Hilden-Brand Magnet Motor

[acp]

Hi Jack,  For what it's worth, I did a few more simulations using FEMM, I really don't know if it's accurate or not, although I did manage to model Flynns idea successfully with FEMM which showed similar results to what people were getting in real life.

The new sims are using 8 Watts power in all cases. The side bar is as close to the magnet coil assembly as it will go in the program.


The first pic is using 8 Watts power to the coil with the magnet in place, You can see that the flux lines are denser through the magnet than through the iron sleeve, therefor the coil is not overloading the permanent magnet. 

Attractive force = 3008 Newtons







This second pic shows the same setup same power(8Watts to the coil), except the magnet has been replaced with a block of iron.

Attractive force = 3000 Newtons.






This third pic shows how you described I should do the test, that is with no magnet and no iron to replace the magnet, same 8 Watts power to the coil as the other tests

Attractive force = 1990 Newtons




You are right jack, that in comparison with the test with no magnet and no iron ( just the coil and iron sleeve) ther is less power than with the magnet in place.

What puzzles me though is that there is hardly a difference when you replace the magnet with the iron ( 8 Newtons difference), therefore in my eyes the magnet is superfluous. I am curious as to how this all adds up in real life as what I have done is just a computer simulation. I'm not trying to prove you wrong, I am genuinely interested.

It occured to  me that it would be very easy for you to machine a block of iron the same size as the magnet and run your holding test again, This also seems to be what you were asking advice about a few days ago (How much power would an electromagnet require to hold same amount as your valve etc.). I am just trying to help.

Best regards

Albert

[MeggerMan]

Hi Liberty,
The disc coil makes very little difference to the flux switching effect.
The simulation shows a very slight increase in flux density in the flux gate.

Standard arrangement with 15mA @ 0.1V


Disc arrangement with 15mA @ 0.1V


Disc arrangement with no power

Regards
Rob

[MeggerMan]

Hi Albert,
Yes, I have just run a lot of simulations with a gap to measure the force (0.001 inch).


So yes you can get a difference in force but only with a very narrow gap and at low energy levels, no where near enough to saturate the core.
So in conclusion it looks like there is a lot of force there but only under certain conditions. As a lifting magnet it is ideal, but for use in a motor, you need a very clever design to complete the magnetic circuit.
This is what I believe Jack has but cannot tell us until his patent is complete.

Regards
Rob

[Liberty]

Hi Meggerman,

Will your FEMM program calculate the back EMF in the magnet valve coil under motor operating conditions?  Or will it allow you to estimate the amount of back EMF percent difference between the two different shaped coils?  It would be interesting to see if the amount of back EMF is less with a narrow (tall) coil in the magnet valve, compared to a longer coil that goes the length of the magnet valve (solenoid coil).

Nice pics Meggerman!

Thought Jack might possibly benefit from this comparison?

[gyulasun]

Hi Albert,

Thanks for your simulations and may I ask you to include a fourth picture of the same setup when there is no 8W input to the coil and the permanent magnet is in place?  (Just for completeness and please include the force also.)

You conclude that the permanent magnet is not needed. Well, if you compare your first picture with your third one, it clearly shows that without the magnet the force is much less than with it. And do NOT compare this to the second picture when you replaced the magnet with a similar sized iron core!
Why? Because with the iron core in place you created a magnetic path much more flux conductive than in any of the other cases: the iron core has got a permeability much higher than either the permanent magnet or the air, so you created an electromagnet with more iron core volume than in the other two cases, ok?
So for me the conclusion from your simulations is that Jack's valve adds up the fluxes of the electromagnet and that of the permanent magnet. 

Regards,
Gyula

Edit: And your puzzle is answered by the fact that the iron core's permeability "supplied" (when you replaced the magnet with it)  the lack of flux coming from the permanent magnet (which sounds strange I know but if you try changing the permeability of the iron core in the simulation then you can easily 'tune out' the 8 Newton force difference).