"Hank Zoeller" wrote in message
...
Hello,

Can power supply filter chokes be used beyond their stated current
ratings? Are they typically rated for continuous duty? If so, if used in
ICAS service can I draw more current than rated?

For example, I have a choke rated for 5 Henries at 400 MA (25 Ohms). I'd
like to use it in a circuit drawing up to 650 MA peak. This would be for
a class C amp -- CW only.

Thanks for any input.

73,
-HZ


You're proposing to run the choke at more than 150% of its current rating.
That will have at least two very adverse effects.
First, you could overheat the windings to the point of burning insulation on
the windings, burning the wire open, causing a fire, etc.
Second, you're running the very possible risk of saturating the core,
causing major loss of inductance. The effect this would have on your
circuit depends on its actual component values and how well the rest of the
circuit can forgive the loss of inductance.
My recommendation would be to get a choke of the appropriate ratings.

That said, you should download a copy of Duncan's power supply designer from
http://www.duncanamps.com/psud2/index.html and input your component values,
load it with a stepped constant current load and see how it performs. This
program will show you the current and voltage waveforms and values, but it
won't show the core saturation effects. You'll need more sophisticated
software for that (Spice).

Cheers
--
HAM AND EGGS -- A day's work for a chicken, a lifetime commitment for a pig.

Dave M