continuous looping in fkern

["shazanaz2000" <smartmicro@xxxxxxxxxxx>]

hi,

I'm doing some small fea analysis. my pc is a celeron500 with 64mb 
memory. My problem is not more than 100mm x 100mm planar. mesh size 
varies from 0.1mm in some blocks to 5mm in air. total node count is 
around 18k to 30k (depending on mesh sizes).

The problem I face is:
sometimes..., fkern loops for an inordinately long time without 
upgrading the newton iteration counter while continuously looping 
in "matrix construction" and "conjugate solver". If I stop fkern and 
adjust my file (I move any one or two node points or change the mesh 
size -slightly- at any one place) the next time fkern completes. this 
I've noticed in not one problem but in many. Am I doing something 
wrong? is my computer slow? I've even seen the NI count decreasing!!
Is that supposed to happen?

One more question please. 
my project is like a permanent magnetgun. I need to apply an 
attractive force of 250 Newtons on a projectile (iron/steel) about 
100mg weight from a min. distance of 1mm away from the surface of the 
magnet. What would be the size, shape and any other properties of the 
permanent magnet (NdFeB) required to do the job? the shape (of both) 
is adjustable. The projectile is never less than 1mm away from the 
magnet.

Thanks prem for enlightening me.

Shiv