YASKAWA SGD7S-180A - Page 195

8.3 Troubleshooting Based on the Operation and Conditions of the Servomotor
8-55
8
Maintenance
Abnormal
Noise from
Servomotor
The bearings are defective.
Turn OFF the power sup-
ply to the servo system.
Check for noise and
vibration around the bear-
ings.
Replace the Servomo-
tor.
–
There is a vibration source at
the driven machine.
Turn OFF the power sup-
ply to the servo system.
Check for any foreign
matter, damage, or defor-
mation in the machine’s
moving parts.
Consult with the
machine manufacturer.
–
Noise interference occurred
because of incorrect I/O sig-
nal cable specifications.
Turn OFF the power sup-
ply to the servo system.
Check the I/O signal
cables to see if they sat-
isfy specifications. Use
shielded twisted-pair wire
cables or screened
twisted-pair cables with
conductors of at least
0.12 mm
2
.
Use cables that satisfy
the specifications.
–
Noise interference occurred
because an I/O signal cable
is too long.
Turn OFF the power sup-
ply to the servo system.
Check the lengths of the
I/O signal cables.
The I/O signal cables
must be no longer than
3 m.
–
Noise interference occurred
because of incorrect Encoder
Cable specifications.
Turn OFF the power sup-
ply to the servo system.
Make sure that the rotary
or Linear Encoder Cable
satisfies the specifica-
tions. Use a shielded
twisted-pair wire cable or
a screened twisted-pair
cable with a conductors
of at least 0.12 mm
2
.
Use cables that satisfy
the specifications.
–
Noise interference occurred
because the Encoder Cable
is too long.
Turn OFF the power sup-
ply to the servo system.
Check the length of the
Encoder Cable.
• Rotary Servomotors:
The Encoder Cable
length must be 50 m
max.
• Linear Servomotors:
Make sure that the
Serial Converter Unit
cable is no longer
than 20 m and that
the Linear Encoder
Cable and the Sensor
Cable are no longer
than 15 m each.
–
Noise interference occurred
because the Encoder Cable
is damaged.
Turn OFF the power sup-
ply to the servo system.
Check the Encoder Cable
to see if it is pinched or
the sheath is damaged.
Replace the Encoder
Cable and correct the
cable installation envi-
ronment.
–
The Encoder Cable was sub-
jected to excessive noise
interference.
Turn OFF the power sup-
ply to the servo system.
Check to see if the
Encoder Cable is bundled
with a high-current line or
installed near a high-cur-
rent line.
Correct the cable lay-
out so that no surge is
applied by high-current
lines.
–
Continued on next page.
Continued from previous page.
Problem Possible Cause Confirmation Correction Reference