Albert wrote in message
...
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

I know I can weigh it, provided it's not on a spool or motor winding
already.

My local electrical shop has a wire gauge, but it stops at 18 gauge.

A microscope might work, but ones that have calibrated distance
measuring on the eyepiece are expensive.

Perhaps a milliohm meter might be able to measure the difference in
resistance of a foot of it or so, but that's hardly a standard item
either.

Any suggestions?

I use either a dial calipers or a micrometer. But then the insulation
can make it sizeably larger than the value given in the wire tables.
The wire tables have a column which gives 'ohms per 1000 ft' which is
just another way of saying milliohms per foot. So if you measure ten
feet of 30 AWG it should measure 1.04 ohms. My cheap meter test leads
are something like .4 ohms, so it's really difficult to get any accuracy
at that low a resistance. I have a Leeds Northrup wheatstone bridge,
and it's not very good either at that low a resistance. So I put the
wire or whatever on a power supply and crank up the current to a quarter
amp, and then measure the V drop and calculate the resistance from that.


Thanks,

A