Re: Digest Number 2382

I am also considering using an older mill (mid 1970's?) autonumerics
positool cnc ? I assume I would have The same problem with the servo
amps being that old (I was told that the older controllers could be
temperamental but they weren't specific). I am new at trying to do
this, so I was wondering the best way to start and what I will want
to keep and what I won't need (losing alot of garage space) I would
like to use the old servo motors if practical because I have a few
extras. How would I check if it has a encoder or resolver? Also
would I still be able to use the old power supply for the servos if I
got or made new servo amps. I am planning on making it pc
controled. Any help to get me started would be appreciated.

mike langeweg

--- In CAD_CAM_EDM_DRO@y..., Ray Henry <rehenry@u...> wrote:
>
> Bosong dai
>
> There are three small problems with these GE drive amps. They were
good
> solid performers but this many years after manufacture their
settings will
> drift a lot. Some of them I've had to tune twice a year in order
to get
> acceptable performance while making shallow tapers on a lathe or
while
> running one axis very slow on a mill. It is possible to replace
the
> capacitors on these boards and they will work like new.
>
> The second problem is that some service guys don't clean the motors
when they
> replace brushes and after a while an arc path develops across the
brush
> holder to the frame of the motor. In time this path will short the
motor bad
> enough that it will burn up the output current sense resistors and
the NPN
> transistors that drive the motor. For a few years I had to replace
them so
> often that I carried spares in my tool box.
>
> The third problem is that GE was so paranoid about someone stealing
their
> designs or setting up repair facilities that they remarked all of
the chips
> and transistors with paint right over the original numbers. This
may cause a
> small problem with some of the maintenence of these devices.
>
> The biggest problem with a retrofit for this age of machine may be
the
> resolvers that were probably used to sense axis positiion. The
newer servo
> motion interface cards accept quadrature encoder signals rather
than resolver
> sine waves. If your mill uses resolvers, you can get around this
with
> separate converter cards or by replacing the resolvers with
encoders.
>
> HTH
>
> Ray
>
>
> >    From: "genview1" <genview1@y...>
> > Subject: Can a GE550 servo driver be used with PC based controls?
> >
> > I have an old CNC mill with GE550 control, the servo motors and
AMPs
> > (in GE550) work fine, I like to retrofit it with PC based
controls.
> >
> > 1. Can the motors and AMPs be used with new controls.
> > 2. If so, which control or software can work better with these
olds?
> > 3. what type input the AMPs take?
> > The AMPs are as follow:
> >           ATDCIB  44A394619.G01
> >             BD NO 44B3923389.001        
> >                   44B394757-002/7
> >
> >           ATDCIA 44A394619.G01
> >           BD NO 44B392389.001
> >                 44B394757-002/4
> >
> >          ATDCIA 44A394619.G01
> >            BD NO44A392389.001
> >                 44B394757.002/6
> >
> > Any suggestions and infos about these AMPs will be great
appreciated.
> >
> > Thanks.
> >
> > Bosong dai