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

[gotoluc]

I'm curious as to what pole gets projected out the ends of the I's without putting the keeper on top?

When the flux projects out it's the North and South of the Neo that goes through the I's. At this point the Alnico is in opposite poles and why the Neo's flux is projected out.

Also instead of draining that cap through the resistor use it to fire your coil and by doing so collect the flyback again and keep using it , it will diminish over time but thats when you hit it with a battery pulse to bring it back to the start.

Yes, flyback could be used to assist but it needs about 2.3 Joules of energy to magnetize the Alnico and each flyback recoveries are only about 0.1 Joule.

Can just regular ceramic magnets be used ,I don't have any others except one big neo ring magnet?

I don't know and haven't tried it with ceramic magnets. Give it a try and see.

Luc

[gotoluc]

Nice work once again gotoluc!

On the Robert Murray device, I wonder how much shorter you can cut the Alnico magnet? I wonder if soft iron spacers will let you get away with a shorter Alnico and smaller coil so you can use less power to switch it?

I think it's all relative, less magnet mass = less flux strength. As it is, if I shorten the pulse to the Alnico I get less magnetization force since some of the Neo's flux conducts through the Alnico if it's less magnetized. A longer pulse creates the opposite but obviously to a certain point, as once you reach the Alnico's maximum magnetization any more input is a waste of power.

Luc

[MagnaProp]

Does it take more energy to reverse the Alnico when the neo is uses as apposed to using no neo? I'm assuming it does.

I think it's all relative, less magnet mass = less flux strength...

Good point. If we cut the Alnico to short then it won't be strong enough to stop the neo magnetic flow. Hmmm

[shylo]

 When the flux projects out it's the North and South of the Neo that goes through the I's. At this point the Alnico is in opposite poles and why the Neo's flux is projected out.
So on 1 side of the coil 1 I is n , and the other I  is s?
It projects one pole on one , and the opposite pole on the other?
I'm using stored flyback to fire my coils to cause rotation, this might give better acceleration.
But like you say the amount of stored flyback is small ,compared to what you need to input for drive.
Every added coil produces alot more flyback, it's a doubling effect.
Looking forward to your further test's.
Thanks your a great contributor.
artv

[Khwartz]

Hello Luc, thanks for your experiment sharing

Don't we have to know the mass of the magnetic shunt and check at which height the U shape will lift it completely?

Let's say the barre is 100 g and you lift it up to stick it to the U shape, right when you approches it at 1 cm from the top while place on the table:

Weight Potential Energy in Joules =

{Mass in Kg} * {Gravity in m.s^-2} * {Distance, or Length, in meters}

= M [kg] * g [m.s^-2] * L [m] = W [J]

Let's say:

M = 200 g = 0.2 kg

g = 10 m.s^-2 (we only seek about orders of magnitude, so don't care for the "cents" )

L = 1 cm = 0.01 m

W [J] = 0.2 kg * 10 m.s^-2 * 0.01 m = 0.02 [J]

2 [J] of consumption of an impulse minus the flyback recovery (0.1 J), divided by 0.02 [J] of lifting energy = 100.

Thus the efficiency would be the inverted ratio: 1/100 = 1 %.

Thus the limit distance for over unity efficiency would be around, for 200 g of magnetic shunt:

L [m] = W [J] / (M [kg] * g [m.s^-2])

= 2 [J] / (0.2 [kg] * 10 [m.s^-2])

= 1 [m]

Am I missing something? Am I wrong your your numbers or my calculations?

Regards,
Didier