text: <s>[INST] PF 755 - Rod Torque measurement unestable Grettings We have in the field a PF755 drive connected to an 32 poles permanet magnet motor using the PCP oil well application. The motor runs unstable as if it has a fisical impediment in the bearing. The torque shown in the parameter 1166 vary from 0 to 300 to 0 again in a matter of seconds. Originally the drive was connected to an 60 poles motor. When we change in the drive the number of poles back to 60 the torque stabilize and the motor work fine until it reach 200 RPM when the problem star again. Is it possible the autotunne is not working propertly? We have done it several times an it never gave any alarms. The motor characteristics are: 380VAC, 37Amp, 27HP, 350RPM, 32 poles. The drive characteristics: PowerFlex 755 75 Kw. Thanks in advance for te response. [/INST] Hello, Thanks for sharing this problem. It looks as if the drive is being used within a Pump Jack oil well application. I am hoping this thread could be visible by other Engineers that have used the PowerFlex 755 drive on this particular type of application, very common I believe in countries with significant onshore oilfields. I do not have experience on this type of application. I can see a specific set of many parameters within the Applications File that should be carefully addressed based on the key mechanical elements of the rig. Equally, there is an additional feature called Pump Off, addressed to automatically change the speed of the pump jack based on torque feedback from the motor. The procedure to set up that feature is described in more detail on Appendix C of https://literature.rockwellautomation.com/idc/groups/literature/documents/pm/750-pm001_-en-p.pdf and assume the Motor Ctrl Mode to be InductionFV. Please note that there is no mention to permanent magnets motor when using the Pump Jack feature. There are also some specific relevant technical notes from the Rockwell Knowledgebase that address this type of setup/application as well. Please see below: PowerFlex 750 series drive Pump Jack setup guide PowerFlex 750:Pump Jack Pump-off Function and Setup Any comments from any Engineers with relevant knowledge and experience on this type of application shall be very welcome on this channel. Regards, \\n </s>