Confirming the Delayed Lenz Effect

[Farmhand]

Farmhand:

I agree with you about Thane's logic.

MileHigh I do see your point about the stored energy, But rather than being stored and resonant as in when there is no load isn't it transferred more directly with no Q ? Kinda like by transformer action.

I am not sure what transfer you are talking about.  I assume that Tesla tried to optimize the Q factor for his setups.  If you can explain more I will try to respond.

MileHigh

Slight misunderstanding, I didn't clarify, I was referring to just a regular high impedance coil used by Thane ect. Or even to the single winding coil I used with a capacitor across it to lower it's frequency enough to hit the harmonics. I wasn't referring to Tesla's coil there. My bad.

In this short clip, we can see the input current reduce from almost 2.5 amps from the 12 volt battery to about 2 amps from the 12 volt battery while accelerating under short circuit, the reason being the load or draw on the battery is reduced, the reason for that is the motor is seeing less load, and the reason for that is the reduction of the induced drag on the generator rotor. How the load on the rotor is reduced is irrelevant because the input power dropped only slightly when loaded by the bulb which was only 3 watts rated I think. But the input was around 30 Watts unloaded and dropped to about 24 Watts when shorted. Either figure is seriously inefficient no matter how it is looked at.

http://www.youtube.com/watch?v=iFWin-crxQY

The same thing happens when a transformer is driven to resonance (max voltage) the input to do that at idle is increased as compared to not, then when the load is added the parameters are changed and the setup is put "out of tune" so the input drops and unloads the supply, the output is dismal of course, as is predicted by the MIT lecture I linked.

At least part of the reason for the behavior/effect is already predicted by conventional knowledge.

Cheers

[MileHigh]

Farmhand:

I can suggest a theory that may explain what happens in your clip.  The first step is the fact that a shorted pick-up coil is likely to be a very low load on the rotor because there is no power being transferred into the "load."  The basic idea is that open-circuit is no load, a short is no load, and somewhere in between those two extremes is the matching load for maximum power transfer and 50% efficiency.

In addition, I believe the shorted coil should remove the most or all of the cogging.  A simple spin-down test comparison with no load resistor and a "zero ohm" load resistor should confirm this.  When the rotor magnets pass the shorted coils currents will be induced into the coils to make the coil and it's core "disappear."

So there is a possible mechanism for the speed up just like you stated - less rotor resistance because cogging and radial stresses nearly eliminated when coils shorted and no power transferred into the zero-ohm "load."

I made reference to the motor being a complex electro-mechanical impedance.  There is a good chance that the motor has two or more stabilization points with respect to the RPM.  So you got a speed up with the short, and that resulted in the motor "landing" at a different speed stabilization point.  That is not an unusual phenomenon at all.

Cheers,

MileHigh

[Magluvin]

Synchro1:

I tried for 15 minutes on Google to find any references to bifilar coils used in electromagnets and could not find any. 

Hmm. Im not even going to look.  Back when I was just introduced to the series bifilar coil, I did searches and all it came up with was bifilar relay windings, audio transformers and switching supplies, etc., and finally pulse motor coils on youtube. There are many search results for them, I tell ya what, be back in one min.... I just Yahooed 'bifilar coil and got over 215,000 results.  A relay coil is an electromagnet and some are 'bifilar'. In this case, one winding is finer wire than the other. A rated current needs to be applied to both windings in parallel in order to get enough field to pull the contacts closed. Once pulled the heavier winding is disconnected while the thinner winding remains connected to the on source till the relay is no longer needed to be on.

It is a way of saving power if a relay is intended to be on for long periods. They were used in LARGE relays I used to work with at Union Switch and Signal. The contacts are carrying large amounts of currents so the spring to unload the contacts is pretty strong, so a decent amount of power is required to pull the contacts together. But the 'holding' current is much less once the contacts are already pulled shut. So energy is saved by switching over to the thinner winding once pulled. Some of the boxes were 40 footers holding many racks of relays, so saving on power was a wise decision. These switch boxes were for railroad and subway controls and signaling, all vital equipment as lives depend on them. So running the relays cooler in these situations is preferred also and provides higher reliability.

Lets just call them 'series bifilar coils'. As 'pseudo' , as you like to describe it means pretend, fake, or sham. I asked you the other day what you meant by pseudo. Its your way of discrediting bifilar coils, as we understand them to be, described by the great Tesla himself in his patent way back in 1893. You are the only person I have ever heard the term from. So now that everyone is on the same page, lets just describe them as series bifilar coils. SBC if you like. Or SB  Series bifi, as I have found that others that have experience with them get what Im saying right away. But using pseudo, quasi seems to have 'us' asking, what do you mean. 

And Quasi  'resembling' 'having some, but not all of the features of' is still a bit of a negative term to apply to something that is held of higher value by others.

And even 'true' bifilar. Describing some different winding than what is being discussed as if what we are discussing is false in comparison.

Do you find it hard to believe that I or even we might take notice to these things?

Your version of a 'true bifilar' verses our 'fake coils' 'sham coils' 'pretend coils'. I know you will no holds barred put all you can into 'talking' points of why these coils are useless compared to True coils.  Common man.

Can you see what Im getting at with your clever choices of wording and how some might take it, if they take a close look at what you are saying?

Mags

[MileHigh]

Magluvin:

I have no problem calling them SBC's and that's a lot easier to type.

But I have to state strongly you are wrong about my use of the term "pseudo."  "Pseudo" is also a technical term and it in no way is it meant to be, or is it an attempt to be, derogatory.  It's never been an issue.  It just means "looks like" in this context.  The truth is SBC's don't even look like bifilar coils and I just used that term anyways.  It's just because of my desire to distinguish between two completely different coil configurations.  The uncertainty stresses me out.

No doubt you will find references to bifilar coils if you search.  But the links will be about "true bifilar" coils.  I was looking for junkyard electromagnet SBC's and came up zip.

MileHigh

[Magluvin]

From what Im just beginning to understand more recently is that the SB in Teslas pat is intended as an electro magnet, and that when input is applied, the capacitance increase 'within' the coil neutralizes the self inductance of the coil so current flows much faster right from the start thus producing a stronger magnetic field.  After all, the output property of an 'electromagnet' is a magnetic field. So the objective is a stronger magnetic field.

MH may be right about the coil resistances reading the same in the SB configuration. I have to test that myself. But the initial field production is much quicker from the beginning because currents flow much quicker due to the 'internal' capacitance. We cannot compare that to just adding a capacitor to a coil ad call it the same. A normal coil is going to take in what its given as the impedance allows over time.

In the case of the nail with wire wound on it, if there is more capacitance within the bifi coil compared to the normal wound nail, then the SB nail could result in more field due to this current input rush as compared to the impeding, slower building, normal coil.

It is said that if you attach a magnet to a metal bar and measure the holding strength before release right away as compared to leaving the mag on the metal for a longer period of time, the one that was there the longest will have the stronger hold. So if the inrush of the bifi is stronger initially than the normal coils full current, then the nail could have a stronger field even once the SB coil settles to full constant current flow. Especially if there are metal objects to be picked up added to the end of the core(nail) 'initially'.

I would imagine that 'if' the sb coil can pick up more staples or paper clips well after the sb coil is connected to the battery, then it should pick up even more if the nail is already in contact with the staples before the current is applied. This is just my thoughts on it before doing tests.

And then there is the indisputable lowering of resonant freq with the added capacitance that is what I am interested in also.

Then there is their use in a transformer. What would be the effects if the capacitance is built into the coil(in the transformer) rather than external? I have a n ecore prepped for my home made litz winding I will be making this weekend to see. The litz will be made with 7 strands stretched out between 2 mixing sticks and then then slowly twist the stick on one end til it is wound into one wire. And all the ends will be ready for capacitance readings to get things as balanced as possible. And a 7th strand to test out shorting  along the way. So testing of the sb in the transformer as a primary and as a secondary will be done.

Mags