Mitsubishi Electric MELSERVO-J2 Series Instruction Manual page 208

11. TROUBLESHOOTING
Display
A.50 Overload 1
A.51 Overload 2
A.52 Error excessive
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Name Definition
Load exceeded
overload protection
characteristic of
servo amplifier.
Load ratio 300%:
2.5s or more
Load ratio 200%:
100s or more
Machine collision or
the like caused max.
output current to
flow successively for
several seconds.
Servo motor locked:
1s or more
Droop pulse value of
the deviation counter
exceeded 80k pulses.
search engine
Cause
5. Encoder faulty.
Checking method
When the servo motor shaft is
rotated with the servo off, the
cumulative feedback pulses do
not vary in proportion to the
rotary angle of the shaft but the
indication skips or returns midway.
1. Machine struck something.
2. Wrong connection of servo motor.
Servo amplifier's output terminals U,
V, W do not match servo motor's input
terminals U, V, W.
3. Servo system is instable and hunting.
4. Encoder faulty.
Checking method
When the servo motor shaft is
rotated with the servo off, the
cumulative feedback pulses do
not vary in proportion to the
rotary angle of the shaft but the
indication skips or returns midway.
1. Acceleration/deceleration time constant
is too small.
2. Torque limit value (parameter No.28)
is too small.
3. Motor cannot be started due to torque
shortage caused by power supply
voltage drop.
4. Position control gain 1 (parameter
No.7) value is small.
5. Servo motor shaft was rotated by
external force.
6. Machine struck something.
7. Encoder faulty
8. Wrong connection of servo motor.
Servo amplifier's output terminals U,
V, W do not match servo motor's input
terminals U, V, W.
11 - 7
Action
Change the servo motor.
1. Review operation pattern.
2. Install limit switches.
Connect correctly.
1. Repeat acceleration/
deceleration to execute auto
tuning.
2. Change auto tuning response
level setting.
3. Set auto tuning to OFF and
make gain adjustment
manually.
Change the servo motor.
Increase the
acceleration/deceleration time
constant.
Increase the torque limit value.
1. Review the power supply
capacity.
2. Use servo motor which
provides larger output.
Increase set value and adjust to
ensure proper operation.
1. When torque is limited,
increase the limit value.
2. Reduce load.
3. Use servo motor that provides
larger output.
1. Review operation pattern.
2. Install limit switches.
Change the servo motor.
Connect correctly.