Hanon,


I've been revisiting your like pole drawing and I begin to understand. It could work in a way similar to the BTT. But I think the outer core must be thinner than the inner core. And the  outer core must be saturated, otherwise the like pole paths may "parallelize" within the outer core and .ignore the inner core. (a rather controversal issue, if such parallelization does exist at all, that I tried to address in the AFA thread)


Regards

@marathonman: You got my emails?
sorry for offtopic

ANOTHER METHOD TO ALTER THE MAGNETIC FIELD OF AN ELECTROMAGNET

As far as we have been discussing we have tried to change the magnetism of the electromagnets by changing the current which circulates along each one. As we know, this system requires a variable resistance, I = V/R . This system is very inefficient because of the heat dissipation in the resistors.

We could also get a variable magnetic field if we change the number of effective turns (N) in the electromagnet.

B = nu·N·I / Length

Suppose that we build a electromagnet with 700 turns with 6 intermediate taps at 600, 500, 400, 300, 200 and 100 turns . If we feed sequentialy to each tap we will get a variable magnetic field in the electromagnet.

This could be got with a proper circuit (as a CD4017 + 555) and some transistors.

I have wonder many times why Figuera used 7 groups of electromagnets and, also,  7 intermediate resistors. Maybe he just drew in that way to clarify the concept but he built it in a different way to skip the heat dissipation... I don´t know

Regards

PS: Also I attach another sketch with the electromagnets with like poles facing each other. The swinging back and forth of the two magnetic field will produce a movement of the magnetic lines. When they collide, they are expelled from the core and in this movement the magnetic lines will cut the induced wire. Suppose a pancake coil or many parallel wires in between the two core sides.

In all dynamos and generators induction is done because the induced wire is cut by the magnetic lines. Just some food for  thought...

I agree with the resistors basicly being wasteful. The generator needs to overcome this loss, so it should output at least 200% of what the resistor grid delivered.


Using taps in the primaries seems to complicate things substancially, since the impedance of them is the "resistance to alternating current" that is highly dependant on frequency, meaning yor Ps will get diffrent supply, depending on the Hertz rate they're driven.


As the existing Resistor/Commutator devices are some great work, I would suggest to run them with minimal Voltage, eg. 0 to 1.5 V, and then simply use a stereo amplifier. There are some amplifiers that are very economical in power dissipation. Probably you should take care of the phase shift that the amplifer should not do. It may be most simple to use a car amplifer when you use a car battery already. They must be obtainable second hand or so for a few bucks.


An other amplifer would be this:

 sparkbangbuzz.com/mag-amp/mag-amp.htm


 

Hannon
  you will still need resisters to provide a small forward voltage to the inducer coils/magnets to prevent the field from the one which is "on" from totally backfeeding the one which is off.Once one magnets field swallows up the other two and all three coils become oriented the same, the time involved to switch back all three and the amount of current will be excessive as well. The collapsing magnetic field will have a high spike short duration that can be tamed if it passes through a resistance back to the common connection between the two inducers suppressing the consumption of the source.Glad to see your starting to think in terms of what makes a magnet stronger.
 I only used one meter lengths of conductors in bundles to keep wire resitance down to as low as possible. Using empty 22 caliber shells for terminal ends makes it a nice easy wind and connect up.Solder on one side ,wind then trim and place the other one on.Many thousands of turns able to handle lots of amps but only fed a few to establish a strong field to work with on the start up. The problem with using wire length to control consumption of current is you have greatly limited the amount of magnet you can create when you can no longer take advantage of higher currents. The only part that should get warm is the cores not the resisters.

If is transformer  with two secondaries like in picture, then one secondary then conected, then input power is small almost same, because magnetic flux go toother pach, but then we short other secondary, then bulb light in full brightness and input current go up.
Now if we put instead primary permanent magnet and on one secondary put load and magnetic flux go to pach there no load,then small, wery small power consuming motor rotates and shorts other secondary, then magnetic flux go from magnet to pach were not shorted secondary, with load, and using small energy possible change magnetic flax, there it go. Like VTA, using small power controling we big power, were it go.

btw the reason for make before break is to avoid large flyback spike taking out energy and destroying device, because current flow all around and returning back, today we can do it also with make &break or Tesla way going to HV, but dangers are still here.
Enough from me...

Two more things that I wanted to say.


First of all, several times I said (V*V)/ohms=watt. I had this from a socalled ohms law wheel, a circle with several formulas, such as w/a=v, v*a=w, etc. etc. I though this is all true since I had it from an engineering page.


Now it turns out to be crap. Why? I have a 25Watt, 230Vac lightbulb and it has about 200 Ohms dc resistance. So, (230v*230v)/200ohm= 264 watts...


So I apologize for posting nonsense, I did what many people do, I just repeated the things that some "obviously skilled" engineer said and most likely he also just repeated it. Lesson learned: question everything, verify everything personally.


The other thing is, what this whole Back EMF and Back MMF business all about? Isn't this the same?


No!


When you put DC current trough a coil, it creates a magnetical field. This magnetical field will induce a current into the secondary coil that's on the same core. It's inducing only when the field chanches, which means in AC always. Now, as soon as it has induced a current in the sec and we allow this current to flow, by means of logic this will cause a magnetical field in the core that opposes the one coming from the primary. This is the Back MMF or Back magnetomotive force, which is present at any time the current flows trough the sec. This bmmf is causing the prim to get "in phase" and start dissipating energy at all. We have to deal with it, probably like Thane Heins did.


The Back EMF on the other hand,  a term often used for the pulse caused by a collapsing field is the reverse polarity pulse in the electrical circuit of the coil that appears when the DC supply of a coil is turned off. Of cource, it also causes a magnetical field or pulse. It is the stored energy of the coil, just like the stored energy in a cap. Unlike the bmmf, the bemf does not appear when the voltage rises in the ac wave. the bmmf appears whenever there is a change in the sec current flow, the bemf is more of a rubberband that snaps back when released.


So I hope I made clear and proofed that bemf and bmmf are not the same. And that we have to deal with both of them.


Regards



BTW. for all those who are still having problems to understand why 2 coils bring a current 90° out of phase:
The inducer causes the magnetical field immediately, but the induced will only be induced when there is a change in the magnetical field. In a AC sine wave, there is most magnetical change when the inducer passes the zero volt line, and least change when it reaches the top voltage (both, positive and negative). This is why the induced will be in a 90° degree (or 25%) delay to the primary. I know this is basic stuff, but often not understood, esp. the part about the inducer acting immediately, but only the induced being delayed.