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

[gotoluc]

Thanks Gyula for bringing Hob's experiment to my attention.

It's all these small details we need to know and combine in or design that may lead us to the goal.

Luc

[MoRo]

...  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...

Good points. Newman's book discusses ways to achieve fast opens with less sparking. Maybe try parallel reed switches.

MagnaMoRo

[tinman]

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

But it is also true that by decreasing the number of turns while increasing the size of the wire,can also result in more copper used. The advantage of this is less resistive losses-ohms law rules.

The ultimate inductor would use square copper wire to reduce the air gaps between windings

I am half way through my Woopy replication-should be up later tonight.


Brad

[Magluvin]

Good points. Newman's book discusses ways to achieve fast opens with less sparking. Maybe try parallel reed switches.

MagnaMoRo

Hey MoRo

Thanks

That would be series on the reeds I believe. 'If' they open at the same time, the total gap possible is twice the distance as just 1 reed, to fully open in the same time frame. So the total gap gains distance 2 times as fast.  Would probably be best to make a spinning commutator switch in which many opening series contacts open at once, crating a super fast close to fully open situation.    Seems like a Tesla thing. Have to look that up.   

The reason for the commutator version is that reeds are not all exactly the same even from the same batch. There will be issues of magnets(of many on a rotor) not having the exact same field strength and or orientation as the others.  best to use tiny ones to avoid pole position discrepancies and just move the weaker ones out further to make up for field strength differences. But I would be way more confident in a well designed commutator with say 8 series switch points than 8 series reeds.  Dont get me wrong. Reads a very good. But they also can only work up to certain freq as resonance of the reed contact arms does interfere with keeping control of the on off times. Got a vid of that i think where the rotor slows in acceleration till it gets past that resonant point then surges further in rpm. Also happens at harmonics of the reeds resonant freq. So you get more than 1 resonance break through, as I remember I got at least 3 on my setup.

Good points MoRo. Never thought of the increase in speed of the contacts gaining distance from each other, only thought of the fact that the distance would be more.  Now that interests me more that the speed of the distance is increased with multiple switches in series.  Thanks for bringing that up.  Was probably about 6 to 7 years ago i played with the series reeds but didnt consider the speed till you brought it up.

Should probably make a thread on the subject.

Mags

[Magluvin]

But it is also true that by decreasing the number of turns while increasing the size of the wire,can also result in more copper used. The advantage of this is less resistive losses-ohms law rules.

The ultimate inductor would use square copper wire to reduce the air gaps between windings

I am half way through my Woopy replication-should be up later tonight.


Brad

Hey Brad

I suppose the idea of having 2 coils of the same dimensions and volume of copper but each having 2 diff sizes of wire, that they could produce the same field strength as long as the (P)ower dissipated into each is the same, where the smaller wire coil gets higher voltage input to overcome higher resistance and the larger wire coil gets less voltage to calculate the power as the same.  Makes sense.

The 24 coils on my lasersaber motor are in series. each are 42 awg 3200 turns at 15k ohm all in series. Seems like a large inductance would be had having a high rise time, but due to the high resistance the rise time seems almost instantaneous. Strange to experience.

They do make square enameled magnet wire.  Would probably do wonders for the capacitance of a bifi coil.

Mags