Scott Dorsey wrote:
Chuck Harris wrote:
Scott Dorsey wrote:
Chuck Harris wrote:
But that is exactly backwards from the way chokes work. As the current
rises, and the core approaches saturation, the coil starts to lose the inductance
enhancement provided by the core, and it approaches the inductance of an
equivalent air core choke. That is, the inductance *drops*, and the inductive
reactance *drops* and the AC current shoots way up.
That makes perfect sense to me. So how _do_ current-limiting chokes work,
then? I always assumed they worked as I described but I may well be wrong.
On DC, they can't! No way, no how.

Right, but I was thinking that in the position where that coil is in
the circuit, it's directly in series with the AC coming off the transformer.

On AC, a choke can limit the current by being a reactive component...
kind of a lossless resistor for AC.

But! Swinging chokes always reduce their inductance when the current
rises. They typically have a 100:1 change in inductance over their
design current range.

How does the reduced inductance translate to higher series impedance?

It doesn't.

Where did you get the idea that such an inductor exists?

A swinging choke aids in the *voltage* regulation of a choke input
power supply by having a high inductive reactance at low currents (where the
supply would tend to be too high in voltage), and having low inductive
reactance at high currents (where the supply would normally tend to droop.)

Is that what you are thinking of?

-Chuck