On Jul 7, 2:42 am, Camilo <camilo...@[EMAIL PROTECTED]
> wrote:
> Ok, but in the practice, leaving aside formulas; on an industrial
> electromagnet which have all the design conditions to be strong, =BFis
> it only strong to hold, or is strong to attract too?
In short, a magnet attracts iron based upon the rate of change with
distance of the magnetic flux flowing through the magnet and attracted
piece. As you move a piece of iron away from a magnet, the air gap
that appears acts like a "resistance" to the magnetic "circuit". This
means that as the air gap is increased, the magnetic flux flowing
through the magnet and lifting piece "magnetic circuit" is greatly
reduced. The greater the distance the greater the reduction. Therefore
Electromagnets tend to hold items with a LOT of force when the gap is
small or nearly zero, but do not "attract" items from a distance very
well. It is possible to adjust these things but as a general rule that
is true. Just go find any magnet and stick a piece of iron to it.
Clomped on to the magnet it will stick with lots of force. But at some
distance the force of attraction will be much less.
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