On Aug 19, 12:37*am, "N_Cook" wrote:
Is there an online calculator anywhere ? or failing that what sort of
"packing factor" for 0.08mm (+/- .005mm ) winding on a relay coil.
I have a good idea of the weight , subtracting an estimate of the plastic
former and this would give the length from the density of copper but number
ot turns ?.
Impregnated coil so cannot count-off turns
Rectangular section to coil , on the inside anyway, 14x 16.4mm , 16.8mm
width, outer layer is curved at "corners" and bulging (from the winding not
abuse) so more scatterwound than precise regular lay-up .
Outer dimensions of 21.4mm bulge / 20.3mm , or so, at outer edges one way
and 23.4/22.2mm , the other, a bit of geometry would give a good idea of the
volume of this space but what ratio of that volume would be copper and what
air+varnish, then what sort of weight would be contributed by the varnish?

I found that tables from wire suppliers are a great guideline. But,
nothing beats having to fight 'stacking factor' on your own.

I use 0.5 for wrapping 36 Awg enameled wire. I know I should be able
toget better than 0.7.

So take the winding area multiply by SF and divide by wire cross
section area and you'll get very close..

And, from experience, if there are a few layers, don't count on nice
neat, high density layering and stacking, doesn't work that way.

Oh, also watch out for stretching the wire, making it slightly thinner
and 'appear' to be able to put on more turns, you'vve actually reduced
the wire size instead.