YASKAWA E-V Series User Manual page 234

8 Troubleshooting
Problem
Position error
(without alarm)
Servomotor
Overheated
8-30
Probable Cause
Noise interference due to improper
I/O signal cable specifications
Noise interference because the I/O
signal cable distance is too long.
Reference frequency is too high.
Serial converter unit fault (pulse
count does not change)
Surrounding air temperature is too
high.
Servomotor surface is dirty.
Overloaded
Polarity detection is not performed
correctly.
Investigative Actions
The input signal cable specifica-
tions must be:
Twisted-pair or twisted-pair
shielded wire with core
2
0.12 mm min. and tinned annealed
copper twisted wire.
The wiring distance must be 3 m
max. and the impedance several
hundreds ohm max.
Check Un00C (Input Reference
Counter.)
−
Measure the servomotor surround-
ing air temperature.
Check visually.
Run under no load.
Check if the value of Un004 (Elec-
trical Angle 2, angle from 0 (zero)
degree of phase-U) at an arbitrary
position is between ±10 degrees.
Corrective Actions
Use I/O signal cable with the speci-
fied specifications.
The I/O signal cable distance must
be within the specified range.
Reduce the reference frequency to a
value within the specification.
Replace the serial converter unit.
Reduce the surrounding air temper-
ature to 40°C max.
Clean dust and oil from servomotor
surface.
Reconsider load and operation con-
ditions or replace with larger capac-
ity servomotor.
Correct the settings for the polarity
detection related parameter.