Wireless power transfer via inductive coupling
Note: Schematics and information about the circuit is now available at 4hv.org: 4hv.org This is a small scale demonstration of wireless power transfer between two coupled parallel LC tuned circuits, each consisting of a copper conductor loop acting as an inductor and a capacitor. Both LC circuits are tuned to equal individual resonant frequencies. One of them is a part of a 1.5Mhz radio frequency oscillator powered by 12 volts DC, while another is loaded by a 24V 5W incandescent light bulb. Brought in proximity, copper loops share a small mutual inductance, essentially forming a transformer. In order to transmit significant amount of power through this transformer a very large amount of reactive power needs to circulate in it’s primary, requiring use of a thick copper tube for the conductor, and a bank of eight 6.8nF capacitors in parallel. Receiver coil’s leakage inductance is in turn canceled out by another capacitor, allowing for the maximum power transfer to the load. Experimenting with copper loop orientations, one can find positions of the receiver close to transmitter where no power is received, as total magnetic flux crossing through the receiver loop is zero. Hence this is a directional method of power transmission. Due to small size of the apparatus very little power is actually radiated in far field, with losses being mainly ohmic heating. Hence this method is also sometimes known as non-radiative or near-field power transmission.
Tags: copper conductor, leakage inductance, Wireless, transfer, mutual inductance
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awesome video, thanks ill have a go at making it!
lol, about a century later Tesla’s dream comes into the light.
@MarkoBakula Hey thanks Marko. I’ve been driving myself crazy trying to figure that out. I’m at work right now, not home where I can experiment to find out. But yeah it was racking my brain.
@genesisfan3,
I think you can easily come to an answer if you note that we are dealing with AC currents and the circuits are completely symmetric (no need to think farther than that – the receiver is still exactly the same circuit if you turn it 180 degrees around). So yes, the bulb will light the same. I didn’t exactly turn the receiver 180 degrees in the video, but I did something equivalent from 1:23 if you watch closely.
Why didn’t you flip the smaller loop around 180? I wanted to see if the light would still work if the poles were aligned in parallel. I’m trying to figure out if that would make a difference – In other words, would the law of series vs parallel still apply when only coupled magnetically? If you know the answer already please tell me.
Hello all,
I updated the 4hv thread with most frequently asked questions about the circuit – make sure to check it out before emailing me about the project!
thanks – Marko
Just a tranformer.
why err less, POWER, transmittion. its not that hard a concept to grasp surely??
100 years on, still in one out the other.
mutual inductance;)
Nice demonstration! gj
@SundayScientist then so be it :))
No it’s not :)
@SundayScientist Is Marco Rodin’s quote also a guess ?
I was referring to the earths magnetic field but unlimited energy gives us control of any magnetic field. If we can weaken the any field, we can also enhance it.
“He who controls magnetism, controls the universe” -Marco Rodin
when you say control magnetic field , are you saying we can control the magnetic fields on the hands -on neo-magnets or must it be just the earth’s magnetic field ?
Yes but a good one :D If we can ever get to the point where Teslas patents are released and we could actually use the energy wrom the atmosphere and transfer it anywhere on a scale where it would be free for all, we could no doubd use it to control the magnetic field if needed. My opinion is that we would not speed the weakening of the magnetic field by doing this. Someone prove me wrong.
is that a guess ?
false
type of the matching inductor used and its curent carrying capacity
hi!!!!what is the rating of capacitor and inductors at reciever`s end????
hiiiiiiiii!!! what is the rating of capacitor and inductors used at reciever`s end?????/
hey will u please tell me the radius of field that light can glow in this case????????
not very much I say about 10 feet
thats the thing with Inductive Charging
how much range between em can take ?
nice man you could be the new Nikola Tesla ! keep it up :)
Hello,
the bulb is rated 24V 5W, I had a bag of them in my garage and have no idea where they were intended to be used, perhaps truck turn lights?
I think you would be better to use 3 12V 2W bulbs in series instead. That should provide better impedance match.