Jon Danniken wrote:
Winston wrote:
The inductance of that coil fell significantly when you lopped
off the 'I' core, yes?

Can you place a small value sense resistor in series with the
'common' line to your coil? The way I misunderstand magnetic
core saturation is that we expect a 'knee' where current begins
to increase in a nonlinear fashion in relation to applied
voltage. You could set your 'scope up as an X-Y display to
show this nonlinearity very clearly.

Okay, now that caught my attention, as I've been looking for a way to
"notice" saturation when driving the primary of a MOT.

I do know that one can view phase angle with an x-y viewing of current and
voltage, and I guess it makes sense to look at that same waveform for a
change as an indicator of saturation (when phase angle is changed due to an
increase of non-inductive current).

Thanks Winston, I'm gonna have to play around with this.

Shore.

For A.C. operation, I'd expect that a current transformer
would give you much better isolation and signal - to - noise ratio.

For D.C. (or A.C.) operation, I'd expect that a Hall Effect
Current Sensor would be a better choice, for the same reason.

I've used the Allegro ACS756 in some extremely low impedance
applications where a sense resistor caused power supply
instability.
http://www.allegromicro.com/en/Produ...0756/index.asp

Highly recommended, though you will need to normalize it's
output. (I did that automatically with DAQ gear.)

For seven bucks, it is a great value.

http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go _button&KeyWords=ACS756&x=0&y=0

--Winston