Re: [CAD_CAM_EDM_DRO] Phase Control of SCR's; Hi Current

Jack,
There are some commercial DC power supplies which use a scheme similar to
what you describe, but on the DC side of the transformer. If you truncate
the sin wave on the primary (mains) side of the transformer, you will get a
funny looking sin wave on the secondary side at a much reduced power (due to
the transformer action). Say, if you cut off the first 10% of the cycle on
the primary, you get somewhere near 40% reduction in power on the secondary.
And yes, you are right. The engineers who design the power supplies I
mention above make $100K plus per year to do so. There is a great deal of
feedback design, finessing and testing to make such designs hold up for the
long haul. I'd stick with commercial stuff -- it's cheaper in the long
run.
Henry

----- Original Message -----
From: <jmw@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Monday, March 05, 2001 2:02 AM
Subject: [CAD_CAM_EDM_DRO] Phase Control of SCR's; Hi Current


> I know this is a little off-topic, but the talent level of the group
> is so tempting...
>
> Can someone steer me to a circuit for triggering SCR's at a user-
> selectable point in the AC cycle? I've seen circuit snippets in asst
> cookbooks, but not being an ee I'd like to find something a little
> more complete. The rectifiers will be working at 50v 250amps max in a
<<<SNIP>>>