jouellet
Member
Hi Guys,
here is the setup:
application is crane. We have a 1336 Impact drive, with a 30 HP motor w/encoder and a dynamic braking system.
attach to that, is a little Micrologix, that only monitor the actual speed vs the commanded speed, and if the difference is greater that a certain preset, for 'x' amount of time, the Micrologix disable the drive. the drive will then immediatly activate the mecanical holding brake, that now acts as an emergency brake
normally, when the load is going down, we can see that the dynamic braking is working, and the load stops with no problem.
lately, the Micrologix keeps on disabling the drive, because the motor does'nt seem to brake in a timely manner
braking resistor/chopper has been proven good.
we called tech support, and they told us that the motor had probably changed its internal specification. we were told to try to do an Autotune on it. We tried the autotune, but it failed on the Flux test.
We then raise the current to 100 % rather than 50 % (as mentionned in the manual) same thing happened, we failed again on an "Hi Flux" fault.
we called tech support again, and based on those new information, we were told that the motor must be "dying slowly". I've never personnaly seen a motor "dying slowly" !!!
we then decided to place another 30 HP motor and try to do an autotune ( we don't have an exact replacement on hand...)
we entered the new motor's data, and tried the autotune. the Flux test that was failing before, started, but it lasted forever (I mean more than 30 minutes !!!) and never completed.
Tech support again, but this time, the guys was more confused then us !He wanted us to abort the autotune, and to enter the flux data manually, from the manufacturer's recommendation ! We wanted to prove that the drive was OK, not that we can run another motor ....
We went back on the crane, and one of the electrician did put his foot on the motor's shaft (that was still trying to do an autotune..) the motor then speeded-up/slowed down a few time, then told us that the autotune had completed !!!
WE are now all confused: can I assume that the drive is OK ? (I think so) can we blame the motor ? (my guess is Yes)
anyone ever experienced something similar ? any ideas ?
Tks
Jasmin
here is the setup:
application is crane. We have a 1336 Impact drive, with a 30 HP motor w/encoder and a dynamic braking system.
attach to that, is a little Micrologix, that only monitor the actual speed vs the commanded speed, and if the difference is greater that a certain preset, for 'x' amount of time, the Micrologix disable the drive. the drive will then immediatly activate the mecanical holding brake, that now acts as an emergency brake
normally, when the load is going down, we can see that the dynamic braking is working, and the load stops with no problem.
lately, the Micrologix keeps on disabling the drive, because the motor does'nt seem to brake in a timely manner
braking resistor/chopper has been proven good.
we called tech support, and they told us that the motor had probably changed its internal specification. we were told to try to do an Autotune on it. We tried the autotune, but it failed on the Flux test.
We then raise the current to 100 % rather than 50 % (as mentionned in the manual) same thing happened, we failed again on an "Hi Flux" fault.
we called tech support again, and based on those new information, we were told that the motor must be "dying slowly". I've never personnaly seen a motor "dying slowly" !!!
we then decided to place another 30 HP motor and try to do an autotune ( we don't have an exact replacement on hand...)
we entered the new motor's data, and tried the autotune. the Flux test that was failing before, started, but it lasted forever (I mean more than 30 minutes !!!) and never completed.
Tech support again, but this time, the guys was more confused then us !He wanted us to abort the autotune, and to enter the flux data manually, from the manufacturer's recommendation ! We wanted to prove that the drive was OK, not that we can run another motor ....
We went back on the crane, and one of the electrician did put his foot on the motor's shaft (that was still trying to do an autotune..) the motor then speeded-up/slowed down a few time, then told us that the autotune had completed !!!
WE are now all confused: can I assume that the drive is OK ? (I think so) can we blame the motor ? (my guess is Yes)
anyone ever experienced something similar ? any ideas ?
Tks
Jasmin
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