Tim's Magnet-Piston Engine Design

[gyulasun]

Hi Tim,

So far I have not had a look at the rotary version thoroughly because it was not fully clear for me for the first glance... Now that you redrew it, it is still not clear...  Would you clarify first:

1) finally there is or there is not any permanent magnet anywhere in it?
2) there is or there is not a shorted coil ?

In fact where are coil(s) in the new setup?  (I know there is the big coil all around the whole rotor and stator.)

As an addition, could you include the other coi(s) in the diagram (if there is any)?

This is not clear, I would like to understand your text from above post:

Remove the coil sections - so it's just repulsion between the iron rotor, and iron stator, then when the coil is powered, the two repel.   

So what repels each other when the coils are removed?

One more thing: the magnetic poles of the big coil are utilized or its saturating effect on the rotor (or stator) core is utilized?

Thanks, Gyula 

[tim123]

Hi Gyula,
  1) No - there are no PMs in it, just the iron.
  2) No - no shorted coil

There is only the 1 big coil around the outside.

The way it works is: When the coil is powered, the iron in the core becomes magnetised. The rotor and stator both repel each other because they are the same polarity. The rotor and stator both effectively become bar-magnets which run the length of the coil, of the same polarity - thus repel. (If you put 2 nails in a coil & power it up - they repel each other)

Pretty simple. When the power is switched off, they no longer repel (as much - there would be some residual magnetisation).

The big coil is therefore being used to saturate the iron.

So the power is switched on, just as the rotor goes past it's alignment with the stator. And switched off just as it leaves the stator - and is in alignment with the air gap.

I hope that makes sense.

[gyulasun]

Yes it makes sense now.

There's no movement of the flux axially in the coil, the question is does the rotation of the rotor inside the core, away from the stator bars somehow cause a generator effect in the coil? I'm struggling to see how it could.

-If the coil's powered up, and the rotor is turned - does it cause any change in inductance / flux - does it cause any faraday-law generator effect - in the coil?

Yes, I think it can cause a generator effect while there is input current i.e. Lenz law must be valid but this must be much much lower than in a conventional generator. Because the rotor becomes a moving magnet during the ON time of the main coil and when the rotor shaft is loaded in these moments, a reaction effect should manifest back towards the primary source i.e. input current.
I also think that using an L meter across the main coil to monitor its inductance while manually turning the rotor, you could see a change in inductance (albeit a small change I believe) whenever the rotor comes out from the covering hence the 'shielding' effect of the stator plates. I mean the stator plates hide the rotor from the coil when the stator and rotor just fully facing each other and as you rotate away the rotor from this position more and more 'iron' area appear inside the coil. This needs to be tested of course but that is how I think. Again, this effect is also a small one, far from causing as much drag as Lenz does in a conventional setup.

I think both the shape of the rotor and the stator should be optimized to get the biggest repel force between them.

rgds Gyula

[tim123]

Hi Gyula. Thanks for your input. I think you're probably right. It is something I think I'll have to test.

I would have thought that the rotor & stator I'd drawn were pretty much optimised already, so I'm intrigued as to what you might have in mind..?

Update... I've done a basic test. Air core inductor. 2 bits of iron for the stators, 1 fatter bit for the rotor. With the rotor in alignment with the stator ('shielded') 5.80mH, with the rotor at right-angles to the stator 5.85mH - so yes it does make a difference, but only a small one...

It definitely looks like an idea worth pursuing to me at the moment. Any advice etc. gladly received. :-)

[gyulasun]

...
I would have thought that the rotor & stator I'd drawn were pretty much optimised already, so I'm intrigued as to what you might have in mind..?

Update... I've done a basic test. Air core inductor. 2 bits of iron for the stators, 1 fatter bit for the rotor. With the rotor in alignment with the stator ('shielded') 5.80mH, with the rotor at right-angles to the stator 5.85mH - so yes it does make a difference, but only a small one...

It definitely looks like an idea worth pursuing to me at the moment. Any advice etc. gladly received. :-)

Well, just thinking of the repel force from the motor shaft direction: a mainly radially directed force is consumed by the sides of the shaft ball bearings unfortunately and the more tangentially you can direct the repel forces the more rotary torque the shaft can take up.  This can best be achived by 'slanted' facing areas on both the stator and the rotor.
So this means the facing areas should be slanted such a way that the forces between them are mainly in a tangentially direction to the rotor 'outside circle'.  If you need a simple drawing I will make one later.

Gyula

PS, Yes the change in inductance is small, even though in a real setup you envision the facing areas will be higher, causing a bit higher change: still small...