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help needed for MEG tuning   Message List  
Reply | Forward Message #1298 of 1374 |
Hello guys,

I'm new to this group, but it seems that some of you have some
experience with the MEG, so that's why I'm posting here the details of
my experimentation up to now. I'm also hoping anyone could have some
hints and tips to make my MEG work properly.

Fist, I've been studying the MEG for more than a year now and I've
made my first prototype 4 months ago. I have built the MEG from the
patent. I used an AMCC630 Metglas core with a rare earth neodium
magnet, (N42 grade) the exact same size as we can find in the patent.
Also, I'm testing with two combinaison of load.
1. 3x 33k (1Watt) resistor in serie total 100Kohm each side
2. 3x 33k (like 1) but with an added 460V MOV (BC1400-ND) in serie

As far a I have tested, the Mov is not helping at all. I do consider
the power dissipated in the Mov as lost power.

Also, my inputs are 2 50% square waves generated by a D-latch. These
2 signals then go through 2 sets of push-pull fet combination (n and p
fets). And like JL Naudin's design, I used nFet to "drain" the
current. My fets are IRF520

My best resuslts were COP = 0.74 to COP 0.78.
Theses results were calculated with an input of 32.6 Volt (DC) *
0.1408 Amps = 4.59 Watts for an outpout of average 141 Vrms on linear
resistor => 3.6147 Watts, for a cop of 0.7875.
I consider theses results as average, but the mesurement are precise.
I used a digital Fluke oscilloscope to calculate the RMS voltage on
the output and a good multimeter to calculate the input amps from the
power sources.

The patent seems to say that I will have to put more volts in to get
better results, but I don't see a big difference between 5 volts in or
35 volts in (with a COP perspective)

Also, I played a lot with the frequencies and it seems that my MEG is
optimum with input frequencies of about 30-45kHz. If I go outside of
these frenquencies, I loose a lot in efficiency.

As I'm looking for some insight, I wonder if anyone knows how
JL-Naudin got his input wave exactly like Bearden. What I mean is
that my input and output are not as "clean" as his. I have a lot of
high frequency phenomenon in my input and my output wave his slightly
distorded. I'm beggening to think this is where my problem his, but
I'm not sure how to solve it.

Anyway if anyone has clues, I would apreciate them

Thanks
Ccool








Thu Apr 20, 2006 2:15 am

ccool_j
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Forward
Message #1298 of 1374 |
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Hello guys, I'm new to this group, but it seems that some of you have some experience with the MEG, so that's why I'm posting here the details of my...
ccool_j
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Apr 20, 2006
4:49 am

... Have you tried lower pulse width with a deadtime in betwwen? Say something like 2 x 40% with 10% OFF. Mark Jordan...
Mark Jordan
enkitec
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Apr 20, 2006
4:51 pm

No. Never tried....
Mark Jordan
enkitec
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Apr 21, 2006
3:46 pm

I have'nt tried either... As far as I know about the meg, what is important is to get fast switching. Faster you go, the better it should be (as said in the ...
ccool_j
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Apr 26, 2006
12:19 pm

No, because my meg was started as a project with some high school kids last year... we got it built and just started testing and the school year ended. By then...
Brent Selleck
selleck999
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Apr 22, 2006
4:37 am

... the real ... Bearden told ... but the ... beyond the ... secondaries was ... the key ... the core ... errant ... it's so ... Thank you for your insight on...
ccool_j
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Apr 26, 2006
12:20 pm

... As the core goes into saturation, the field will be less contained in it, so if good things happen when saturation occurs, it refutes the idea that high...
ey930
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May 5, 2006
1:54 pm

Hi, it's me again, I have some updates and some graphics. Theses graphics show one of my biggest challenge into understanding and making work the MEG. This...
ccool_j
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Apr 26, 2006
12:19 pm

In looking at your output waveforms, it appears that your MEG is still a "Biased transformer". Note the skewed output waveform. Try changing the input...
Norm Fletcher
fletchmo47
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Jun 4, 2006
3:15 pm

You point out one the more interesting aspects to all of this... the ability to measure what's really going on... I sell robotic lawn mowers that use a ...
Brent Selleck
selleck999
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Apr 26, 2006
7:53 pm

On Sun, 04 Jun 2006 05:56:48 -0000 "Norm Fletcher" <fletchmo47@...> wrote ... I have 2 comments, for which I hope to see a reply: Since the core is...
Wayne Robey
ey930
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Jun 8, 2006
2:30 pm

... secondary on it's leg. You can see this clearly in old TV fly-back transformers. Could this secondary resonance be what you are tuning for? OK Let me see...
Norm Fletcher
fletchmo47
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Jul 19, 2006
7:20 pm

Very well said.... and I await your results eagerly... ... From: "Norm Fletcher" <fletchmo47@...> To: <MEG_builders@yahoogroups.com> Sent: Tuesday,...
Brent Selleck
selleck999
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Jul 21, 2006
3:15 pm
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