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

[gotoluc]

Dont know if this thread has died out or not. Been thinking on it.

First thought is we have shown a couple ways to accomplish what is stated in the topic.  But they only show that there can be an advantage to using bemf, as most call it.
So from there one needs to build a motor that is very efficient to begin with. The output of the mechanical part is not in any of the equations so far. Rotors are not loaded and just free spinning.

When building a motor that is very efficient, meaning input compared to loaded output, the time frame for capturing collapse and reusing it has to be instilled into the design.  Pwm drive comes to mind where the coils are pulsed multiple times during a push and pull cycle and bemf is captured multiple times.
When we look at a chart curve of a coil building a field and taking on more current, as the curve just starts to level out, then we begin to input more and more as the curve flattens and the bemf becomes less and less as compared to the input total. So in my opinion it is best to cut the input while the current and field build is still on a strong vertical climb. Thats when the bemf will be closest to equaling the input of the cycle. For example, you could leave the input on for min or even hours, but still only get a very short period of bemf that does not build over that period of time.

My other thoughts on this are that the cap across the second coil design will be freq dependent in a much stronger way than using a switch or reed to fire the second coil from a precharged bank of caps charged by bemf. Just from studying the circuit in circuit sim with different freq inputs.

I have an electric bike that has an asymmetrical brushless motor where only 1 coil is switched to opposite polarity at a time, while all the others are on push or pull mode. A very smooth near zero cogging operation. The controller uses pwm to power the coils with varying pulses depending on the throttle input. The coils of that motor have thicker wire and less turns than the coils shown in my earlier vid. Possibly a virtual farm for capturing bemf.

If we were to try and capture bemf from say a standard dc, 2 brush, multiple commutator/winding motor, most of the windings for each com switch are in a steady on state and only one winding 'might' produce some bemf out. And a study of that is that there may not be much due to when the brushes are making a switch, they are contacting 2 commutator tabs at the same time, thus actually shorting a winding while the motor is running, causing large inefficiency in the motor to begin with. Big loss there, especially when the shorted windings are in the middle of the stator pole field, where pole switching generally happens.


So a particular motor design will have to be decided on in order to take the most advantage of bemf in my honest opinion. And if the initial motor design is up in the 90%, while being able to secure high amounts of bemf to recycle back into the motor function, I believe it can go over 100%

Mags

As far as I'm concerned the topic is still going. It's a little quiet now since I asked the guys to go to the flyback topic to debate things there.
I'm sure they'll come back once they've reached a consensuses.

This summer I played around with multiple on off time (per commutator segment) on a universal motor:  https://www.youtube.com/watch?v=pib2fpHRsaM

Luc

[Jimboot]

I'm going through reed switches like a knife through butter. Current draw down at 10ma on 12VDC. Simplest bloody pulse motor I've ever made. I'm measuring the flyback at several hundred volts though so it's probably that.

[tinman]

I'm going through reed switches like a knife through butter. Current draw down at 10ma on 12VDC. Simplest bloody pulse motor I've ever made. I'm measuring the flyback at several hundred volts though so it's probably that.

The average current may be 10mA Jimboot,but the instantaneous current will be much higher i would think. Lets say your  coil has a resistance of 10 ohms,and your running 12 volt's-thats 1.2 amp's of current flowing through your reed switch. If your coil is 50 ohms,that is 240mA through the reed switch. In order for there to be only 10mA through the reed switch,your coil would have to have a resistance of 1200 ohm's.


Brad

[gotoluc]

Hi everyone and Laurent (woopy)

I just watched Laurent's newest video: https://www.youtube.com/watch?v=TAx7Y0UIyHA
and decided to share my latest ideas and experiments with TinMan's RT : https://www.youtube.com/watch?v=n3IxLmdR9O0

Laurent (if you wish) please feel free to post your experiments in this topic as we may find this is all related.

I think there is two things going on when you bring the tungsten rod forward, one is the rotor coils resistance is less, so the flyback is more and the other could be the rod is now on the side Laurent has every second commutator removed (drilled out) and maybe the plasma is ionizing across two (series) rotor coils on with the flyback pulse (only) which may amplify the effect.

Also, I have found that after an hour or so of playing with a universal motor with the modified rotor in this configuration the motor starts to lock up which may be due to the constant magnetization direction.

All very interesting

Thanks for sharing

Luc

[Jimboot]

The average current may be 10mA Jimboot,but the instantaneous current will be much higher i would think. Lets say your  coil has a resistance of 10 ohms,and your running 12 volt's-thats 1.2 amp's of current flowing through your reed switch. If your coil is 50 ohms,that is 240mA through the reed switch. In order for there to be only 10mA through the reed switch,your coil would have to have a resistance of 1200 ohm's.


Brad

Aaah, thanks brad.