Mitsubishi Electric MELSERVO-J3 Series Instruction Manual page 380

11. TROUBLESHOOTING
Description
The servo motor 1. If the servo motor can be driven
vibrates. safely, repeat acceleration and
deceleration three times or
more to complete auto tuning.
2. Reduce the auto tuning
response (parameter
No.PA09).
(Except for the manual mode)
If the servo motor can be driven
safely, execute the adaptive
tuning.
If the servo motor can be driven
safely, execute tuning with the
advanced gain search on MR
Configurator, MRZJW3-SETUP
221E (C2 or later).
If the servo motor can be driven
safely, execute tuning with the
advanced vibration suppression
control.
Display the cumulative feedback
pulses in "high speed monitor"
command of "monitor" menu on
MR Configurator, and check if its
numerical value is skipping.
Check if there is a backlash on
the machine part.
Check the mounting part of the
servo motor.
Check the servo motor power
cable.
Check if the vibration varies
according to the speed.
Check the mounting accuracy of
the servo motor and machine.
Check the load for the shaft of the
servo motor.
Check the vibration from outside.
Check method
1. The servo gain is too high.
2. The auto tuning response is too high.
The machine is vibrating (resonating).
The machine is vibrating (resonating).
The load side is vibrating.
Feedback pulses are being miscounted
due to superimposed noise in the
encoder cable.
There is a backlash between the servo
motor and the machine (such as a gear
and coupling).
The rigidity of the servo motor mounting
part is low.
The output circuit is in open phase.
An unbalanced torque on machine side
is large.
The eccentricity due to a core gap is
large.
The load for the shaft of the servo motor
is large.
An external vibration propagated to the
servo motor.
Possible cause
11 - 23
Action
Reduce the auto tuning response, and
readjust the gain. (Refer to chapter 9).
Adjust the machine resonance
suppression filter. (Refer to section
10.3.)
Adjust gains. (Refer to chapter 9.)
Execute the filter adjustment.
(Refer to section 10.4.)
Take countermeasures against noise
by laying the encoder cable apart from
power cables, etc.
Adjust the backlash on the coupling
and the machine part.
Increase the rigidity of the mounting
part by methods, such as increasing
the board thickness and reinforcing the
part with ribs.
Review the wiring of servo motor
power cable.
Adjust the balance of the machine
side.
Review the direct accuracy.
Adjust the load for the shaft to within
the specifications of the servo motor.
For the shaft permissible load, refer to
Servo Motor Instruction Manual
(Vol.2).
Prevent the vibration from the external
vibration source.