Introduction to Resonance

[Charlie_V]

I thought we'd need another transformer there in the secondary circuit to actually hook up the load. Wasn't it all going through the ground in Tesla's case so you would tap the ground to get the good stuff and would not need another transformer ? I guess the other component were Longitudinal Waves which were instantaneous (propagating at c^2 iirc from Eric Dollard's lecture).

I don't know about c^2 and instantaneous, I'm not that far yet.  But if you take another transformer and get it oscillating from the ground currents (which come from the secondary of the main Tesla coil - we'll call it the transmitting Tesla coil) and hook a load to this transformer, it damps the system still because you start draining the energy in the two circuits that normally would slosh back and forth.  So the power from the source that input the energy into the transmitting Tesla coil, will again have to add more energy to keep the oscillations going.  The ground oscillations allow us to use 1 wire (the ground) instead of 2 (a hot and a ground).  Basically we make the 1 wire serve as both a hot and a ground simultaneously. 

You can collect energy though from natural sources - and man made, like my coil does with 60Hz.  For example, the earth mechanically vibrates at 7.5Hertz.  Because the ground and ionosphere act as a big capacitor, when the earth vibrates it creates a weak AC wave which is normally measured to be small.  But maybe a Tesla coil tuned to this resonance could pick that up and power loads from it - who knows!

Sorry for such a long post last time.  I kinda got carried away haha - I like talking about this stuff. 

[amigo]

You can collect energy though from natural sources - and man made, like my coil does with 60Hz.  For example, the earth mechanically vibrates at 7.5Hertz.  Because the ground and ionosphere act as a big capacitor, when the earth vibrates it creates a weak AC wave which is normally measured to be small.  But maybe a Tesla coil tuned to this resonance could pick that up and power loads from it - who knows!

The more I look at Tesla's patents more I believe that his intention was not to use the circuits with our conventional devices. If anything, we need to create the same loads as he did in order to tap into it and get useful work out. And you know that he had built lots of custom light bulbs, motors and such items that ran on his circuits no problem.

I think we are just trying to push a square peg through a round hole and it won't work, but we still keep trying never the less. I keep saying about it all the time but it falls on def ears. Moment there's a possibility about some alternative device producing energy, people try to short circuit it so it runs on conventional loads. It's like trying to bring the mountain to yourself, when it's much much easier to just take the trip to the mountain and be blessed with beautiful sights, clean air, rocks and trees and flowing streams of water.

Sorry for such a long post last time.  I kinda got carried away haha - I like talking about this stuff.

Hey, you and me both, but that's great because it gets the ideas going, information is exchanged, and we are both richer at the end.

[Charlie_V]

Yea, I think you are right, he did make custom loads.  In his day these loads still had a chance since electricity was new.  There was a possibility of everyone going down his route but unfortunately they didn't. 

I'm interested in finding ways to power the devices we have today.  It would be hard to come up with different types and actually market them, you'd almost have to start over - 200 years invested on the types of loads we have now.  They built a mountain of trash, it would be really difficult to try to topple it.  Instead I want to recycle that trash by finding a clever way of using the loads we have, I know its possible because the universe itself MUST function with both energy consuming and regenerating - this must be balanced.  Whatever energy is going downhill in the universe there is a mechanism that is bringing it back up the hill, no one has figured out what that is - but I know it is there, otherwise we would not exist. 

I have some ideas I'm trying but right now its slow going.  Its only a matter of time before someone figures it out.  I think armagdn03 is right when he says there are ways to use the same energy over and over again.  The trick is going to be a way to link the regenerative part to the resistive part without damping.  There are a million ways to skin a cat, we just need to find the cat first hahaha! 

I'm off to bed, good night.

[amigo]

You have a capacitor of 0.2 micro farads and a resistor of 20,000 ohms.  Lets assume we use a 10,000V source that can supply 1amps.  We have a spark gap so that when the capacitor reaches 10kV the spark gap discharges into a 4 micro henry inductor of very low resistance (i.e. large wires).  So, the capacitor and inductor make a tank circuit when the spark gap discharges.

The time it requires to charge the capacitor up to 10,000V is roughly 0.004 seconds.  Since the capacitor is discharged so rapidly when the gap fires, we can neglect the fall time of the capacitor.  This means that we can fire the gap at about 250 times in one second (250Hz).  How much energy is in the capacitor when it dumps into the inductor? 
E=0.5*C*V^2
So the there are 10 Joules in the capacitor when it fires.  We are inputting P=10/0.004, about 2500 Watts of power into the tank circuit.  HOWEVER! What is the power in the tank circuit - it is NOT 2500 Watts!  The resonant circuit oscillates at 177,940 Hz [ f = 1/(2*PI*sqrt(LC)) ].  The time constant of the tank circuit is 5.6 micro seconds!!!  The energy in the capacitor is still 10 Joules, so the power of the oscillation is 10/5.6micro which is equal to about 1.779 Mega Watts (1,779,406 Watts). 

Do we have over unity?  No we don't, that is because that 1.8 mega watts of power is all reactive.  This means that the 10 Joules of energy is only tossed back and forth between the capacitor and inductor 177,940 times in one second but the amount of energy in the system does not change (just 10 Watts and decreasing due to resistance).

Could you please elaborate on the numbers here since I am kinda confused. I see where you got the 0.004 sec for charging (ref: http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/capchg.html#c2) but I am puzzled about your power computation and the pure reactive power. This is where I'm looking for reference http://www.sayedsaad.com/fundmental/66_OHMS%20LAW%20FOR%20AC%20.htm which is basically NEETS in colour.

According to that page, reactive power is based on reactive current and total reactance, but we are in resonance so wouldn't that make X=0 |XL-XC| making the whole circuit only resistive with true power of 5KW, or did I get all this wrong?

[Charlie_V]

The time it takes a capacitor to charge up is R*C (resistance times capacitance).  The energy the capacitor stores is E = 0.5*C*V^2 (one half times the capacitance times the voltage squared).  With a voltage of 10,000 Volts, and a capacitance of 0.2microfarads, the energy in the capacitor is 10Joules.  Power is Joules divided by seconds.  Since the capacitor discharges into an inductor of neglectable resistance, the time constant for discharging is basically zero and the only wait time we have is the charging time constant (which was 0.004 seconds).  Therefore, with our spark gap set to fire when the capacitor reaches 10kV, the power we are inputting to the capacitor (which dumps into the inductor) is 10/0.004 or 2500Watts.

When the spark gap fires, it shorts the power supply and essentially disconnects the capacitor, leaving the capacitor and inductor as a separate circuit for a certain amount of time until the spark in the gap goes out.  In this instant of time, the capacitor and inductor form a tank circuit with no load.  The capacitor (disconnected by the closed spark gap from the power supply) dumps its energy into the inductor.  The inductor, in-turn, takes that energy and dumps it back into the capacitor.  The energy continues to slosh back and forth between the two components at a frequency of f = 1/(2*PI*sqrt(LC)) = 177,940 Hz.  If you read about tank circuit resonance, you will find that the energy sloshing in the tank circuit is purely reactive.  In one instant, the capacitor is charged and no current flows in the inductor.  In the next instant all the current is flowing and there is no voltage in the capacitor.  Basically, the current and voltage in an oscillating tank circuit are 90 degrees out of phase, this is purely reactive power.  The resistance of the tank circuit damps it, otherwise it would ring like that forever - so I suppose in a real situation there is a small amount real power being consumed due to wire resistance, if we used super conductors it will oscillate indefinitely.

In fact, by putting a load on the tank circuit, it won't oscillate at all.  The capacitor will dump that 2500 Watts into the load once, if it is a light bulb it will light up one time.  However, if you start charging and discharging the capacitor at  177,940Hz you will be putting the most energy into the load that can be placed.  If you go higher or lower than 177,940Hz, the light bulb will not be as bright.  In the case of a loaded tank circuit, the tank turns into a filter and it guarantees that only signals input at its resonant frequency will fully reach the load.

According to that page, reactive power is based on reactive current and total reactance, but we are in resonance so wouldn't that make X=0 |XL-XC| making the whole circuit only resistive with true power of 5KW, or did I get all this wrong?

That's because that website is talking about apples and not oranges.  It is explaining how a circuit acts if you are trying to input energy to a load that has a "filter" within it.  Yes, if you have a load with some reactance and you want to give it the most power, you want your input frequency (your power supply frequency) to match the resonant frequency of that "filter".  If you take away the load from the filter, and are left with just the filter, at resonance the energy will just slosh back and forth and you'll only get reactive power.  Basically the energy you send to the filter will bounce back if there is no load to absorb the energy.  You will rarely find a website that talks about energy bounce back simplistically because it is something they try to avoid (and is rarely thought about and understood - I think).  Radio websites give the best details into this matter. 
http://www.ycars.org/EFRA/Module%20C/TLSWR.htm
Read the linked page of this website (but just this first page that I have linked - making sure to watch the "click here" videos - because other sections of this guys website are crappy).  This one page gives a really good simple explanation of how energy can bounce back in an electrical system.

Hope that helps!