AC servo motor burning out 1 phase (motor side) but ok VFD side Discussion ThreadAC servo motor burning out 1 phase (motor side) but ok VFD side Electrical Advice
Hi all,
First post, so not sure how this will work out…
I’ve currently got a 3 phase AC servo motor (Lenze brand) at work that seems to be overloading 1 phase (U phase of motor)…
This motor is VFD driven by again a Lenze brand 9300.
The load for the motor is a coupling driven pressure roller, with another identical motor/vfd/load setup above for identical application and use when needed.
As far as I’m aware these motors have always been fitted and always driven by the same VFDs…
During inspection some time ago after a catastrophic motor failure I found all phase terminals meggered to earth and terminal box burnt to hell. So decided to replace for the same identical motor…
Fast forward 6 months or so and on routine maintenance found the U phase of the replaced motor terminal was starting to become brittle and discoloured, tested the motor windings and all balanced at 1.4 ohms and meggered fine between eachother and to earth.
After a thorough inspection of the VFD side terminals, no burning or discolouration was showing and all connections tight.
After checking parameters on the Drive, all fitted the spec of the motor and as explained above, have never been touched or adjusted.
During running conditions checked VFD output to motor and all ampages showed roughly balanced (as expected with a balanced motor) reading were U- 8.6A V- 8.5A W- 8.75A.
Checked mechanical load and pressure roller bearings were free to turn by hand…
Getting abit stuck now with paths to go next, and don’t want another motor burn out.
Any advice would be greatly appreciated.
Thanks in advance.
AC servo motor burning out 1 phase (motor side) but ok VFD side for the original thread on Electricians Forums
Hi all,
First post, so not sure how this will work out…
I’ve currently got a 3 phase AC servo motor (Lenze brand) at work that seems to be overloading 1 phase (U phase of motor)…
This motor is VFD driven by again a Lenze brand 9300.
The load for the motor is a coupling driven pressure roller, with another identical motor/vfd/load setup above for identical application and use when needed.
As far as I’m aware these motors have always been fitted and always driven by the same VFDs…
During inspection some time ago after a catastrophic motor failure I found all phase terminals meggered to earth and terminal box burnt to hell. So decided to replace for the same identical motor…
Fast forward 6 months or so and on routine maintenance found the U phase of the replaced motor terminal was starting to become brittle and discoloured, tested the motor windings and all balanced at 1.4 ohms and meggered fine between eachother and to earth.
After a thorough inspection of the VFD side terminals, no burning or discolouration was showing and all connections tight.
After checking parameters on the Drive, all fitted the spec of the motor and as explained above, have never been touched or adjusted.
During running conditions checked VFD output to motor and all ampages showed roughly balanced (as expected with a balanced motor) reading were U- 8.6A V- 8.5A W- 8.75A.
Checked mechanical load and pressure roller bearings were free to turn by hand…
Getting abit stuck now with paths to go next, and don’t want another motor burn out.
Any advice would be greatly appreciated.
Thanks in advance.
AC servo motor burning out 1 phase (motor side) but ok VFD side for the original thread on Electricians Forums
