J
Jamie
- Jan 1, 1970
- 0
In our plant, we have a delta supply and do have periodic
grounding issues from machines having shorted heaters on them so,
now comes the next step. We now have some machines that have been
converted over to AC micro drives. (VS1MD). It seems that these
little machines will operate find in the shop/R&D area most of the
time 100% as expect how ever, we been finding that in some areas of
the plant they are not operating correctly..
They are giving random side effects. Things like the PID seeming to
loose control at random (Web Control) or the drive just seem like it
wants to not respond like it should while the feed back is getting
dangerously close to limit position and then it'll come to life and
over shoot! AFter that, the drive may over exceed correction and hit
the other limit. If it does not, it most likely will correct itself
and be happy with a normal acting control, again.
It would almost be like excessive load and the drive has insufficient
HP to control it how ever, it works fine in the shop. Today, It hit
me. In the problem area these units are being used, we do have a known
problem with the buss and happens to be a Delta that some where has a
random grounded leg.. We had to install isolation transformers in the
water system which is near by, which use Parker Drives (Eurotherms),
because they were spitting out Buss Over voltage errors, one actually
blow it's gutts out of the bottom! Don't know if that had anything to do
with it how ever.
I know most of you probably don't have experience with the
Baldor Micro Drives (VS1DM), but do you think this type of buss problem
could cause what appears to be firmware problems to actually be
ground loops screwing around with the control logic in the drive?
I just find it hard to believe with how many of these things out there
that poor software would exist at this level. On a second note, I did
find a reproducible error though! if you open the stop circuit, have the
dynamic brake come on, and vary the input reference to min/max and
back real quick, it puts itself back in run mode! regardless the state
of the RUN command at the terminals. I mean, even if you cycle the Run
terminal, it stays in RUN mode and operates in RUN mode.. This means the
operator can not switch off the drive, they have to kill power to the
drive!... what a dangerous thing!
Oh well...
grounding issues from machines having shorted heaters on them so,
now comes the next step. We now have some machines that have been
converted over to AC micro drives. (VS1MD). It seems that these
little machines will operate find in the shop/R&D area most of the
time 100% as expect how ever, we been finding that in some areas of
the plant they are not operating correctly..
They are giving random side effects. Things like the PID seeming to
loose control at random (Web Control) or the drive just seem like it
wants to not respond like it should while the feed back is getting
dangerously close to limit position and then it'll come to life and
over shoot! AFter that, the drive may over exceed correction and hit
the other limit. If it does not, it most likely will correct itself
and be happy with a normal acting control, again.
It would almost be like excessive load and the drive has insufficient
HP to control it how ever, it works fine in the shop. Today, It hit
me. In the problem area these units are being used, we do have a known
problem with the buss and happens to be a Delta that some where has a
random grounded leg.. We had to install isolation transformers in the
water system which is near by, which use Parker Drives (Eurotherms),
because they were spitting out Buss Over voltage errors, one actually
blow it's gutts out of the bottom! Don't know if that had anything to do
with it how ever.
I know most of you probably don't have experience with the
Baldor Micro Drives (VS1DM), but do you think this type of buss problem
could cause what appears to be firmware problems to actually be
ground loops screwing around with the control logic in the drive?
I just find it hard to believe with how many of these things out there
that poor software would exist at this level. On a second note, I did
find a reproducible error though! if you open the stop circuit, have the
dynamic brake come on, and vary the input reference to min/max and
back real quick, it puts itself back in run mode! regardless the state
of the RUN command at the terminals. I mean, even if you cycle the Run
terminal, it stays in RUN mode and operates in RUN mode.. This means the
operator can not switch off the drive, they have to kill power to the
drive!... what a dangerous thing!
Oh well...
