "where" the oscillations were coming from, it is basically standard induction but the motion is on a very small scale which is misleading. Try "tapping" the magnet on the hard plastic of the wire spool with your scope on the leads and you will see what I mean or hit the table the coil is on. It's pretty cool actually, like a massive microphone or speaker coil.
Regards
AC
AC,
Thanks for the info.
I'm running the osc & driver on DC now and the 959 freq is still there.
I can hold the magnet in my hand above the winding (off the spool) and hear a tone coming from the magnet (domains moving i suppose) and if put my ear to the winding there does seem to be sound there - it's difficult to tell for sure.
The coil windings in my case are not loose for it was tightly wound and the wire very stiff (400' #10 magwire) so I doubt the wire is moving but he domains in the wire in motion.
I did try hitting the coil with the handle of a nut driver and noted no microphonics nor difference in beat tone though it may have been so subtle my hearing couldn't detect it.
Question: When you tried multiple windings did the beat frequency occur above & below the 959Hz in every case??
If the center freq was constant, then I'm wondering why the same frequency is common with windings of different lengths & physical characteristics. I suppose it could be related to the diamagnetic characteristics of copper.
-Duff
I have now determined that the beat tone is coming solely from the inductor.
When I previously placed my head outside the coil I heard nothing.
Tonight I placed my head on top of the plastic spool, over the center, with the magnet removed.
The spool of course has a cylinder center with holes in it ends and sound there is amplified.
What I heard there was two tones and a wavering beat note.
When the magnet is placed on top of the spool it amplifies the affect.
-Duff
Quote from: duff on June 02, 2009, 02:12:35 AM
When the magnet is placed on top of the spool it amplifies the affect.
-Duff
Amplifies?
Weren't there many folks here that determined a magnet had no real effect upon a coil?
Regardless, Nice work @duff.
@duff
This is my one and only youtube made way back. May help explain.
http://www.youtube.com/watch?v=XXgL4Wf8zrQ&feature=channel_page
Also, I have pulsed many toroidal transformers with the same sound. Basically a some loose wires being vibrated making like a transducer action or more like a speaker coil.
Added.
When I had the sounds on my toroidal transformer, I took a flexible tube, put one end in my ear and used the other end as a sound prode to identify exactly from which part of the toroid it came from. In my case it was from the wire just at the center air core.
Quote from: duff on May 27, 2009, 06:55:33 PM
Yes, I am sure the magnet is singing.
It sings sitting on the top of the plastic spool and it also sings if I put it on a piece of paper and raise it above the spool (up to six inches). The beating freq ceases at 959Hz.
I don't have a piezo handy - will check radio shack...
The question is exactly which ambient fields is it interacting with and how do I prove it.
Here's a pic for better clarity.
-Duff
Edit: It also sings while holding it in my hand close to the top of the inductor though it is very faint.
Uh-huh.
Quote from: BEP on June 02, 2009, 07:28:27 AM
Amplifies?
Weren't there many folks here that determined a magnet had no real effect upon a coil?
Regardless, Nice work @duff.
@BEP,
The end effect is amplification though I don't really understand the mechanics. When the magnet is placed on the top of the spool it sings at one of the tones heard in the spool center cylinder and is louder. I don't know how the other tone becomes louder because it does not seem to be coming from the singing magnet.
@wattsup
Yes - your video demonstrates nicely the interaction of two signal in a wire with the magnetic field.
EM also demonstrated in a video the current interactions with the earth's magnetic field.
I believe same principle is at work in my inductor.
@all
Thanks for your input and comments
-Duff
Quote from: TinselKoala on June 02, 2009, 01:28:13 PM
Uh-huh.
A little note for those unfamiliar with the many types of hearing loss....
One, the one I am very familiar with, is weaker hearing at specific ranges. The range lost determines what the effect is but mine make me loose directional sense for sounds in the 800 to 2k range. (An ideal excuse when a female is screaming at me).
When I have a smoke alarm crying about a weak battery I just replace all the batteries because it would take me weeks to locate the one complainer.
I'm not surprised locating this sound was a problem. I would still like to know why it sounds around 960 when the coil is pulsed around 100k.
Do any one of you geniuses know how that could happen?
@duff
I've been trying to relate my noise maker to what you have found but doubt there is much relationship. Microphonics is not going to be an issue here because all winding turns have a 2 x conductor diameter spacing to the next turn and only one layer. Inductance isn't an issue since the resonance is determined by the core, not the windings.
BEP
Quote from: BEP on June 02, 2009, 05:46:53 PM
I would still like to know why it sounds around 960 when the coil is pulsed around 100k.
I'm also interested in the 960 signal.
Later this week I will take the inductor out of town away from the 60Hz as planned and see if it goes away.
My issue is I'm going to have to take my scope and an inverter. In the event there in no sound I'll need to verify it is still oscillating at the set frequency or perhaps verify the frequency the tone is heard.
Anyway I'm wondering if there is an issue with running a scope off a cheap inverter...
-Duff
Quote from: duff on June 03, 2009, 04:33:42 PM
I'm also interested in the 960 signal.
Later this week I will take the inductor out of town away from the 60Hz as planned and see if it goes away.
My issue is I'm going to have to take my scope and an inverter. In the event there in no sound I'll need to verify it is still oscillating at the set frequency or perhaps verify the frequency the tone is heard.
Anyway I'm wondering if there is an issue with running a scope off a cheap inverter...
-Duff
If you have a small isolation transformer you should put it between the scope and inverter. It'll soften the power wave shape a bit.
Either way the noise from the inverter can be just as bad as any mains noise in the house. If your inverter puts out square wave and has an effect it should be noticeable.
Do what you think is best but it would be easier to just kill all unused house circuits. Local E/M noise fields should have very limited affecting range, for the magnetic side, unless a load or circuit needs repair already.
Quote from: BEP on June 03, 2009, 05:03:10 PM
If you have a small isolation transformer you should put it between the scope and inverter. It'll soften the power wave shape a bit.
Either way the noise from the inverter can be just as bad as any mains noise in the house. If your inverter puts out square wave and has an effect it should be noticeable.
Do what you think is best but it would be easier to just kill all unused house circuits. Local E/M noise fields should have very limited affecting range, for the magnetic side, unless a load or circuit needs repair already.
Ok - I took your suggestion and turned off all the power to the house.
The beat vanished!
I double checked and did not turn off the circuit or disturb anything between test
So it seems that it is the 16th harmonic of the 60Hz grid.
As it turns out TinselKoala NAILED IT on the 5th post of this thread.
-Duff