Linear PM Generators

[Matthew Jones]

Does anybody have any reference to the construction of a linear PM generator. I am specifically curious as to whether or not you need flux around the magnets and how the orientation of the flux may effect the performance of the generator.
I can find alot on the use of them but nothing on the design.

I was thinking it may not need flux. The wire might act like a copper pipe would when a magnet is drop through it. But at the same time I know a rotory generator without some flux does not perform as well as one with.

Any info or pointers to info would be appreciated.

Matt

[Ted Ewert]

Are you talking about something like a magnet oscillating through a coil core?

[dragon]

Does anybody have any reference to the construction of a linear PM generator. I am specifically curious as to whether or not you need flux around the magnets and how the orientation of the flux may effect the performance of the generator.
I can find alot on the use of them but nothing on the design.

I was thinking it may not need flux. The wire might act like a copper pipe would when a magnet is drop through it. But at the same time I know a rotory generator without some flux does not perform as well as one with.

Any info or pointers to info would be appreciated.

Matt

Hi Matt, A linear generator/alternator is exactly the same as a rotory except in how it moves. There are several variables that effect the outcome of it's performance... Number of turns, Area of the magnetic surface, revolutions per sec (ft per sec in the case of a linear ), Tesla of the magnets (flux intensity ) and number of poles. Which would bring us to the formula to find voltage output

NARBP x 2 = voltage

N = number of turns
A = surface area of the magnet in sq meters ( sq in x .000645 )
R = revolutions per second
B = Flux measured in tesla's
P = number of poles

A standard alternator could be used as a linear using a rack and pinion drive ( chain, cog or otherwise ).

Check out Windstuffnow for other details on constructing an air core PM alternator.
________
Mercedes-benz m272 engine history

[Matthew Jones]

Are you talking about something like a magnet oscillating through a coil core?

Like wave generators, from tide current. Or they are using them on struts in cars to gain energy from the rough roads.

Hi Matt, A linear generator/alternator is exactly the same as a rotory except in how it moves. There are several variables that effect the outcome of it's performance... Number of turns, Area of the magnetic surface, revolutions per sec (ft per sec in the case of a linear ), Tesla of the magnets (flux intensity ) and number of poles. Which would bring us to the formula to find voltage output
NARBP x 2 = voltage
N = number of turns
A = surface area of the magnet in sq meters ( sq in x .000645 )
R = revolutions per second
B = Flux measured in tesla's
P = number of poles
A standard alternator could be used as a linear using a rack and pinion drive ( chain, cog or otherwise ).
Check out Windstuffnow for other details on constructing an air core PM alternator.

I got all that, my problem is using flux outside of the permanent magnet. Or do I need to at all. And if so how is it orientated.
One way I was looking at was just to wrap a pipe with a light coat of metal. Then wrap the wire to produce the windings.
Or using epoxy and and either blacksand or iron dust.

But I can't find any info to confirm the use of a flux and how to use it.

Thats mostly what I am wondering.

I have built a small Shake Action generator that outputs DC but it was just plastic pipe and wire. It didn't put out much. So thats what lead me to the question about flux and flux arrangment.

Thanks
Matt

[dragon]

You basically need the flux lines to penitrate the coils. Most linear units are made by putting the magnets N to N and S to S. This helps expand the field around the poles and helps to focus the flux through the coils. The plastic tube - air core - is the easiest to build, I wouldn't use iron unless you plan to build a slotted silicon stator with some heavy duty runners.

Using round magnets with a center hole is the easiest way to set up the magnets on a push rod ( NSSNNSSNNS and so on ). The coils can be wound around the tube just like the shaker lites, the coil spacing should be between each pole. ( in the middle of the NN or SS) Everyother coil will be wired in reverse if they are run in series ( basic single phase). You can use 3 coils per pole and wire them in star for a 3 phase unit. The 3 phase would be smooth where the single phase would be jerkey as it passed each coil.

I've built a few different variations one of which is shown below.. similar to a dual rotor arrangement with linear bearings to guide the coil as it moved... The tube is far simpler in construction...
________
CHEVROLET S-10 BLAZER SPECIFICATIONS

[Matthew Jones]

Ok thats great. I can handle that. I just wanted to get ahead and not have to try to many variations to see what worked.

My idea was to use a plastic tube. I have thin magnets to use. They will be place with the north face pointing at the north face of the next magnet then its south pointed at the south at the next. This arrangment is outlined in a patent I found. The field actually protrudes further from the magnet then it would if directly pointed towards the outer radius. I have also confirmed this with tests and green film. Cast the magnets together with epoxy to make a piston. I can use the thing ones as my movement is only about 3/8 of an inch.

(If I had to, and I think now I do)I was going to layer the pipe with iron and epoxy mixed then wrap the windings around it. Ten do another thing layer of iron epoxy mix and wrap some more, ect.
Howard Johnson has patent that details encasing the wire in the flux core of a rotary generator. It was said to deliver higher amperage at lower speeds. Cross my fingers.

I am working on a model so I can for see my bugs and get a parts list. I'll try to finish the entire model with animation so people can see it. Its a genuine pieced together piece of tech.
TED will appreciate it for sure.

Thanks again
Matt

[Matthew Jones]

This is what I am working on. To drive it.
YouTube - ‪Bouncer.avi‬‎

The motor uses magnetic neutralization. I have been running a small rotary motor with that setup on it for a couple of days. They use nothing for power. A one coil setup is running on 36 volt 15 milliamp and it is running at speeds up to 5500 rpms with a small recollection of energy. The same speeds without the large magnet would be at 48 volt 1.5 amp.

The pendulum I have already tested. It came from the Chalkalis thread. 60 degree slice spins longer than a wheel or a straight pendulum.

Were going to capture the energy similar to the way Veljko Milkovic does with a two stage oscillator. I have already tested this part. A 1/3 pound pendulum spinning at 300 rpms gives bursts of energy at the bottom of the swing that are about 18 lbs of force. Its pretty incredible.
I'll incorporate springs under it and only use probably a 1/3 of the total force to try to drive a linear generator.

All the test look good I just got to get the generator built and everything else assembled.

Its a concoction for sure.

Matt

[dragon]

This is what I am working on. To drive it.
YouTube - ‪Bouncer.avi‬‎

The motor uses magnetic neutralization. I have been running a small rotary motor with that setup on it for a couple of days. They use nothing for power. A one coil setup is running on 36 volt 15 milliamp and it is running at speeds up to 5500 rpms with a small recollection of energy. The same speeds without the large magnet would be at 48 volt 1.5 amp.

The pendulum I have already tested. It came from the Chalkalis thread. 60 degree slice spins longer than a wheel or a straight pendulum.

Were going to capture the energy similar to the way Veljko Milkovic does with a two stage oscillator. I have already tested this part. A 1/3 pound pendulum spinning at 300 rpms gives bursts of energy at the bottom of the swing that are about 18 lbs of force. Its pretty incredible.
I'll incorporate springs under it and only use probably a 1/3 of the total force to try to drive a linear generator.

All the test look good I just got to get the generator built and everything else assembled.

Its a concoction for sure.

Matt

Pretty slick idea Matt ! I figured the linear alternator was for a pendulum project. Have you seen the other one that is using the linear approach in a different way ? Directory: Feltenberger Pendulum by Gravitational Energy Corporation - PESWiki ... also pretty ingenious. I built a small Milkovick unit to test quite a while back and it's pretty interesting in how it operates nothing spectacular from my little unit but it does show the concept.
________
CHEAP TSD SPORTS POWERED NON BLOWBACK AIRSOFT

[Ted Ewert]

I got a concoction for ya:

YouTube - ‪Solenoid Powered Pendulum‬‎

Check the rest out here:

Solenoid Powered Pendulum - Heretical Builders

Cheers,

Ted

[Ted Ewert]

@ Dragon, I love your linear generator! What was it constructed for?
The idea of opposing magnets across a thin coil is just what I was planning to do for a generator running off the end of a pendulum. I think that configuration is the most effective since it provides a very high flux density throughout the windings.

Ted

[Matthew Jones]

Pretty slick idea Matt ! I figured the linear alternator was for a pendulum project. Have you seen the other one that is using the linear approach in a different way ? Directory: Feltenberger Pendulum by Gravitational Energy Corporation - PESWiki ... also pretty ingenious. I built a small Milkovick unit to test quite a while back and it's pretty interesting in how it operates nothing spectacular from my little unit but it does show the concept.

Ya I seen the Feltenberger thing. He's fishy. Milkovick is not referenced in any of his work, but there is some clear correlation to back to Milkovick's work.

I got a concoction for ya:
YouTube - ‪Solenoid Powered Pendulum‬‎
Check the rest out here:
Solenoid Powered Pendulum - Heretical Builders
Cheers,
Ted

Ya I know you like them concoctions. Thats why I figured you could appreciate this idea when most would just scratch there head.

I figure if a self runner or some kinda super OU can exist its probably going to be in solid mix of technologies that are already working well.

Cheers
Matt

[dragon]

@ Dragon, I love your linear generator! What was it constructed for?
The idea of opposing magnets across a thin coil is just what I was planning to do for a generator running off the end of a pendulum. I think that configuration is the most effective since it provides a very high flux density throughout the windings.

Ted

That particular unit is a centrifugal generator. The alternators are held horizontal by gears while it's rotating and the mass of the coil and slide are allowed to simply move at will. At even a low rpm the mass is extreemly high and creates a considerable amount of force within the alternator to perform work. Unfortunately, it takes just as much energy to re-accellerate the weight as it shifts position vs what you can get out of the alternators. Fun project none the less....
________
ZX14 VS HAYABUSA

[rave154]

TED,

veryy nice build.

why not have a nice fat heavy neo as your "weight" / "mass"...and of course.,. the obligortory "pick up coils" placed convieniently by the side of the
path of the rotating neo on the end of the arm.....why not a series of coils.

youve got a nice way of converting linear motion into rotational there, whatever bearing ( or other assembly ) you placed at the fulcrum there....would have an immense force placed upon it though

seems nature just wont let us convert linear to rotation in an elegant manner

( as a thought that just occured to me....not to try and side track your ideas in any way...but since it seems that nature doesnt like the idea of us tryign to convert linear to rotation.....how about........rotation to linear?....im rambling now arent i lol )

[Ted Ewert]

Thanks Rave.
I'm still working on the best way to power the pendulum, so the generator portion will have to wait. I built a whole new configuration since that video was taken. I should probably start another thread instead of jacking Matt's.

Cheers,

Ted

[Matthew Jones]

Jack whatever you want. LOL I'm interested too.


@Dragon

What kind power did you get out of the linear generator in the picture and how fast did it go?

Thanks
Matt