Mitsubishi Electric MELSERVO-J3W Series Instruction Manual page 165

8. TROUBLESHOOTING
Alarm No.52
Alarm description
Display Name
52.3 Excess droop
pulse
52.4 Maximum
deviation at 0
torque limit
Name: Error excessive
The droop pulses existing between the model position and the actual servo motor position exceeds the
alarm level.
Cause
(1) Power cable is cut.
(2) Misconnection of the
servo motor.
(3) Misconnection of encoder
cable.
(4) Torque limit value is too
small.
(5) Machine struck
something.
(6) Torque shortage.
(7) Equipment cannot be
started because of torque
shortage caused by the
power supply voltage
drop.
(8) Acceleration/deceleration
time constant is too
small.
(9) Position loop gain is too
small.
(10) Servo motor shaft is
rotated by external force.
(11) Encoder is faulty.
(1) Torque limit is set to 0.
Stop method: Corresponding axis stops
Checkpoint
Check the power cable. No connection (open
phase).
No problem found.
Check the connection of Misconnection found.
U, V and W phases.
Misconnection not
found.
Check the axis where Misconnection found.
encoder cable is
Misconnection not
connected.
found.
Check the torque limit Torque limit value is
value. small.
Within the setting
range.
Check if the machine Struck.
struck something.
Did not strike.
Check if the torque is Torque is saturated.
saturated.
Torque is not
saturated.
Check the bus voltage Bus voltage is low.
using MR Configurator .
Bus voltage is high.
Set acceleration/ Not reproduced.
deceleration time longer,
and check the
Reproduced.
reproducibility of the error.
Change the position loop Not reproduced.
gain, and check the
reproducibility of the error. Reproduced.
Measure the actual servo Motor moves.
motor position in the
Does not move.
servo lock status.
Replace the servo motor Alarm does not occur.
and check the
reproducibility of the error.
Check the torque limit Torque limit is 0.
value.
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Finding Action
Modify the wiring.
Check (2).
Modify the wiring.
Check (3).
Modify the wiring.
Check (4).
Increase the torque
limit value.
Check (5).
Review the operation
pattern.
Check (6).
Reduce load.
Check operation
pattern.
Use servo motor that
provides larger output.
Check (7).
Review the power
supply voltage.
Check (8).
Review the operation
pattern.
Check (9).
Review the position
loop gain.
Check (10).
Check the machine.
Check (11).
Replace the servo
motor.
Increase the torque
limit value.