Chris Loiacono wrote:

> simple method to rectify the AC, then phase control the 1/2 sine-shaped
> pulsing DC with a single SCR. This seemed like it was worth investigating
> for 2 reasons: low cost and; I have many phase angle ciruits and code
> snippets to simply plug in.
>
> So, why do I get the ugliest and unsteadiest speed control this way?
> It's a simple low-side scr phase angle controller as I described above with
> a non-sensitive gate 8 Amp device on a < 2 A PMDC Gear motor..


Do you have a big diode across the motor? Have you
checked the phase angle is steady with a CRO??
Do you have a high enough load inertia for a 60Hz
pulsed DC system? :o)
-Roman

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