R: formula needed

[Barry L Klein]

Must the two components be physically isolated?  Could you just use a
solenoid?
Also, you might want to investigate magnetic latch manufacturers.  These
often consist 
of a coil assembly (the electromagnet) and a metal plate.  You could have
them
do all the calculations for you and just use their coil.

Barry

----------
From: 	Raoul Raffagli[SMTP:Raffa_Raoul at iol.it]
Sent: 	Thursday, August 10, 2000 2:00 PM
To: 	Paul Perry; synth-diy at node12b53.a2000.nl
Subject: 	R: formula needed

Yes, I know, it's true, but I think a magnetic camp is the best way to
solve
my problem. Need to attract a very light metallic plate at about 1 cm. I
think it's no good to make a magnet that needs a kW to do this, so instead
o
"trying" with high power I should calculate the right geometry and the
energy required. It's quite a difficult problem, I know, but it's very
important; instead of attracting it, it would be good too if i cuold push
very fast, and the fastness must be controlled by current. I thougt of a
air-pressured system (electronically driven), but doesn't seem so good
'cause it would make too much noise. MMMhhh, I must work a lot to solve
it.
Thanks,
    Raoul

----- Original Message -----
From: Paul Perry <pfperry at melbpc.org.au>
To: Raoul Raffagli <Raffa_Raoul at iol.it>
Sent: Thursday, August 10, 2000 2:36 AM
Subject: Re: formula needed


> At 10:30 PM 9/08/00 +0200, you wrote:
> >Hi all. Planning a new project that includes also mechanical parts
> >electrically driven. I need to calculate what kind of electro-magnet I
must
> >use and what current does it need to attract a metallic plate at a
certain
> >distance with a determinate force.
>
> The shape of the plate, the geometry of the magnet make a difference.
> It is very difficult to attract anything at a distance, because the
> power falls off as an inverse square approximately.
> You will get a good idea by experimenting with a permanent magnet.
>
> paul perry Melbourne Australia
>
>