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

[gyulasun]

Hi everyone,

here is a new demo video of the GTL Flux Gate with a better comparative test then my first attempt which I deleted.

The test starts with the scale showing the pull force of 2.6Kg from the permanent magnets which are imbedded in the MOT (GTL Flux Gate)

Test 1: I power only the Low impedance coil (0.4 Ohms) with pure DC to establish a baseline to have a comparative for the 2nd test.
Results are: with an input of 2.20vdc @ 4.3a = 9.5 watts, the low impedance coil can alleviate 2Kg of the PM pull force.

Test 2: I power both the low impedance and high impedance coil connected in series (93 Ohms) with the flyback diode connected across the series coils.
Results are: with the pulse circuit at 235Hz / 50% duty cycle with 60vdc @ 0.151a = 9 watts the high impedance coils can alleviate the same 2Kg of the PM pull force.

The results are not as spectacular as I would of hoped for but how can we explain Test 2 with such a high coil resistance to perform the same task with 1/2 a watt less input by adding components that represents only losses. pulse switch, high impedance coil and diode?

Link to video: https://www.youtube.com/watch?v=2k3iGi9VPCU

Luc

Hi Luc,

The only explanation to your question is the much more number of turns for the 93 Ohm MOT coil than the 0.4 Ohm thick wire MOT coil has.  The high number of turns can insure a similar excitation for the core at a lower current level  compared to a coil with low number of turns at a higher input current level.

The 93 Ohm coil resistance dissipates 2.1 W power (0.151A*0.151A*93).
The 0.4 Ohm coil resistance dissipates 7.4 W power (4.3A*4.3A*0.4). 
This may seem surprising but shows 2 things: loss in a wire increases with the square of the current and high current can be circumvented by many number of turns in favor of getting less loss in a coil.  Of course in any particular case a trade-off should be chosen on the number of turns and the wire diameter.

Gyula

[MileHigh]

Hi all

I have tried the 10 ohm scr between the entry of the cap and the assistant coil (X4), the trace is much better but is at no place at zéro volt, so i think perhaps my probes or my scope should be recalibrated, so i stop measuring so small current with my scope to avoid junk datas. If somebody has a better equipment, feel free to follow MH recommendations for the measurement.

It's entirely possible that when you switch over to the 10-ohm resistor that you have a continuous current flow through the secondary coil.  Therefore there may be no problem at all with your probes and your scope calibration.  If you check the voltage across the 1 uF capacitor you may also notice that it never goes to zero volts.

The explanation for this is that the current pulses from the drive coil keep filling up the 1 uF capacitor with charge so that it never goes down to zero volts.  Therefore there is always current flowing through the secondary coil.

[gotoluc]

Hi Luc,

The only explanation to your question is the much more number of turns for the 93 Ohm MOT coil than the 0.4 Ohm thick wire MOT coil has.  The high number of turns can insure a similar excitation for the core at a lower current level  compared to a coil with low number of turns at a higher input current level.

The 93 Ohm coil resistance dissipates 2.1 W power (0.151A*0.151A*93).
The 0.4 Ohm coil resistance dissipates 7.4 W power (4.3A*4.3A*0.4). 
This may seem surprising but shows 2 things: loss in a wire increases with the square of the current and high current can be circumvented by many number of turns in favor of getting less loss in a coil.  Of course in any particular case a trade-off should be chosen on the number of turns and the wire diameter.

Gyula

Thanks Gyula for keeping the explanation simple enough for me to understand.

Even though today's tests are not so bad with the GTL Gate, yesterdays tests reveled I could achieve 2Kg. for pull force from a MOT (without PM)  using just the primary with only 3 watts of input. So for now the GTL Gate idea is shelved until something new come.
So I'm going back to my original idea of building a bucking MOT motor with the assisting flyback coil separated from the primary low impedance coil.

Luc

[Magluvin]

Running out of time here at lunch so dont have time to find the post by Brad I read earlier to quote.

Brad was talking about 1kv jumping across 1mm gap, suggesting that there wasnt enough to jump the reed at 60v.  What is missing there is the fact that as the reed opens, the tiniest fraction of a mm, the spark starts and continues to flow across the gap as it goes to fully open. Like if you set up a standard relay to buzz, 12v in usually can give 90v out. But while it buzzes, there are sparks across that gap. The initial spark when the contacts just open ionizes the air allowing the spark to continue even when the gap is opened more to its fully open state, then dies out.

Not knocking you brad. Just providing info that I know on the subject. 

Mags

[gyulasun]

Hi Luc,

In the meantime Hob showed a paper he and his colleague made on just electromagnets to increase their force, see attachment and then in his next post a video :
http://overunity.com/15796/elementary-physics-revisited/msg466245/#msg466245 

They introduced the force/power ratio, tested and compared 6 different coils and the conclusion is that

"The amount of copper in an electromagnet determines the force per power
ratio, not the number of turns or the wire thickness in the coil,  the more copper the greater force."

Well, interesting approach, I have not seen such comparison before, and "to my rescue"  I think the amount of copper is also increased when you increase the number of turns...(what I said)  and of course there are other factors to be considered.      

Gyula