Sharing ideas on how to make a more efficent motor using Flyback (MODERATED)

[Magluvin]

May be Luc could tell us where exactly he is looking for "more energy"? I tried to measure the energy in the spikes (more an estimate than an exact measurement, but it gives an order of magnitude) and it was not much.

I am not criticising Luc, I just want to understand and to measure the energy in the fly back spikes. Where is the magic? Or better said, where does Luc hope to find the magic? Any speculation is accepted and I will try to measure it in an "equivalent circuit". It can not be, that a motor is absolutely necessary? Or does it have to be a motor? I also accept that the magic is in the motor, but where in the motor, for sure not in the spikes.

Greetings, Conrad

It doesnt have to be just a spike when it comes to bemf capture. Look at a switching supply.  They are generally very efficient. So we have an in and an out, but we also want to turn a rotor with the magnetic field developed in the supply.  If we can do that and not have the addition of the rotor affect the original in out of the switching circuit, then we may have something good.


Mags

[Magluvin]

Another way to use the bemf to create more rotor energy is to just put a diode across the drive coil and shorten the input on time. The recycled collapse current will temporarily accomplish more push or pull time on the rotor after the switch is open.   To see the effect well the drive coil should be very low ohm and say 2mh and up. Will need a diode of decent current capability.

Some relay data sheets will describe the time delay of opening of the contacts when using a snubber diode to recirculate field collapse currents. In a relay application, it wouldnt be considered an energy saving advantage as relays are not really designed to be high frequency devices. More just on now, off later, etc.

Mags

[verpies]

I am not criticizing Luc, I just want to understand and to measure the energy in the fly back spikes. Where is the magic? Or better said, where does Luc hope to find the magic?

I don't think he ever told us to find "magic" in the "flyback" spike.  He just made an experiment that showed that energy in this spike can perform useful mechanical work.

I, however, think that there is no "magic" in the interaction of an ideal coil with a permanent magnet.

If there is any "magic" to be found, then I would expect it to be in the motor interaction between a coil and a soft ferromagnetic, because its domain alignment energy can be recovered in the "flyback" pulse at TDC.  With a permanent magnet - it cannot.

[verpies]

It doesnt have to be just a spike when it comes to bemf capture. Look at a switching supply.  They are generally very efficient.

Yes and the most efficient ones use synchronous rectifiers or Schottky diodes with low voltage drops.

So we have an in and an out, but we also want to turn a rotor with the magnetic field developed in the supply. 

To maximize the distance x mechanical force acting on the rotor by the "assistance coil" (L2), the current through L2 should flow as long as possible...not for several microseconds of a typical "flyback" pulse.  The L2 and diode D3 makes this possible.

[tinman]

I don't think he ever told us to find "magic" in the "flyback" spike.  He just made an experiment that showed that energy in this spike can perform useful mechanical work.

I, however, think that there is no "magic" in the interaction of an ideal coil with a permanent magnet.

  With a permanent magnet - it cannot.

The opposite is actually true.
Having permanent magnets on the rotor actually increases the efficiency of the motor in two way's.
First,the magnets actually generate a current within the drive coil,and this is additive to the inductive kickback output energy-so the inductive kickback output will rise.
Second,the power consumption (P/in) will also drop when a rotor with magnets is used,as apposed to there being no rotor at all.
This is of course using a non ideal coil,as we cannot make an ideal coil.

If there is any "magic" to be found, then I would expect it to be in the motor interaction between a coil and a soft ferromagnetic, because its domain alignment energy can be recovered in the "flyback" pulse at TDC.

The problem here is that it takes energy to align those domains in the first place,so there will be no gain to be had this way.

Brad