Re: [CAD_CAM_EDM_DRO] small amp recommendation needed

Chris Stratton wrote:

> > > Actually, he wasn't modifying the audio amps at all as the kind of
> > > frequencies he wanted to use were within the audible range.
> >
> > HMMM? Is this a linear motor, like out of a hard drive? Most DC
> > brush motors have so much inertia, you don't get any response other
> > than audible tones when you go much over 25 Hz.
>
> The motor apprently has quite impressive frequncy response. It's a
> little brush servo motor, maybe a tad smaller than nema 23. He's
> verified the amplitude of motion at the frequencies of interest with a
> mirror and laser pointer, measuring the length of a line projected on
> the far wall of the room. While the audio amp lasted, the system was
> working for him. In operation, it sounds a lot like a mistuned servo
> loop - I keep thinking I've messed something up when he runs it while
> I'm working on the motion system in!

Gee, there are special motors made for this kind of service, but the
ultimate is a "mirror Galvo". Basically two fine wires suspended in
a big magnet, with a little mirror glued to the wires. The current flows
one way in one wire, and back in the other, so it swings the mirror.
I have a couple of these salvaged from oscillographs, if you are interested.

Jon