jimlux wrote:
Anyone have a cookbook approximation kind of equation for the hoop
stress in the primary? Or even, a single turn coil, given di/dt, etc.
I think that the stress on a single loop (or a coil) can be calculated
as follows:
1- Obtain an expression for the inductance of the coil as function of
the length x of the wire: L(x).
2- The energy stored in the loop with a current i is: E=0.5*L(x)*i^2
3- Differentiate the energy in relation to x. This gives the force along
the wire: F=0.5*i^2*dL(x)/dx
If the inductance is expressed as function of other parameter, as the
radius of the coil, the
length of the coil, or the gap length in a coil with core, the same
formula gives the force that
tries to change the parameter.
(I wrote "I think" above because I could not locate this idea anywhere
to use as reference...)