YASKAWA JUSP-MD D01A Series User Manual page 315

9 Troubleshooting
Problem
Servomotor
Moves
Instantaneously,
and then Stops
Servomotor
Speed Unstable
Servomotor
Rotates Without
Reference Input
Dynamic Brake
Does Not Operate
Abnormal Noise
from Servomotor
9-26
Probable Cause
Servomotor wiring is incorrect.
Encoder wiring is incorrect.
Wiring connection to servomotor is
defective.
Speed control: Speed reference
input is incorrect.
Torque control: Torque reference
input is incorrect.
Speed reference offset is incorrect.
Position control: Reference pulse
input is incorrect.
A fault occurred in the multi-wind-
ing drive unit.
Improper Pn001.0 setting
DB resistor disconnected
DB drive circuit fault
Wiring of the dynamic brake unit is
incorrect.
The servomotor largely vibrated
during execution of tuning-less
function.
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.
Investigative Actions
Check the wiring.
Check the wiring.
Check connections of power line
(phases U, V, and W) and encoder
connectors.
Check V-REF and SG to confirm if
the control method and the input are
agreed.
Check V-REF and SG to confirm if
the control method and the input are
agreed.
The offset in the multi-winding
drive unit is adjusted incorrectly.
Check the reference pulse form
(Pn200.0) and sign + pulse signal.
−
Check the setting for parameter
Pn001.0.
Check if excessive moment of iner-
tia, motor overspeed, or DB fre-
quently activated occurred.
−
Check the wiring.
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.
Corrective Actions
Correct the wiring.
Correct the wiring.
Tighten any loose terminals or con-
nectors and correct the wiring.
Correct the control method selec-
tion parameter, and the input signal.
Correct the control method selec-
tion parameter, and the input signal.
Adjust the offset in the multi-wind-
ing drive unit.
Correct the control method selec-
tion parameter, and the input signal.
Replace the multi-winding drive
unit.
Correct the setting for parameter
Pn001.0.
Replace the dynamic brake unit or
change the external dynamic brake
circuit. And reduce the load.
A defective component is in the
dynamic brake circuit inside SER-
VOPACK. Replace the SERVO-
PACK.
Correct the wiring.
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.
(cont'd)