Partnered Output Coils - Free Energy

[TinselKoala]

TK:

Yes thank you for reminding me about that.  Of course that would be kind of tricky to do and it is "dumb" with no negative feedback.  I believe a big fat MOSFET car audio amplifier is essentially the same thing but it includes the magic of the negative feedback.  So all of the "MOSFET linear region balancing" is hidden inside a black box and you don't have to worry about it.  The differential pair output from the audio amplifier can be a current sourcing and sinking beast that will hold the voltage to whatever the input says the voltage should be.  At least that's my understanding of it.

Also, to be "truer to the spirit of working on the bench" I seem to recall that you posted some nice schematics where a standard op-amp drives a complimentary pair of power transistors to give you a high-current op-amp.  But heck if a $100 car audio amplifier gives you a MOSFET-based 150-watt power servo amplifier (wild guess) that's pretty tempting.

And I will have no stupid snarky comments from Synchro1 please.

MileHigh

Yes, that's right and it's simple to do, thanks for reminding me. The slight complication here is that one does need a bipolar power supply for the op amp and the power transistors. But if you have a dual PSU that can be put in series mode, or use two batteries, that's easy enough to arrange.

I've demonstrated this circuit both driving a motor load (M), and of course driving a coil in the "MescalMotor". I don't know what the maximum frequency response is though, but it will certainly handle the low audio frequencies that seem to be "preferred" here.

The transistors should probably be on heatsinks if you are going for high power thruput. For low power you can use any NPN-PNP pair, just about. I used BC337-25 and BC556 in the MescalMotor coildriver. Or 2n2222a and 2n2907.  The 741 op-amp is common and cheap as the dirt it's made from.

[conradelektro]

I don't get your usage of the 100-ohm resistor on the function generator side. Shouldn't it just be one ohm or even 1/2 ohm?  In other words just a current sensing/viewing resistor?  The power input to the circuit is the RMS voltage across the 60-turn coil times the RMS current as measured with the voltage across the current sensing resistor.

I do not like to connect my function generator to something without a current limiting resistor. I know it has an internal resistance of 50 Ohm, but I do not want to overload it. Therefore I have chosen a 100 Ohm resistor as a shunt (instead of a 1 Ohm resistor).

This was a first test, just to see if something strange happens at low power.

The real test will be with my mono audio amplifier as I indicated in my last post.

I am making an assumption that at low frequencies the current and voltage will be in phase.  Also, to be a bit more precise, with your existing probe placement, the AC voltage across the 60-turn coil will be the AC voltage measured with channel 2 minus the AC voltage measured with channel 1.  Again, I am assuming a one-ohm or 1/2 ohm current sensing resistor, not a 100-ohm resistor.

Yes, current and voltage (at the input side) were in phase at 50 Hz, but at 1 kHz and higher there was a shift, may be 10 degrees.

How would I measure the shift at the output side, since the Voltage over the load resistor is at the same time the Voltage Drop and the Voltage over the output coil?

You should put component designations on your schematic (R1, R2, L1, L2, etc) to make life easier when discussing your circuit.

Your transformer itself looks great.  Note as a (hopefully) interesting exercise, you can take your analysis one step further because you measured all of the coil resistances.  So you can measure your power dissipation in the coils themselves.  I am "keeping it simple" here and assuming a sine wave excitation waveform from your function generator.   In theory there is nothing to be gained by using a nasty square wave excitation waveform.

Will try to remember component designations in my next diagram.

My next tests will be with sine wave excitation by help of my mono audio amp (12 Watt max).

Thank you for your help, greetings, Conrad

[synchro1]

Jerry Bayles shows how two balance magnets, fields opposite on a bar and axle, align parallel to the axis of two Chiral magnets, and 90 degrees to the perpendicular on the other side. It would be interesting to see if a pair of balance magnets would behave the same way on either side of the two opposie poles of "Bucking Coils" supplied with DC curent.

[TinselKoala]

I do not like to connect my function generator to something without a current limiting resistor. I know it has an internal resistance of 50 Ohm, but I do not want to overload it. Therefore I have chosen a 100 Ohm resistor as a shunt (instead of a 1 Ohm resistor).

This was a first test, just to see if something strange happens at low power.

The real test will be with my mono audio amplifier as I indicated in my last post.

Just be sure to always provide a proper impedance to the output of the amplifier to avoid blowing the output transistors.

Yes, current and voltage (at the input side) were in phase at 50 Hz, but at 1 kHz and higher there was a shift, may be 10 degrees.

How would I measure the shift at the output side, since the Voltage over the load resistor is at the same time the Voltage Drop and the Voltage over the output coil?

The "assumption" is that a resistive load will produce no phase shift between voltage V and current I on the output side. To confirm this, connect a 1R CVR in series with the load resistor. Connect both probe references to the coil side of the CVR, and the "I" probe to the load-CVR connection. The other "V" probe to the other side of the load resistor where it connects back to the coil set. Use the minimum wiring lengths you can arrange, including the probe references, so that you aren't adding inductances to your test setup.

Will try to remember component designations in my next diagram.

My next tests will be with sine wave excitation by help of my mono audio amp (12 Watt max).

Thank you for your help, greetings, Conrad

[MileHigh]

Conrad:

Certainly using a 10K trimmer pot will work on the amplifier input.  It looks like that amplifier module has an built-in voltage inverter that takes the power supply input and generates the opposite voltage.  I can't read German so I am assuming this.  So if you connect a +12-volt power supply to the module it generates -12 volts internally.

Going back to using the function generator as the only drive source, I seriously doubt that it can be damaged by driving a low impedance load.  However, do not rely on my advice, if you are curios check with experts like TK, MarkE or Itsu.  I am pretty sure that your function generator has a servo-amplifier output stage that connects in series with a 50-ohm resistor before the signal goes to the outside world.  So the function generator amplifier itself never sees a short if you were to short the output.  i.e.; If you short the output it sees a 50-ohm load.  The real way to destroy the function generator output would be to connect an external high voltage source to the output terminals.

Going back to your input power calculations, I want to emphasize that you were calculating the power going into in the 100-ohm resistor, and not into the 60-turn coil.  So if you wanted to do another function generator test and keep the 100-ohm resistor that would be fine, but you still have to calculate the power going into the 60-turn coil.

MileHigh