Wireless Power Transfer

reply to post by OrionsWitness


Tesla did it. I cant see why we couldnt.

A little FYI for you...

Read down a little and you will see the reason for the 377 (not 347 actually) volts in the puddle.

Residential electrical power can range from 110 VAC to 130 VAC. It depends on where you live and what taps the power company has their transformers set to. The higher voltage used for electric stoves, dryers and such will be twice your primary low voltage. In other words, if you have 115 VAC at you wall outlets you will have 230 VAC for your appliances and if you have 130 VAC at the outlets your appliance voltage will be 260 VAC. The most common voltage supplied is 120 VAC and this is what your small appliances are designed for. But the power companies are allowed to vary the voltage by 10% under most local electrical codes.

Industrial three phase power supplies are different from your home supply. There are very few true three phase systems at 220 VAC. (I am going to use the median but the 10% variance still applies) What the power companies do to save money is use a two transformer system that uses one transformer identical to the home supply system. That gives you two legs of the three phases at 180 degrees apart and they tap one other line of the three phase transmission lines and use a second transformer to provide the third leg. So what you end up with is three phases at a rotational relationship of 0 Deg, 180 Deg and the third at 240 deg. A true three transformer system would give a relationship of 0, 120, 240 Deg. Another anomaly of the two transformer three phase system is that you have a "high leg". The two legs that are part of the single transformer that supplies 240 VAC will be 120 VAC to neutral. But in order to keep the phase to phase voltage correct the second transformer for the third leg will be set at 208 VAC. Many a weekend warrior electrician has burned out electrical and electronic gear by tapping into the high leg for their 120 VAC supply. If anyone is having trouble with this say so and I will give you a link to a site that illustrates it.

Industrial 440 VAC systems use all three transmission lines and three transformers. This give a true three phase supply. And here is where the 377 VAC comes in. That is the voltage from any of the three phases to neutral. And a great deal of your industrial and municipal lighting systems operate at this voltage. In a true three phase system there is no "high leg" like there is in the industrial 220 VAC system.


NOTE: If you are having trouble with appliances and light bulbs burning out too frequently check your outlet voltage. If you are running at 130 VAC sometimes you can have the power company change the taps on the transformer that supplies your household power to a lower voltage.

Originally posted by SonsOfTheMeek

Excuse me, but Tesla was a pioneer in the field of resonant inductive coupling and a Tesla Coil, while capable of electrical discharges, is actually, at its heart, a resonant transformer. Don't just write off his contributions like that.

In this case, Tesla's work has no bearing. It's not a Tesla coil. It's all h-field stuff. It's sort of the total opposite of Tesla's work, which was primarily e-field.

Originally posted by Arbitrageur
I'm not that concerned about low power radio signals in the air, but transmitting higher power levels concerns me more. One thing we discovered with technicians in the military working close to microwave transmitters is that exposing them to higher power levels increased their risk of developing cataracts.

Soljacic's designs go out of the way to avoid radiating radio signals. Putting a lot of near field out that won't propagate at all is a trick, and it's one of the keystones of the system.

The question is, is a veritable #-heap of near-field radiation ok? People carp about RFID causing cancer (which it doesn't) but this thing's essentially God's Own Interrogator - it's the same technique (and frequency, usually) used to pump a near field RFID part. Only wrote large.

Originally posted by Arbitrageur
However that said, I suspect if you plug in one of these wireless battery pack rechargers and put it in some un-used corner of your house, the risk to humans is pretty low. If however you put it on your desk close to where you work, I'm not so sure.

One of the original proposals for WiTricity was that we'd all be building them into the floors or ceilings of our homes, and nothing in the house would have a cord. The whole thing would be lit up with kiloWatts of near-field radiation.

Now, one thing I DID look at the first time I read Soljacic's first paper on this was to see if anyone at MIT had patented it for powering internal medical devices, like VADs. That would be a NICE use of it - have some internal battery power, when you're home you are always powered by the house's field, and you don't have to wag around a life vest full of batteries. But they'd already cited it. Alas.

Was reading through the replies to this thread, and to be honest , a lot of the replies don't get the implications.
Tesla, God remember the experiments in High school?
There is this thing , that has haunted my thinking since I became an Electrical apprentice a couple of decades ago.
What if Power ie P= E times I is an illusion?...a false premise.
Based on the resistance factor?
That hardly exists through air.
I think this is what they will achieve.

reply to post by OrionsWitness

That hardly exists through air.

You think air is a good conductor of electricity?

It should also be pointed out that Tesla's wireless transmission idea did not involve transmission through the air, but through the ground.

Originally posted by OrionsWitness
What if Power ie P= E times I is an illusion?...a false premise.
Based on the resistance factor?
That hardly exists through air.

This isn't conducting current through air. Neither e nor h field coupling conducts like a wire.

reply to post by Phage


Of course it is, but that was the point of the post, we are by logic told air is not a good conductor, and Iam using the term air loosely.
Because you can not get electrocuted until you touch , doesn't explain it all.
JUst bought the wife a duelling helicopter double pack RC package for xmas, just sat there for ages touching the remote control and seeindg the helicopter rise up in the air.
How unbelievably odd is that?
The helicopters are 1/40th scale.
The power needed is six aa batteries per remote, plus the battery receiver in the helicopter.
How unbelieveable is that if we stop and think.
In the future air will be full of manipulated current algorithms.

reply to post by OrionsWitness

How unbelievably odd is that?

Not very. But it is fun. What's the transmitter put out? about 30mW? Not really any transmission of power going on there, just electromagnetic signaling.

In the future air will be full of manipulated current algorithms.

Radio waves are not electrical currents. And the air is full of them.

reply to post by Phage

Ok Iam posting on instinct have had a few beers and Iam postulating on flimsy theory, but these signals allow a little model helicopter to rise in the air fly around ect.
The big picture is sometimes , clouded over by established theory.
Alexander Bell patented the Photophone , but it took a long time for it to become a feasible method of transferring power... ok signals.
I know you are probably 100 times more knowledgeable than I , but i still think , somehow the whole world will operate wirelessly.

anyone ever put 2 tesla coils on the direct dirt and try to light the second from xmitted power from the first?

just an idea..

if that works in mini, can see how pyramid coils could arc power thru the core itself to any country.with a receiving pyramid

Originally posted by mellisamouse

347 is a Voltage that KILLS! !!!!!

Correction, 347 volts is hardly anything in the least. Consider this:

You can legally buy a NON-LEATHAL 5 MILLION volt stun-gun. It isn't the voltage that harms people, it's the amperage. 347 volts wouldn't be enough to decapitate anyone, let alone bring any significant harm to someone, or in this case, something.

I was going to give the math proving that 340V is bad stuff, however, I will just say, a stun gun does not have enough current for long enough to kill some one with a good heart. Voltage hurts, current kills and potential current does nothing!

It all has to do with skin resistance at the time, the amount of current that can be supplied(stun guns have lowish current), how long you are exposed for and how healthy the heart is.

Dare you to stick your tongue on the 120V wall socket, its less the 340V so "somehow" its ok lol. 9 volt batteries are bad enough, never lick anything above 12V as the resistance issue will prove its self.