efficiency :-)
An isolating belt is how they make a de Graaf generator, to produce high voltage. It would produce a very nasty leak to ground. a plastic rod with motor/dynamo attached would be better.
No joke, I have personally seen an aircraft go down because of it. New design, prototype was ready to go. Engine up front, prop in the rear, long shaft going through the fiber fuselage. I did some EMI fixing because that arrangement was causing static in the NAV/COM and this was a bear to debug because there was no ground to speak of. But I got it quiet. Then I wondered aloud whether the long shaft in a somewhat compliant fiber fuselage would not get out of whack at some rpm. "Nah, it was always fine in the run-ups and vibration tests" ... "What if there's g-load on the frame, like in a turn?" ... "Nah, it'll be fine".
Test pilot donned his leather helmet, fired her up. At first it all sounded ok but then somehow the rpms dropped during the takeoff roll and the engine sounded very labored. From then on the flight was doomed. Due to the proximity of the fence the pilot had no choice but to continue the take-off. It all ended in a potato field half a mile away and luckily the pilot was fine. The aircraft did not fare so well, suffered a serious prop strike which I guess meant a mandatory engine teardown. Later I inquired as to what went wrong. "Strong vibrations" ...
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
efficiency :-)
Just spray some charge on the belt and you might not need the generator.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
"John Larkin" "Phil Allison"
** Much more than that with a high efficiency LED lamp.Hardly matters when you are only generating 100mW.
.... Phil
The drive shaft on the F35 JSF transmits 32,000 horsepower to the forward lift fan. I understand there was some concern about stability. In fact, we sold some waveform generators to help out with the simulation. I think it's a tube, not a solid rod.
John
On a sunny day (Thu, 29 Apr 2010 20:21:12 -0400) it happened Spehro Pefhany wrote in :
efficiency :-)
Yes, wanted to mention vd Graaf, but was not sure if any charge would build.
On a sunny day (Fri, 30 Apr 2010 01:55:23 +0200) it happened Sjouke Burry wrote in :
efficiency :-)
Genius! Nice solution :-)
I seem to recall that his is called a Ward-Leonard arrangement, motor and generator on a common shaft. Many uses in electrical machinery / systems. Even as a frequency converter.
Old military electronics often used a "dynamotor" to make B+ voltages from low voltage DC. I think it was usually a shaft with a motor section and a generator section, spinning in a common field. All brushes of course.
The version with separate fields could be used as a power amplifier. That was an "amplidyne"
John
Shafts are pretty much always tubes but in my case it wasn't steel. Just from the gut feeling it didn't look kosher to me.
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Is the OP still around ?
I hope he now understands what he was asking for and will ask again for what he needs.
hamilton
Yeah, but then you are pretty darn close to a capacitor. Won't work with xx kilovolts between them :-)
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If you had really followed the thread you could have found out that surface mount is also desirable. Thus no mega-isolation.
Hmmm, surface mount or not, opto isolated power in not realistic.
I was wondering if the OP understands what he was asking, that there is no chance in hell that his request was feasible.
But the OP is an gmail poster, which mean he does not understand what he was asking.
hamilton
He said that the word "opto" was an oversight. He seems to want a conventional isolated dc/dc converter, and they are available in surface mount.
John
I did an opto dc isolator many years ago. The principle is still good, but the implementation my change:
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