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229
Problems and Countermeasures
Section 8-3
28
Motor rotation is
unstable.
The parameters are set incor-
rectly.
Check the MC Unit parameters
with Motion Perfect.
Set the parameters correctly
and modify the initialisation
program accordingly.
29
The Servo Motor power lines
and encoder lines are wired
incorrectly.
Check the Servo Motor power
lines and encoder lines.
Correct the wiring.
30
There is eccentricity in the cou-
plings connecting the Servomo-
tor axis and the mechanical
system. There may be loose
screws or load torque fluctua-
tion due to the meshing of pul-
ley gears.
Check the machinery. Try turn-
ing the motor with no load (i.e.,
with the machinery removed
from the coupling).
Adjust the machinery.
31
The gain adjustment is insuffi-
cient.
---
Execute Servomotor autotun-
ing.
Manually adjust the Servo-
motor gain.
Adjust the servo control
parameters with Motion Per-
fect.
32
The wrong Servomotor is
selected (so it cannot be
adjusted).
Check the torque and inertia
ratings and select another Ser-
vomotor.
Change to a suitable Servo-
motor.
33
The Servomotor bearings are
damaged.
Turn OFF the Servo Driver
power. If the Servomotor has a
brake, turn ON the brake power
supply and release the brake,
and then manually turn the
motor’s output axis with the
motor’s power line discon-
nected (because the dynamic
brake may be applied).
Replace the Servomotor.
34
The Servomotor windings are
disconnected.
With a tester, check resistance
between the Servomotor’s U, V
and W power lines. There
should be a proper balance
between the line resistances.
Replace the Servomotor.
35
Vibration is
occurring at the
same frequency
as the application
frequency.
Inductive noise is being gener-
ated.
Check whether the Servo Driver
control signals are too long.
Check whether the control sig-
nal lines and power lines are
bundled together.
Shorten the control signals.
Separate the control signal
lines and the power lines.
Use a low-impedance power
supply for the control signal
lines.
36
The control signals are not
properly grounded.
Check whether the control sig-
nal shield is properly grounded
at the Servo Driver.
Check whether the control sig-
nal lines are in contact with
ground.
Correct the wiring.
37
Twisted-pair or shielded cable
is not being used between the
MC Unit and other devices.
Check whether twisted-pair
cables are used for the encoder
signals and speed references,
and whether the cables are
shielded.
Use twisted-pair and shielded
cable as in the wiring exam-
ples.
No.
Problem
Probable causes
Items to check
Remedy