Troubleshooting
7
7.4 Fault
YASKAWA SIEPYEULA5001C LA500 Technical Manual 177
Code Name Causes Possible Solutions
An increase in the stray capacitance of the cable and
the ground terminal caused an increase in the
leakage current.
• If the wiring length of the cable is more than 100 m, decrease
the carrier frequency.
• Decrease the stray capacitance.
There was a problem with the drive hardware. Replace the control board or the drive. For information about
replacing the control board, contact Yaskawa or your nearest sales
representative.
Note:
• The drive detects this fault if a current short to ground was more than 50% of rated current on the output side of the drive.
• Do a Fault Reset to clear the fault.
• L5-08 [Fault Reset Enable Select Grp2] disables the Auto Restart function.
Code Name Causes Possible Solutions
LF Output Phase Loss
The motor main circuit cable is disconnected. Connect motor main circuit cable wiring. Correct wiring errors in
the main circuit drive input power.
There is a disconnection in the motor coil winding. If a coil is disconnected, measure the motor Line-to-Line
Resistance and replace the motor.
The screws on the drive output terminals are loose. Tighten the terminal screws to the correct tightening torque.
The rated output current of the motor is less than
5% of the drive rated current.
Examine the drive capacity or the motor output to be applied.
You are trying to use a single-phase motor. The drive cannot operate a single-phase motor.
The output transistor in the drive is damaged. • Re-energize the drive.
• If the fault stays, replace the control board or the drive. For
information about replacing the control board, contact
Yaskawa or your nearest sales representative.
Note:
• The drive detects this fault if phase loss occurs on the output side of the drive.
• Do a Fault Reset to clear the fault.
• Set L8-07 [Output Phase Loss Protection Sel] to enable and disable LF detection.
Code Name Causes Possible Solutions
LF2 Output Current Imbalance
Phase loss occurred in the wiring on the output side
of the drive.
Examine for wiring errors or disconnected wires on the output
side of the drive, and repair problems.
The output terminal screws of the drive are loose. Tighten the terminal screws to the correct tightening torque.
There is not balance between the three phases of the
PM motor impedance.
• Measure the Line-to-Line Resistance for each motor phase and
make sure that resistance is equal in the three phases, and that
all wires are connected correctly.
• Replace the motor.
The drive output circuit is broken. • Re-energize the drive.
• If the fault stays, replace the control board or the drive. For
information about replacing the control board, contact
Yaskawa or your nearest sales representative.
Note:
• The drive detects this fault if there is not balance between the three phases of the output current from the PM motor.
• Do a Fault Reset to clear the fault.
Code Name Causes Possible Solutions
oC Overcurrent
The load is too heavy. • Measure the current flowing into the motor.
• Replace the drive with a larger capacity model if the current
value is more than the drive rated current.
• Decrease the load or replace with a larger drive to prevent
sudden changes in the current level.
Overheating caused damage to the motor or the
motor insulation is not satisfactory.
Measure the motor insulation resistance, and replace the motor if
there is electrical conduction or unserviceable insulation.
The motor main circuit cable is contacting ground
to make a short circuit.
• Examine the motor main circuit cable for damage, and repair
short circuits.
• Measure the resistance between the motor main circuit cable
and the ground terminal. If there is electrical conduction,
replace the cable.
A short circuit or ground fault on the drive output
side caused damage to the output transistor of the
drive.
• Make sure that there is not a short circuit in terminal B1 and
terminals U/T1, V/T2, and W/T3. Make sure that there is not a
short circuit in terminals - and terminals U/T1, V/T2, and W/
T3.
• If there is a short circuit, contact Yaskawa or your nearest sales
representative.
The acceleration time is too short. • Calculate the torque necessary during acceleration related to
the load inertia and the specified acceleration time.
• Increase the values set in C1-01, C1-03, C1-05, or C1-07
[Acceleration Times] to get the necessary torque.
• Increase the values set in C2-01 to C2-04 [S-Curve
Characteristics] to get the necessary torque.
• Replace the drive with a larger capacity model.