Wireless Power? (The work of Nikola Tesla)


by Desmond108
Tags: nikola, power, tesla, wireless, work
Desmond108
Desmond108 is offline
#1
May30-11, 11:07 PM
P: 3
Nikola Tesla's work has always fascinated me.

I've always heard stories and claims of Telsa's ability to be able to wirelessly power light blubs and I always found the idea intriguing. I've been doing some research on his experiments, or rather I've been trying.

I'm finding it pretty hard to find any concrete or reliable sources on what Tesla actually managed to accomplish. I read somewhere it involved large metal plates that generated an alternating magnetic field, which makes sense, but again, I've found nothing in depth.

Basically, I suppose what I'm asking is if anyone can point me towards some more in-depth or reliable sources that discuss Tesla's experiments, specifically things regarding wireless power?

It's just something that really interests me, any help would be appreciated :)
Phys.Org News Partner Engineering news on Phys.org
Lifting the brakes on fuel efficiency
PsiKick's batteryless sensors poised for coming 'Internet of things'
Researcher launches successful tech start-up to help the blind
phinds
phinds is offline
#2
May31-11, 05:45 AM
PF Gold
phinds's Avatar
P: 5,682
Can't help you with a source, but good luck with that. I find the guy interesting. Have read some about him and saw a good documentary on TV. Seems he was quite the genius and his wireless power distribution worked but was utterly useless for all practical purposes involving actual distribution of any significant amount of power over any significant distance. I believe I saw a calculation somewhere that showed that you could in fact have a nationwide power grid in the US using his technology if you were willing to permanently bankrupt the entire world for its construction and maintenance (AND you were willing to give up the staggering amounts of real estate it would have taken).
MATLABdude
MATLABdude is offline
#3
May31-11, 03:36 PM
Sci Advisor
P: 1,724
If you haven't already seen it, there's a timeline (with references and links) over at the Wikipedia article on wireless power:
http://en.wikipedia.org/wiki/Wireles...wireless_power

What would've been his magnum opus, the Wardenclyffe Tower (primarily intended for worldwide radio broadcasting, but also as a longer-distance electrical transmission demonstration) ran out of money before construction was completed:
http://en.wikipedia.org/wiki/Wardenclyffe_Tower

0xDEADBEEF
0xDEADBEEF is offline
#4
Jun1-11, 06:24 PM
P: 824

Wireless Power? (The work of Nikola Tesla)


I think he basically used an alternating E-Field to power light bulbs. He stood on a stage inside a giant capacitor and was playing with fluorescent tubes. You basically just need a strong E-Field at some moderately high frequency to get the gas inside the tube into motion. A cheap way that produces very little light is just using the electrical field under transmission lines: http://pruned.blogspot.com/2008/02/f...ent-field.html

I think he also did some near field magnetic transmission. And had some large ideas that never really got realized. See. MATLABdude's link.
Meizirkki
Meizirkki is offline
#5
Jan31-12, 04:52 AM
P: 49
Sorry for necroposting, but I hope some of you will find this interesting.

I've replicated some experiments of Tesla. The wireless transmission is more like single wire transmission. The other end of the secondaries of the transmitter and receiver (tesla coils) have to be connected to each other with a wire or ground (earth) connection.

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.

Tesla's method of wireless transmission is very different from the conventional radio to which it's most often compared to. In a conventional radio the energy is radiated everywhere with only small portion of it reaching the receivers. In Tesla's radio, the energy is conserved.

I've also been playing around with joule thief circuits, which have much in common with Tesla coils. A two watt joule thief made from scrap components can "wirelessly" illuminate any fluorescent lamp. I must say it is very rewarding to experiment with electric fields. Unlike magnetic fields, they seem to work over long distances. I'm already working on constructing another set of Tesla coils for further testing of wireless transmission.
Alokin_Alset
Alokin_Alset is offline
#6
Feb14-12, 04:05 AM
P: 2
Hy Mezirkki.

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.
How did you get the resonance frequency? I could not find any formula for pancake coils, or bifilar pancake coils on the net & any physic book.

Why did you think that for higher frequencies the distance doesn't appear to be affected?
Fischer777
Fischer777 is offline
#7
Feb14-12, 10:23 AM
P: 67
Tesla coils are another method Telsa used to transmit wireless energy, although, like the radio, they tend not to be very efficient. Nonetheless, they are simple to construct if you have the time and are willing to invest in them. If your interested, here's a website I've found to be very helpful if you want to undergo your own projects: http://deepfriedneon.com/tesla_frame0.html
Meizirkki
Meizirkki is offline
#8
Feb14-12, 10:37 AM
P: 49
Quote Quote by Alokin_Alset View Post
Hy Mezirkki.

How did you get the resonance frequency? I could not find any formula for pancake coils, or bifilar pancake coils on the net & any physic book.

Why did you think that for higher frequencies the distance doesn't appear to be affected?
I didn't calculate the frequency. I winded two coils as identical as possible, except for the direction of winding, and measured the frequencies of standard induction and "Tesla transmission" with my schools equipment.

At the resonant frequency of individual coil I could induce electricity from one to another with distance of <2cm. The induction would fail whenever the coils were taken more than ~2cm away from each other.

When operated at the higher frequency I could leave transmitter into my room, and walk around the house holding the receiver, it's LED's shining brightly. I set up the coils for demonstration at my school's open house day and we also measure the efficiency of the transmission. 10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW. This is 95% efficiency with a distance of about 6 meters. I expect it to be much closer to 100% with better coils and proper primary circuit.

In the above test, the transmitter was powered from a function generator and all voltages were RMS measure with an oscilloscope.

I'm planning to test my new coils at distances of over 100 kilometers, but it's going to take a while because building a powerful primary circuit for the transmitter is rather difficult :/
Meizirkki
Meizirkki is offline
#9
Feb14-12, 11:50 AM
P: 49
Quote Quote by Fischer777 View Post
Tesla coils are another method Telsa used to transmit wireless energy, although, like the radio, they tend not to be very efficient.
[citation needed] ?

Tesla coils is exactly the way to go for efficiency.
jim hardy
jim hardy is offline
#10
Feb14-12, 06:58 PM
Sci Advisor
jim hardy's Avatar
P: 3,138
10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW.
were both resistors in both circuits at times of both measurements?

and i assume you meant to type: 'primary showed a voltage drop of ~380 mV.' ?
Fischer777
Fischer777 is offline
#11
Feb14-12, 08:39 PM
P: 67
I am curious about these pancake coils. Where can I get information regarding them (how they work and all that stuff)?

My miniature pancake coils have resonant frequency of about 9 MHz each. With this frequency, close range transmission via magnetic induction is possible. With longer distances, the frequency of transmission must be increased to pi/2 times the resonant frequency of individual coil. With my coils this is roughly 14MHz, but will vary depending on the ground connection. With this higher frequency, the distance between the two coils doesn't appear to have any effect on the transmission.
I am not sure I understand this. How can a resonant circuit operate outside it's resonance frequency?

When operated at the higher frequency I could leave transmitter into my room, and walk around the house holding the receiver, it's LED's shining brightly. I set up the coils for demonstration at my school's open house day and we also measure the efficiency of the transmission. 10 ohm resistor in series with the primary coil of the transmitter had a voltage drop of ~400mV and another 10 ohm resistor in series with the receiver's primary showed a voltage drop of ~380mW. This is 95% efficiency with a distance of about 6 meters. I expect it to be much closer to 100% with better coils and proper primary circuit.
How is the energy being transferred from the emitter to the receiver? Is it magnetically or electrically? Do the coils have to be aimed at each other for the transfer efficiency to peak?

Forgive me for asking what are probably really silly questions. I am a freshmen electrical engineering major with absolutely no formal training in electrodynamics whatsoever.
Meizirkki
Meizirkki is offline
#12
Feb15-12, 06:26 AM
P: 49
Quote Quote by jim hardy View Post
were both resistors in both circuits at times of both measurements?

and i assume you meant to type: 'primary showed a voltage drop of ~380 mV.' ?
yes to both.
Meizirkki
Meizirkki is offline
#13
Feb15-12, 07:28 AM
P: 49
Quote Quote by Fischer777 View Post
I am curious about these pancake coils. Where can I get information regarding them (how they work and all that stuff)?

I am not sure I understand this. How can a resonant circuit operate outside it's resonance frequency?
There appears to be two resonant frequencies. The lower is for magnetic induction and the higher for electric field induction. Tesla stated that his wave travels pi/2*c (faster than light). The resonant frequency for Tesla transmission is also pi/2 times the frequency of magnetic induction.

Quote Quote by Fischer777 View Post
How is the energy being transferred from the emitter to the receiver? Is it magnetically or electrically? Do the coils have to be aimed at each other for the transfer efficiency to peak?
According to Tesla himself, his radio was not magnetic and my experiments lead to the same conclusion. The transmission is achieved with the use of resonating electric fields. This way, the receiving coils acts like a capacitor in series with the capacitance of the transmitter. Or that's what I think. I've been trying to figure this out for many months now and of all the proposed explanations this makes the most sense. Coils do not need to be pointed at each other, the position of the coils does not affect the transmission.

And please don't apologize for asking those questions. It's so hard to find reliable information of the Tesla transmission that after reading some books and browsing through hundreds of shady websites I decided that the only way to understand it is to do it myself. I encourage you to do some experiments too. :)
Fischer777
Fischer777 is offline
#14
Feb15-12, 02:59 PM
P: 67
Is a Tesla pancake coil essentially the same as a Tesla coil with the windings in a flat spiral instead of in a helix, i.e. there's a primary coil of a just a few turns of thicker wire, and a secondary that's several hundred to several thousand turns of small wire (with one end grounded and the other attached to a circular or toroidal capacitor)?
Meizirkki
Meizirkki is offline
#15
Feb16-12, 04:54 AM
P: 49
Quote Quote by Fischer777 View Post
Is a Tesla pancake coil essentially the same as a Tesla coil with the windings in a flat spiral instead of in a helix, i.e. there's a primary coil of a just a few turns of thicker wire, and a secondary that's several hundred to several thousand turns of small wire (with one end grounded and the other attached to a circular or toroidal capacitor)?
Yup.

EDIT: [According to Tesla's patents.]
jim hardy
jim hardy is offline
#16
Feb16-12, 08:46 AM
Sci Advisor
jim hardy's Avatar
P: 3,138
so in your experiments are primary and secondary connected by this "ground" ?
If so, is it a wire between the coils or rods driven into earth near each coil?
Meizirkki
Meizirkki is offline
#17
Feb16-12, 09:35 AM
P: 49
Quote Quote by jim hardy View Post
so in your experiments are primary and secondary connected by this "ground" ?
If so, is it a wire between the coils or rods driven into earth near each coil?
The primary and secondary coils are not connected to each other in either of my coils.

Did you mean to ask whether the secondaries of the pancake coils were connected? They are connected with a wire. Tesla himself used Earth in the place of this wire, but I haven't been able to test that myself since it would need a very good RF ground, and I don't have an Earth grounding of any kind. :/ Besides, using Earth ground would be rather difficult with coils this small. The pancakes are only about 15cm in diameter.
sophiecentaur
sophiecentaur is offline
#18
Feb16-12, 01:07 PM
Sci Advisor
PF Gold
sophiecentaur's Avatar
P: 11,352
That danged Tesla rears his head again. I wonder what the FCC would have had to say about his experiments if he'd tried to carry them out today.

Amazing that all those high powered US tech. companies never took on board his 'fantastic' schemes. They certainly missed a trick there.

Reading what people have to say about our Nicola rather puts me in mind of the old Soviet history books that their Schools taught from. Read them and you'll learn that Soviets invented pretty well everything technological since the Revolution.


Register to reply

Related Discussions
Nikola Tesla's Death ray General Physics 9
Nikola Tesla General Physics 18
Nikola Tesla Introductory Physics Homework 8
Nikola Tesla General Discussion 4