Posted 29 Mar 2021 Hi all, I'm having an issue with one of the Kinetix6000 allen bradley servo drives on a filling line that I support. This particular servo motors controls the rotary movements of a series of pumps to ensure accurate dose timing. Every time that I start up the machine, the PLC (Controllogix L7 firmware v28) executes a homing sequence to ensure the servo finds its 0 point. However, the servo in question keeps getting an 'Overspeed Fault' (E55). So far in troubleshooting, we've basically changed every component. We replaced the drive, feedback cable to the drive, and even hooked up a new free-spinning motor directly to the drive. Every component change has resulted in the same Overspeed error shortly after the homing sequence starts. To try and rule out a mechanical issue, I even disabled the homing sequence in the PLC and tried to move the motor using Motion Direct Commands. Immediately after a MSO command, the drive faults out for OverSpeed even with no motion. The last bit of troubleshooting we swapped the position of two of the drives, but the same OverSpeed fault happened on the drive connected to the rotary movement motor. At this point, I'm even considering changing the sercos fibers and the Kinetix power rack. Has anyone experienced anything like this before, or have advice on what to try to make it work? Thanks in advance for all your help Share this post Link to post Share on other sites
Posted 29 Mar 2021 Question 1 - Was the system running normally and malfunctioned or is this a new installation? Question 2 - Have you checked your setup parameters? - I had a servo one time where someone fat fingered the max speed to 200 mm/sec and the move speed to 1800 mm/sec. Everytime it tried to move it was over the limit until we changed the limit to 2000 mm/sec. Question 3 - I'd check and make sure you don't have noise in the system. This might cause what you're seeing. Share this post Link to post Share on other sites
Posted 29 Mar 2021 7 minutes ago, BobLfoot said: Question 1 - Was the system running normally and malfunctioned or is this a new installation? Definitely not a new installation, we just had an outage (unfortunately it was a 6 year major rebuild) so you can imagine how many things were touched :). 9 minutes ago, BobLfoot said: Question 2 - Have you checked your setup parameters? - I had a servo one time where someone fat fingered the max speed to 200 mm/sec and the move speed to 1800 mm/sec. Everytime it tried to move it was over the limit until we changed the limit to 2000 mm/sec. I looked at what I think are the parameters and none of them seemed to have changed. I even deployed an old version of code to make sure that someone didn't change anything and we're still having the issues 10 minutes ago, BobLfoot said: Question 3 - I'd check and make sure you don't have noise in the system. This might cause what you're seeing. Any thoughts ? Thats what it sounds like to me too, but we've changed out the feedback cable and even put a free-spinning motor connected to new cables on the drive and immediately got the same error. Share this post Link to post Share on other sites
Posted 30 Mar 2021 An overspeed fault is caused when the motors actual speed exceeds 150% of the maximum rated speed. This 150% point is the lesser of the two between the motors rated speed or the axis maximum speed setpoint. More than likely if this has been running for some time now it is possible that someone has "accidentally" lowered the maximum speed setpoint in the axis properties. There is also a chance that the integrator programmed a SSV to automatically change the maximum speed in a certain condition. But that would be unusual if none of the hardware or gear ratios needed to change. I'll attach a couple of pictures... Share this post Link to post Share on other sites
Posted 31 Mar 2021 Do not remember which one, however it is a setting issue, check the settings. Share this post Link to post Share on other sites
Posted 31 Mar 2021 This is going to sound like I think you're real green @seanp123 and I don't mean to imply that at all. But it has been bugging me as I read your post. The Kinetix 6000 is a multiple drive rack based system where the first card is the power supply for the rest and sometimes each drive has control or other power landed locally as well. Given it has run nuisance free for six years I'd look at changing the Power Supply and checking any power sources external to the drives. Just a strange suspicion I have that the outage took out a nearby component, not one of the obvious ones. Share this post Link to post Share on other sites
