
2.EXPLANATION OF OPERATION MODES FANUC AC SPINDLE MOTOR αi series B-65280EN/05
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(iii) When the motor vibrates and makes an abnormal sound when rotating
(1) Check the feedback signal.
(a) Feedback signal level (Refer to Maintenance Manual.)
(b) Shielding and grounding (Refer to Descriptions.)
(2) Check the parameter settings.
The velocity loop gain may be too large. Adjust the following
parameters:
15i 16i 30i
Description Setting data
3040 4040 4040
Velocity loop proportional gain
(HIGH)
3041 4041 4041
Velocity loop proportional gain
(LOW)
3048 4048 4048
Velocity loop integral gain
(HIGH)
3049 4049 4049
Velocity loop integral gain
(LOW)
Decrease the setting
values.
(3) Make a comparison with the case of motor coasting.
If vibration and sound produced when the motor coasts are
extremely smaller than those produced when the motor is driven,
the control circuit is faulty. If sound produced remains
unchanged, the motor or the machine may be faulty. If the
feedback signal cable from the motor is disconnected during
motor rotation, an alarm is issued, and the motor coasts. Before
performing the coasting of the motor, consult with the machine
tool builder for confirmation. Depending on the sequence, the
brake may be applied.
(iv) When an overshoot or hunting occurs
(1) Check the parameter settings.
(a) The velocity loop gain may be too large. Adjust the
following parameters:
15i 16i 30i
Description Setting data
3040 4040 4040
Velocity loop proportional gain
(HIGH)
3041 4041 4041
Velocity loop proportional gain
(LOW)
3048 4048 4048
Velocity loop integral gain
(HIGH)
3049 4049 4049
Velocity loop integral gain
(LOW)
Decrease the setting
values.