At 01:09 PM 5/26/2003 -0400, you wrote:
>Hmmmmm,
>        Anyone have a schematic or documentation on designing an SCR
>control for this size of motor?

See if you can get ahold of the old GE or Motorola SCR manuals. But really
all you  have to do is alter the trigger angle with a PIC pulse from the
zero crossing to get the equivalent of the circuit you drew (no feedback).

>It sounds like the DC motor is exposed to a fully rectified unfiltered
>AC wave.  Does it not matter to the motor?

The motor doesn't care so much. It can be lovely and smooth (as my
lathe and mill DC motors)

>Wouldn't it be better to have a filter cap?

It makes the whole thing a lot more complex, for a little improvement.
The cap is rather expensive, subject to high ripple current, and you've
already run into the issue with inrush.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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