You're welcome.
What is the effect you're trying to achieve?
I don't think that there's anything about such
a physical arrangement that would be particularly
useful to construct in and of itself.
If you're just trying to couple electrical energy from
one coil to another you don't need to geometrically
arrange them akin to a rotor/stator type of arrangement.
That arrangement is just used in generators
because it's a physically spinning turbine that is being
pushed hard by a mechanical process that is doing the
work that is converted into electrical energy.
In motors it's used because it's the key point of
converting electrical energy to physical rotation energy.
If you're just looking for variable coupling of circuit
energies thatcan be done in a variety of ways without
a geometrical situation like that.
When I say coupled flux I do not mean to refer
in any way to a specific physical arrangement of
two coils, though geometry certainly does play
a part in dictating what the coupled flux will be.
Don't take this analogy TOO far (since it's inaccurate
in a lot of other ways) but JUST for the purpose
I am about to describe -- imagine there are two coils,
one is a shower-head and the other is a drain.
The geometry and physical materials
of the shower head and the environment it
is spraying into dictates the greometric pattern of
its spray. The amount of spray is dictated by
the flow rate of the water (current) going to the
shower head, and the current (flow rate) is driven
by the pressure/energy difference between the
pipe feeding the shower head and the space the
shower head sprays into -- that is the voltage.
So with a constant water flow rate (current) and a
fixed set of geometric and environmental circumstances
the shower head will always produce the same spatial
pattern of spray and the same flow rate of spray.
The spray of the showerhead is the magnetic flux,
and its spatial pattern of field density
(amount of spray passing through a given square inch
of space) is the main aspect one can measure it by
beyond its total quantity over all space.
Now position another coil (our 'drain hole')
somewhere in space. The drain hole will have a
certain size, a certain distance from the shower head,
a certain orientation angle relative to the shower head.
Depending on the factors of the drain's size/placement
and the shower head's spatial field density of 'spray'
(flux), some fraction of the flux from the shower head
may pass through the 'drain hole' that represents
another coil.
As is intuitively obvious, anywhere from as close to zero
as you could imagine to nearly the full amount of the
shower head's flux (spray) will pass through the
'drain hole' depending on the physical/geometric
factors I mentioned.
As is also intuitively obvious, if the shower's flux is
spread out at a very wide angle, it'll be very difficult
for much of its flux to pass through a drain hole if
the shower head isn't either right NEXT to the drain hole
in a face to face orientation, or even better, the shower
head could be stuck INTO the drain hole.
When the shower head is NEXT TO and FACE TO FACE
with the drain hole that's like two coils being face to
face and oriented in the best possible way to couple
given their separate positions.
When the shower head is stuck all the way into the
drain hole, that'd be more like winding one coil directly
on top of the other.
So the 'coupled flux' is just the total amoung of flux
that makes it down the drain hole given the setup
that exists.
The total flux is the total amount of flux emitted by
the shower head wherever it may go in space and
however much of it is coupled or NOT to the drain hole.
Any circuit in the universe has SOME mutual inductance
with any other circuit in the universe, but usually
unless they're RIGHT NEXT to each other or ON TOP
of each other, the coupling is very weak, as in a few
percent at best in many cases.
Even when they're literally on top of one another or
right next to each other, special design circumstances are
generally necessary to get the coupling factor to exceed
about 25%.
Now the inductance of a coil is how much
magnetic flux it produces for a given current flowing in it. This is an area where the shower head analogy breaks
down badly -- a shower head will emit the same flux
of water out as there's a flux (current) of water in the
pipe going into the head. In magnetics there's
a ratio known as 'the inductance' that determines how
much magnetic flux is generated by how much current
flowing in an inductor.
When I speak of mutual inductance, that refers to
the mutuality or coupling of current to flux between
two circuits. The 'mutual inductance' of the
shower head / drain is defined as the ratio of water
captured by the drain (the flux that goes THROUGH the
drain) to the total water current flowing in the shower
head. The current generates a certain amount of
total flux, but the MUTUAL flux is only that fraction of
the total flux that goes through the drain as opposed
to elsewhere.
So the coupling factor is coupled flux / total flux,
and the mutual inductance is
flux in the drain / current in shower head.
There's an important theorem in physics that says
that if you switched the roles of the drain and the
shower head, the MUTUAL inductance remains the same,
it's a mutual quantity, not one that's unique to going
from one direction to another -- that's another difference
in the shower head analogy to real magnetics.
R3KR said:
Thank you for the detailed explanation!
There would be a dc source on the coils. Each coil would pulse for a short period then the next would be charged (pulse). but fast, maybe 100 times a second.
When you say "coupled flux" are you talking about the point at which the coil and magnet (in a generator) go past each other and the flux (form the magnet) moves through the coil and causes a current to flow ?
