If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #2860
Joined: Sun May 16 2010, 06:59AM
Location:
Posts: 5
Hi all, I'm working on Witricity and there is a problem. When I try to put a second multi-turn copper ring near the single turn source coil, system performance becomes even worse. I have no idea what to do. Could someone can help with me ? I have a photo that one multi-turn copper ring is working as follow
Registered Member #531
Joined: Sat Feb 17 2007, 10:51AM
Location: Burlington, Vermont
Posts: 125
zxshow wrote ...
Hi all, I'm working on Witricity and there is a problem. When I try to put a second multi-turn copper ring near the single turn source coil, system performance becomes even worse. I have no idea what to do. Could someone can help with me ? I have a photo that one multi-turn copper ring is working as follow
It's not entirely clear to me what your setup / question is but... Bear in mind that the technique is nothing more than link coupled high Q resonators. Ignore the obtuse approach that the MIT group took to explaining the operation, it will simply confuse things.
The MIT group had two resonators - one resonator was loosely coupled to the single turn 833A power oscillator, the other resonator was loosely coupled, also via a single turn I believe, to the lamp (load). The resonators were, in turn link coupled to one another. Think of it as dual Tesla coils in which the secondaries are magnetically coupled to each other.
Registered Member #2860
Joined: Sun May 16 2010, 06:59AM
Location:
Posts: 5
scott fusare wrote ...
zxshow wrote ...
Hi all, I'm working on Witricity and there is a problem. When I try to put a second multi-turn copper ring near the single turn source coil, system performance becomes even worse. I have no idea what to do. Could someone can help with me ? I have a photo that one multi-turn copper ring is working as follow
It's not entirely clear to me what your setup / question is but... Bear in mind that the technique is nothing more than link coupled high Q resonators. Ignore the obtuse approach that the MIT group took to explaining the operation, it will simply confuse things.
The MIT group had two resonators - one resonator was loosely coupled to the single turn 833A power oscillator, the other resonator was loosely coupled, also via a single turn I believe, to the lamp (load). The resonators were, in turn link coupled to one another. Think of it as dual Tesla coils in which the secondaries are magnetically coupled to each other.
You appear to have a single resonator?
Regards
Scott N2BJW
Really thank you. But I still don't know how to do. Could you discribe in details or send me some information to study ?
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
zxshow wrote ...
Grenadier wrote ...
So if I'm understanding you correctly, when you add another coil the lamps get dimmer? That just sounds like loading to me...
Yes that's right! Mit guys use two multi-turn ring. According to mu results, only one is needed.
Hi zxshow,
In short, just putting random coils of wire near your transmitter and receiver side is ofcourse pretty unlikely to do any good at all. The coils are resonators that have to be tuned just like tesla coils. The reason you seem not to need another helical resonator near the transmitter is that you already have one - it's the output tank circuit of whatever tube oscillator you're using - and it's capable of carrying enough reactive power to make your oscillator alone a formidable wireless power-transmitter. You could change the parameters of it's tank circuit for impedance matching (more turns, less capacitance) to get the Q and power throughput higher, but it's generally considered easier to magnetically couple another resonator to the first one to perform this job.
You need to consider though that putting those two resonators in close magnetic coupling will make whole oscillate at a completely different frequency, and this system will not anymore be in tune with your receiver! Hence you'll need to re-tune your receiving resonator by adding more turns or compressing it up so it's f0 goes lower. I'd also advise to try using a few-turn coil with a tap (aligator clip or etc.) for your light bulb and play with the tap a bit until you find the bright spot.
Registered Member #2860
Joined: Sun May 16 2010, 06:59AM
Location:
Posts: 5
Marko wrote ...
zxshow wrote ...
Grenadier wrote ...
So if I'm understanding you correctly, when you add another coil the lamps get dimmer? That just sounds like loading to me...
Yes that's right! Mit guys use two multi-turn ring. According to mu results, only one is needed.
Hi zxshow,
In short, just putting random coils of wire near your transmitter and receiver side is ofcourse pretty unlikely to do any good at all. The coils are resonators that have to be tuned just like tesla coils. The reason you seem not to need another helical resonator near the transmitter is that you already have one - it's the output tank circuit of whatever tube oscillator you're using - and it's capable of carrying enough reactive power to make your oscillator alone a formidable wireless power-transmitter. You could change the parameters of it's tank circuit for impedance matching (more turns, less capacitance) to get the Q and power throughput higher, but it's generally considered easier to magnetically couple another resonator to the first one to perform this job.
You need to consider though that putting those two resonators in close magnetic coupling will make whole oscillate at a completely different frequency, and this system will not anymore be in tune with your receiver! Hence you'll need to re-tune your receiving resonator by adding more turns or compressing it up so it's f0 goes lower. I'd also advise to try using a few-turn coil with a tap (aligator clip or etc.) for your light bulb and play with the tap a bit until you find the bright spot.
Marko
Thanks Marko. Your suggestions really give me some new ideas ! I didn't make any Tesla coils so I don't know how to tune it. "You could change the parameters of it's tank circuit for impedance matching (more turns, less capacitance) to get the Q and power throughput higher, but it's generally considered easier to magnetically couple another resonator to the first one to perform this job. " I don't understand wht's this mean?
I'm still not clear the role of the two multi-turn coil. The receiving one can carry more reactive power than single turn. However, the other one near the source seems to be redundant.
Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062
i did recall reading somewhere that one major problem with WiTricity is proximity effects on the transmitter. AFAIK there is a workaround, but it would require tuning the RX tank as well which doubles the complexity.
Interestingly, one possible option is waveshaping, by using lots of small highly directional coils and slightly altering the relative phasing like a PA radar system or ultrasound, the field could follow the RX around a room without actually moving the coil (!) i think a similar system is used on some WiFi access points being sold now.
-A "Bother!" said Pooh, as the Phoenix failed to enter Warp...
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.