YASKAWA Sigma-V Series User Manual page 278

Problem Probable Cause
Improper Pn001.0 setting
DB resistor disconnected
Dynamic Brake
Does Not Operate
DB drive circuit fault
Wiring of the dynamic brake unit is
incorrect.
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
Abnormal Noise
I/O signal cable.
from Servomotor
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.
Multi-winding drive unit pulse
counting error occurred due to noise
interference
8.4 Troubleshooting Malfunction Based on Operation and Conditions of the Servomotor
Investigative Actions
Check the setting for parameter
Pn001.0.
Check if excessive moment of iner-
tia, motor overspeed, or DB fre-
quently activated occurred.
−
Turn OFF the servo system.
Check the wiring.
Turn OFF the servo system. Check
if there are any loose mounting
screws.
Turn OFF the servo system. Check
if there is misalignment of cou-
plings.
Turn OFF the servo system. Check
if there are unbalanced couplings.
Turn OFF the servo system. Check
for noise and vibration around the
bearings.
Turn OFF the servo system. Check
for any foreign matter, damage, or
deformations on the machinery's
movable parts.
Turn OFF the servo system. 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.
Turn OFF the servo system. Check
the length of the I/O signal cable.
Turn OFF the servo system. 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.
Turn OFF the servo system. Check
the length of the encoder cable.
Turn OFF the servo system. Check
if the encoder cable is bent and the
sheath is damaged.
Turn OFF the servo system. Check
if the encoder cable is bundled with
a high-current line or near a high-
current line.
Turn OFF the servo system. Check
if the machines are correctly
grounded.
Check if there is noise interference
on the I/O signal line from the
encoder.
Corrective Actions
Correct the setting for parameter
Pn001.0.
Turn OFF the servo system.
Replace the dynamic brake unit or
change the external dynamic brake
circuit. And reduce the load.
Turn OFF the servo system. A
defective component is in the
dynamic brake circuit inside SER-
VOPACK. Replace the SERVO-
PACK.
Correct the wiring.
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.
Turn OFF the servo system. Take
measures against noise in the
encoder wiring.
(cont'd)
8
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