plchacker
Member
I'm sure that most of us have experienced trouble similar to Timothy's post on a servo drive.
Just curious, what are some of the most unexplainable you have seen?
After replacing a DC motor, the machine ran without a hitch for two weeks exactly, no trouble.
Then two weeks almost to the minute, the drive went into runaway for no good reason. Two seconds later $80K of parts were toast. Six good technicians called for help 24 hours later. A control guy from the west coast showed up. Two days later we were all scratching our heads, no progress.
Somebody says out of the blue, "Hey, lets reverse the field windings and see what happens." It ran, but with the labels clearly indicating that the field windings were reversed. The drive ran for ten years and never had a similar problem again.
I was watching it when it went into runaway. No one was near the controls. It went into runaway in mid cycle.
This was TTL logic, and Hg wetted relays. Parts were almost non-existent even then. (Before the days of runaway safety controls)
Just curious, what are some of the most unexplainable you have seen?
After replacing a DC motor, the machine ran without a hitch for two weeks exactly, no trouble.
Then two weeks almost to the minute, the drive went into runaway for no good reason. Two seconds later $80K of parts were toast. Six good technicians called for help 24 hours later. A control guy from the west coast showed up. Two days later we were all scratching our heads, no progress.
Somebody says out of the blue, "Hey, lets reverse the field windings and see what happens." It ran, but with the labels clearly indicating that the field windings were reversed. The drive ran for ten years and never had a similar problem again.
I was watching it when it went into runaway. No one was near the controls. It went into runaway in mid cycle.
This was TTL logic, and Hg wetted relays. Parts were almost non-existent even then. (Before the days of runaway safety controls)