LS ELECTRIC L7NHF Series, User Manual

Page: 368 / 409

12. Maintenance and Inspection
12-4
12.2
Diagnosing Abnormalities and Troubleshooting
An alarm or warning is generated if a problem occurs during operation. If this happens, find the
applicable code and take a proper action. If the problem persists after taking such a measure, contact
our service center.
12.2.1
Servo Motor
[Cause of abnormalities, inspection procedure, and troubleshooting methods]
Symptoms Cause Inspection Method Remedies
The motor
does not
move.
The P-OT and N-OT inputs are
off. Refer to "2. Wiring and Connection" or
"2.5. Wiring for Input/Output Signals."
Turn on the P-OT and N-OT inputs.
The motor is defective.
Use a resistance tester to measure the
resistance to the motor lead terminal
(resistance between phases: several
ohms).
Replace the motor.
The locking screws are loose. Check the locking screws. Tighten any loose screws.
The external wiring is incorrect or
the cables are disconnected. Check the wires to the motor and the
encoder.
Redo the wiring.
Replace the cables.
Encoder failure Check the output waves.
Replace the encoder.
(Contact our service center.)
Motor
rotation is
unstable.
The connection is bad.
Check the connection of the motor lead
terminal.
Fix any bad connections.
The input voltage is low. Check the input voltage of the drive. Change the power source.
Overloads occur. Check the condition of the machine.
Remove any foreign substances from the
rotating unit and grease or lubricate it.
The motor
overheats.
The ambient temperature is too
high.
Check the temperature around the motor.
(40
℃
or lower)
Change heat transfer structure.
Install a cooling fan.
The surface of the motor is
contaminated. Check whether there are any foreign
substances on the surface of the motor.
Clean the surface of the motor.
Overloads occur.
Check the load on the drive.
Check the acceleration/deceleration
time.
Reduce the load.
Increase the acceleration/deceleration
time.
Replace with a motor with a greater
capacity.
The magnetic power of the
magnets is reduced. Check the counter voltage and voltage
waveforms.
Replace the motor.
The device is
making a
strange
sound.
Coupling is bad.
Tighten the coupling screws and
measure the concentricity of the
connection.
Readjust the coupling.
The bearings are abnormal.
Check the bearings for vibrations and
sounds.
Contact us.
The parameters are set
incorrectly
(the inertia, gain, and time
constants).
Check the parameters. Refer to Chapter 9 Object Dictionary.