YASKAWA UAK series, User Manual

Page: 297 / 340

11.5 Troubleshooting Malfunction Based on Operation and Conditions of the Motor
11-43
Inspection, Maintenance, and
Troubleshooting
1 1
Abnormal Noise
from Servomotor
Mounting is not secured.
Check if there are any loose mount-
ing screws.
Tighten the mounting screws.
Check if there is misalignment of
couplings.
Align the couplings.
Check if there are unbalanced cou-
plings.
Balance the couplings.
Bearings are defective.
Check for noise and vibration
around the bearings.
Replace the motor.
Vibration source at the driven
machine
Check for any foreign matter, dam-
age, or deformations on the machin-
ery's movable parts.
Contact the machine manufacturer.
Noise interference due to incorrect
I/O signal cable specifications
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
2
min.
Use the specified I/O signal cable.
Noise interference due to length of
I/O signal cable Check the length of the I/O signal
cable. The I/O signal cable length must be
no more than 3 m.
Noise interference due to incorrect
encoder cable specifications
The encoder cable must be tinned
annealed copper shielded twisted-
pair or screened unshielded twisted-
pair cable with a core of 0.12 mm
2
min.
Use the specified encoder cable.
Noise interference due to length of
encoder cable Check the length of the encoder
cable. The encoder cable must be no more
than 20 m.
Noise interference due to damaged
encoder cable Check if the encoder cable is bent
and the sheath is damaged. Replace the encoder cable and mod-
ify the encoder cable layout.
Excessive noise to the encoder
cable
Check if the encoder cable is bun-
dled with a high-current line or near
a high-current line.
Correct the encoder cable layout so
that no surge is applied.
The FG potential varies because of
influence from machines on the ser-
vomotor side, such as the welder.
Check if the machines are correctly
grounded. Properly ground the machines to
separate from the encoder FG.
SERVOPACK pulse counting error
due to noise interference
Check if there is noise interference
on the I/O signal line from the
encoder.
Take measures against noise in the
encoder wiring.
Excessive vibration and shock to
the encoder
Check if vibration from the machine
occurred or motor installation is
incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
Reduce vibration from the machine,
or secure the motor installation.
Encoder failure
−
Replace the motor.
Motor Vibrates at
Frequency of
Approx. 200 to
400 Hz.
Unbalanced servo gains
Check to see if the servo gains have
been correctly adjusted.
Execute the advanced autotuning.
Speed loop gain value (Pn100) too
high Check the speed loop gain (Pn100).
Factory setting: Kv = 40.0 Hz Reduce the speed loop gain
(Pn100).
Position loop gain value (Pn102)
too high
Check the position loop gain
(Pn102).
Factory setting: Kp = 40.0/s
Reduce the position loop gain
(Pn102).
Incorrect speed loop integral time
constant (Pn101)
Check the speed loop integral time
constant (Pn101).
Factory setting: Ti = 20.0 ms
Correct the speed loop integral time
constant (Pn101).
Incorrect moment of inertia ratio
(Pn103) Check the moment of inertia ratio
(Pn103). Correct the moment of inertia ratio
(Pn103).
(cont’d)
Problem Probable Cause Investigative Actions Corrective Actions