Maker Pro
Maker Pro

Stero Speaker magnets

J

Johnny

Jan 1, 1970
0
Are stereo speakers a good source of magnets to use in building generators?
 
A

Anthony Matonak

Jan 1, 1970
0
Johnny said:
Are stereo speakers a good source of magnets to use in building generators?

Generally, No but speakers vary so much it's anyones guess.

Anthony
 
J

Johnny

Jan 1, 1970
0
Anthony Matonak said:
Generally, No but speakers vary so much it's anyones guess.

Their size and weight seem like they would be good candidates.
Strength is also a consideration.
If I knew the formulae I could determine this for myself.
Anyone know the formula to determine how much induced current/voltage can be
obtained from a given magnet?
I imagine speed of rotation matters somewhat.
 
P

Pop

Jan 1, 1970
0
I don't know anything about the formulae, but I do know two
things that might be indicative. Or not <g>. Of something <g>.

The higher the "efficiency" rating on a speaker, the stronger the
mangetics. The better the speaker, the stronger the magnets.
Assuming of course, that the speaker uses mangets: Most do, but
some use electromagnetics in their design so it takes current to
create the magnetism.

Most speakers are also designed such that, to get the intended
power of the magnet, you have to have either the "ring" that
comes with it, or something that will achieve the same objective
for the shape of the generator location.
The ring is used to concentrate the flux pattern so that it's
strongest in the place where it's needed. Without it, they're
often pretty weak. Maybe someone here can fill in some holes on
this one. Actually, you might want to try an audio or hobby
group for more detailed information.

I've used a couple of high efficiency 6 inch mid-ranges to make
magnetic floor sweepers with. They work great, but if anything
gets directly onto the magnet itself, it can be a job to pull
apart.
Haven't found a good use for it yet, but I pulled apart a
drowned 15" woofer awhile back that you will -not- pull anything
off it with your fingers. Only prying with a sliding motion can
get anything bigger than a nail off it! it's surprising just HOW
powerful they can be, but, like I said, a lot of that strength is
the flux conduction design, not the magnet itself. Pull off the
flux conductor and that same magnet can't even hold its own
weight to a steel shelf. Interesting stuff.
I think I'd want to take some courses if I were going to try
to use them for a generator of some kind. But hey, that's just
me! ;-}

Pop
 
J

Johnny

Jan 1, 1970
0
Pop said:
I don't know anything about the formulae, but I do know two things that
might be indicative. Or not <g>. Of something <g>.

The higher the "efficiency" rating on a speaker, the stronger the
mangetics. The better the speaker, the stronger the magnets. Assuming of
course, that the speaker uses mangets: Most do, but some use
electromagnetics in their design so it takes current to create the
magnetism.

Most speakers are also designed such that, to get the intended power of
the magnet, you have to have either the "ring" that comes with it, or
something that will achieve the same objective for the shape of the
generator location.
The ring is used to concentrate the flux pattern so that it's strongest
in the place where it's needed. Without it, they're often pretty weak.
Maybe someone here can fill in some holes on this one. Actually, you
might want to try an audio or hobby group for more detailed information.

I've used a couple of high efficiency 6 inch mid-ranges to make magnetic
floor sweepers with. They work great, but if anything gets directly onto
the magnet itself, it can be a job to pull apart.
Haven't found a good use for it yet, but I pulled apart a drowned 15"
woofer awhile back that you will -not- pull anything off it with your
fingers. Only prying with a sliding motion can get anything bigger than a
nail off it! it's surprising just HOW powerful they can be, but, like I
said, a lot of that strength is the flux conduction design, not the magnet
itself. Pull off the flux conductor and that same magnet can't even hold
its own weight to a steel shelf. Interesting stuff.
I think I'd want to take some courses if I were going to try to use them
for a generator of some kind. But hey, that's just me! ;-}

Pop

Thanks.
Nice info.
 
W

William P.N. Smith

Jan 1, 1970
0
Johnny said:
Are stereo speakers a good source of magnets to use in building generators?

Hard Disk Drive positioners have very string magments in them.
 
J

JoeSP

Jan 1, 1970
0
Johnny said:
Their size and weight seem like they would be good candidates.
Strength is also a consideration.
If I knew the formulae I could determine this for myself.
Anyone know the formula to determine how much induced current/voltage can
be obtained from a given magnet?
I imagine speed of rotation matters somewhat.


What's the point? There are lots of better ways to do it without magnets.
If you just want to see it work, efficiency isn't important. If you want
efficiency, there are lots of cheap alternatives in the junkyards and
surplus stores.
 
B

Bob Adkins

Jan 1, 1970
0
Hard Disk Drive positioners have very string magments in them.

HDD magnets are so powerful and so much fun, it's surprising they aren't
illegal. :)
 
Top