Re: [CAD_CAM_EDM_DRO] What have I got ?

In a message dated 11/20/2002 9:02:38 PM Central Standard Time,
davemucha@... writes:

> would I be correct in assuming that what I have are a couple rather large
> inductors ?<<

Yep, Dave, that'd be what they are. "Chokes" are used for "smoothing" to
preclude need for HUGE capacitors, and/or to relieve "starting-current
stress" you'd have without inductors (caps only). Chokes can be made of
useful size (Henries) for lower currents, but they become physically large
and very expensive if inductive value in Henries remains "up there", and
current gets large. I have never built a power-supply, myself, with a choke;
only READ about this.

>
> Luckily, the third unit is a transformer. I need to do some testing to see
> what ratios it has.
>
> IF the large unit is an inductor(choke?) does it have any value in a power
> supply ? or anything else for that matter ?<<

It can be useful to "smooth" the "pulsating DC" you get out of the rectifier,
if sufficient # of turns (Henries), and it is wound with large enough wire to
carry the current you will be drawing from the supply, IF it's net DC
resistance is not much. But you still need capacitance; anywhere from 500
to, oh, 1000 µF per ampere. You might do with only 500 µF per amp if the
choke has perhaps a half-Henry or more of inductance. I have never had
opportunity to "tinker" with a choke, as I say, so I'd just have to
EXPERIMENT, were I asked to give a definative answer.

Jan Rowland



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