YASKAWA Sigma-7 Series Product Manual page 136

6.3 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Servomotor
Moves with-
out a Refer-
ence Input
Dynamic
Brake Does
Not Operate
Abnormal
Noise from
Servomotor
6-48
Possible Cause
A failure occurred in the
SERVOPACK.
The count-up direction of the
linear encoder does not
match the forward direction
of the Moving Coil in the
motor.
Polarity detection was not
performed correctly.
The setting of Pn001 =
n.X (Motor Stopping
Method for Servo OFF and
Group 1 Alarms) is not suit-
able.
The dynamic brake resistor is
disconnected.
There was a failure in the
dynamic brake drive circuit.
The Servomotor vibrated
considerably while perform-
ing the tuning-less function
with the default settings.
The machine mounting is not
secure.
Confirmation
–
Check the directions.
Check to see if electrical
angle 2 (electrical angle
from polarity origin) at any
position is between ±10°.
Check the setting of
Pn001 = n.X.
Check the moment of
inertia, motor speed, and
dynamic brake frequency
of use. If the moment of
inertia, motor speed, or
dynamic brake frequency
of use is excessive, the
dynamic brake resis-
tance may be discon-
nected.
–
Check the waveform of
the motor speed.
Turn OFF the power sup-
ply to the servo system.
Check to see if there are
any loose mounting
screws.
Continued from previous page.
Correction Reference
Turn OFF the power
supply to the servo
system.
–
Replace the SERVO-
PACK.
Change the setting of
Pn080 = n.X
(Motor Phase
*
Sequence Selection).
Match the linear
encoder direction and
Servomotor direction.
Correct the settings for
the polarity detection-
–
related parameters.
Set Pn001 = n.X
–
correctly.
Turn OFF the power
supply to the servo
system.
Replace the SERVO-
–
PACK. To prevent dis-
connection, reduce the
load.
There is a defective
component in the
dynamic brake circuit.
Turn OFF the power
–
supply to the servo
system.
Replace the SERVO-
PACK.
Reduce the load so
that the moment of
inertia ratio or mass
ratio is within the allow-
able value, or increase
the load level or reduce
the rigidity level in the
tuning-less level set-
*
tings.
If the situation is not
improved, disable the
tuning-less function
(i.e., set Pn170 to
n.0) and execute
autotuning either with
or without a host refer-
ence.
Tighten the mounting
–
screws.
Continued on next page.