YASKAWA Sigma-V Series User Manual page 384

10 Troubleshooting
Problem
Abnormal Noise
from Servomotor
10-28
Probable Cause
The servomotor largely vibrated
during execution of tuning-less
function.
Mounting is not secured.
Mounting is not secured.
Bearings are defective.
Vibration source at the driven
machine.
Noise interference due to incorrect
I/O signal cable specifications.
Noise interference due to length of
I/O signal cable.
Noise interference due to incorrect
cable specifications of encoder
cable.
Noise interference due to length of
encoder cable.
Noise interference due to damaged
encoder cable.
Excessive noise to the encoder
cable.
The FG potential varies because of
influence from machines on the ser-
vomotor side, such as the welder.
SERVOPACK pulse counting error
due to noise interference
Excessive vibration and shock to
the encoder
An encoder fault occurred.
Investigative Actions
Check the motor speed waveform.
Check if there are any loose mount-
ing screws.
Check if there is misalignment of
couplings.
Check if there are unbalanced cou-
plings.
Check for noise and vibration
around the bearings.
Check for any foreign matter, dam-
age, or deformations on the machin-
ery's movable parts.
The I/O signal cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
min.
Check the length of the I/O signal
cable.
The encoder cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
min.
Check the length of the encoder
cable.
Check if the encoder cable is bent
and the sheath is damaged.
Check if the encoder cable is bun-
dled with a high-current line or near
a high-current line.
Check if the machines are correctly
grounded.
Check if there is noise interference
on the I/O signal line from the
encoder.
Check if vibration from the machine
occurred or servomotor installation
is incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
−
Corrective Actions
Reduce the load so that the moment
of inertia ratio becomes within the
allowable value, or increase the
load level or lower the tuning level
for the tuning-less levels setting
(Fn200).
Tighten the mounting screws.
Align the couplings.
Balance the couplings.
Replace the servomotor.
Contact the machine manufacturer.
Use the specified I/O signal cable.
2
The I/O signal cable length must be
no more than 3 m.
Use the specified encoder cable.
2
The encoder cable must be no more
than 50 m.
Replace the encoder cable and cor-
rect the cable layout.
• Correct the cable layout so that
no surge is applied.
• Use a double-shielded encoder
cable.
Properly ground the machines to
separate from the encoder FG.
Take measures against noise in the
encoder wiring.
Reduce vibration from the machine,
or secure the servomotor installa-
tion.
Replace the servomotor.
(cont'd)