'Rose-Tinted Lenz' Generator...

[tim123]

Hi Folks,
  here's another idea... I call it the 'Rose-Tinted Lenz Generator' - or RTL - for a bit of a laugh... Diagrams attached below. It's unusual in it's design, so forgive me if it's not immediately clear. As always it's open-source tech - put out there to see if it stands up to scrutiny...

The point is to have very little Lenz-force / back-emf applied to the rotor. Instead the Lenz-EMF generated by the coils is directed to other generator coils. So the coils are basically 'duelling'...

It's a rotary generator, with fixed stator pieces, and a rotor driven by a separate prime-mover.

The stator units consist of two 'duelling' coils and a permanent magnet in the middle - which is the initial source of flux - all joined into a magnetic circuit by a rectangular laminated steel / ferrite / amorphous core. There could be any even-number of stator units in the generator.

The rotor is simply made of mild steel or cast iron. It's about as thick as the PM in the stator, and has 'teeth' on the outside - half the number of stator units. So if the generator has 4 stator units, then it has 2 teeth on the rotor. So there are always two sets of coils in the generator...

The point of the rotor is to provide an alternative flux path for the permanent magnet. So as it rotates in the path shown in the diagram - the teeth come close the the PM, and it's flux moves out of the stator, and into the rotor. The rotor teeth only come near the PM in the middle of the stator - not the coils, and not too close to the stator cores either.

So unlike most generators - the rotor is actually removing flux from the coils - instead of forcing it in - as it approaches.

Now we get to the interesting bit, what happens as the rotor approaches the stator, and when it leaves...

As the rotor moves towards the stator:
- the flux moves out of the stator and into the rotor
- the coils attempt to oppose that reduction in flux - by providing the opposite polarity
- so in the diagram below the magnet is S-N, the coils will go N-S to try and 'bring the magnet back'
- so - the 2 coils' fields further strengthens the apparent loss of the S-N magnet - via a positive-feedback mechanism - and they drive each other to saturation

As the rotor moves away from the stator
- the flux moves back into the stator
- the coils attempt to oppose that with the same polarity - i.e. S-N
- thus the +ve feedback works again - driving the coils to saturation

Note that:
- the amount of flux 'removed' by the rotor isn't crucial - it just has to provide a modulation in the flux.
- that small change in flux is amplified by the EMF of the coils - because of the *load*
- positive feedback drives the whole stator to saturation in each half-cycle (but only under load).

The power is actually provided by the load itself.

The rotor *is* subject to cogging, and in fact - there is a mechanism for a reaction against the rotor:
- As the rotor approaches the stator, the coils cancel out the PM's field - thus no attraction on approach
- As the rotor leaves the stator, the coils reinforce the PM's field - thus extra attraction on exit.

However, i don't think this is a problem because:
a) the rotor/stator could be shaped to only come near the PM - and not the stator core. It would still 'soak up' the magnet's field - but wouldn't be near the core's field
b) it only has to modulate the flux. It's not providing the power. So the rotor can be quite a distance away from the stator.

What do you think?

PS: I think you can add bits to the rotor, and make it drive itself... Because the core field is varying as the coils strengthen & weaken the PM's field - that could be used to drive the rotor round. The rotor would have to have extra bits designed to be attracted to the core - and they'd have to be designed so as not to complete any part of the magnetic circuit.

So - it even drives itself. Maybe I can get it to make tea and toast too...

[tinman]

Sounds like it works much the same as my L.A.G (lenz assisted generator)
http://www.youtube.com/watch?v=Tv8SGxWNELo

[tim123]

Hi Tinman. Your L.A.G. looks totally different to me TBH. I'm not sure I understand it's principle of operation though - the vids all seem to indicate you'd explained it elsewhere...?

RTL has:
- No moving magnets - plain steel rotor.
- Bucking coils driven by the load.
- Rotor is removing flux from stator - not adding it - on approach.
- Stator magnet isn't providing significant output power - it's just 'priming' the coils.

Of course, there's plenty of room for me to have got part of his wrong. It does look like the load is powering itself.

[tim123]

Attached are some more diagrams. This is an alternative, and much better, arrangement. On the left is a side view of the stator unit, showing how the rotor bars move past the magnet. On the right is a view from the front.

Here, the rotor 'teeth' are arranged across the rotor. This means they rotate across the width of the magnet - instead of it's length. Much better. They could be made of mild steel bar stuck through an MDF rotor.

I'm not sure if the bucking coils arrangement is going to work as I think it ought to. It seems a bit too good to be true. It's not difficult to test the stator unit's principle though, and I will, probably tomorrow.

Even if the 2 coils don't work as hoped, a single coil with magnet in the same arrangement could still be a useful building block to an OU generator.

I think it could still deliver OU with just a single coil because:
a) the rotor sees very little of the varying flux in the core - as it's only overlapping the magnet.
b) If the magnet saturates the core at the point where it joins, where the rotor passes, then the rotor won't see any flux from the coils(?)
c) the varying flux in the core can be used to drive the machine - with a few extra parts. Will post a pic soon...

[gyulasun]

Hi Tim,

I was going to ask you to make another drawing, showing your setup from a different view from what you drew in your first post when you posted the new drawings above, thanks.  Now I think I understand your setup just enough to comment.

Basically your principle sounds good to me but I think the problem is the closed magnetic circuit for the stator: the poles of the magnet would be naturally closed into the either rectangular or the triangle stator shapes so trying to influence this closed magnetic circuit by the steel rotor bar to cause a decent flux change in the stator may prove difficult, just because the air gap between the rotor and stator.

I am not saying it is impossible to influence the flux in the closed stator circuit from outside i.e. by the rotor bar, I just refer to the much higher willingness for the permanent magnet to keep most of its flux in the stator cores which just closely touches it versus jumping to the passing bar with the air gap.  Just think of  Flynn's parallel path setup: when you bridge one side with a keeper, then another keeper at the opposite side would not stick (or maybe a very little),  unless you remove or lift up the first keeper a little i.e. you brake the closed magnetic circuit first.

To reduce this problem, you may wish to use air gaps between the permanent magnet and the stator cores instead of the direct touch but even so the full flux available from the permanent magnet could not participate in the useful induction. However, this latter would be but a small drawback of course.

You mention cogging in this setup and it could be solved by using a mirror imaged setup and fasten the rotor shafts together.

In your first post, for the rectangular drawing, you mention the coils as bucking coils. What do you mean on that, beyond the normal Lenz effect in them?

Greetings, Gyula