Re: [CAD_CAM_EDM_DRO] Digest Number 2382

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@...>
> 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