VF-E brush motors reputation?

[wddanie]

I'm looking at a used, 1997 Haas VF-E vmc and have been told its different that other Haas mills since it uses brush servo motors. Do any of you have expereince with this machine? Is the reliability of the brushed motors adequate? Any other comments or things I should be aware of with the VF-E?

Thanks in advance,

Doug Danielson
Atlanta

[NC Cams]

Make sure that Haas will still service the motors.

I heard that one version of their servo motor they won't service any more and cores are hard to find.

[gar]

060214-0852 EST USA

wddanie:

I would avoid a machine with brush type DC motors.

We have a 1994 VF2 with these motors and moderately early on had motor and in turn controller failure. This resulted from carbon accumulation from brush wear.

For whatever reason the HAAS controller was very sensitive to this shunt resistance to ground. My recollection is that HAAS had a specification that this shunt resistance could not be less than 1 megohm, may be it was 100,000 ohms. In either case it does not take much carbon buildup to get into this resistance range.

I believe the brushes were probably too soft.

The motors can be rebuilt.

We have not recently had any problems, but this suggests I should check shunt resistance before we have a controller problem.

Certainly machines by mid 1998 had brushless servos.

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