Re: Servo amp connections needed. Where should I go from here?

Well Hello Fitch,
Long time no type to,
I had been on the Alt.CNC and Rec.Crafts sites but really got fed
up with the BS that goes on there.
Kind of new here also. Glad to see you here and willing as usual to
offer assistance.
Thank you for your input. It seems to follow suit here with my
doomed trickery. I will see if I can locate a tach and then try again.

Doug

--- In CAD_CAM_EDM_DRO@y..., Fitch R. Williams <frwillia@m...> wrote:
> On Tue, 29 Jan 2002 06:46:29 -0000, "sleyed" <Sleyed@a...> wrote:
>
> > There is no tach on the motor I am using.This is a mishmash of
> >parts.I was trying to simulate the tach input at the same time as
the
> >signal hoping it would null out somewhere near zero volts on each
> >input. It may be a case where I need a slight negative to null it.
>
> You can not have a speed servo with out some sort of feedback
> proportional to the motors speed. A servo controller in the
traditional
> sense is a feed back control loop. Eliminating the feedback means
it
> isn't a servo any more. Simulating a tach signal that isn't derived
> from some signal proportional to rpm will result in a runaway
servo. It
> will go to max, or min, but it will "not" regulate to a constant set
> speed in response to load fluctuations.
>
> Fitch