Troubleshooting
7
7.5 Minor Faults/Alarms
SIEPYEUOQ2A01A AC Drive Q2A Technical Manual 283
Code Name Causes Possible Solutions
UL5 Mechanical Weakening Detection 2
The drive detected undertorque as specified by the
conditions for mechanical weakening detection set
in L6-08 [MechF Enable].
Examine the machine for deterioration.
Note:
• If the drive detects this error, the terminal assigned to H2-01, H2-02, and H2-03 = 4 [2NO-2CM Func Selection, 3NO-3CM Func Selection, and 4NO-4CM Funct Selection =
Alarm] will be ON.
• If the drive detects this error, it will operate the motor as specified by the Stopping Method set in L6-08.
Code Name Causes Possible Solutions
Uv Undervoltage
The drive input power voltage is changing too
much.
• Examine the input power for problems.
• Make the drive input power stable.
• If the input power supply is good, examine the magnetic
contactor on the main circuit side for problems.
There is a phase loss in the drive input power. Correct errors with the wiring for main circuit drive input power.
There is loose wiring in the drive input power
terminals.
Tighten the terminal screws to the correct tightening torque.
There was a loss of power. Use a better power supply.
The main circuit capacitors have become
unserviceable.
Examine the capacitor maintenance time in monitor U4-05
[Capacitor Maintenance]. If U4-05 is more than 90%, replace the
control board or the drive. For information about replacing the
control board, contact the manufacturer or your nearest sales
representative.
The drive input power transformer is too small and
voltage drops when the power is switched on.
• Check for an alarm when a molded-case circuit breaker,
Leakage Breaker (ELCB, GFCI, or RCM/RCD) (with
overcurrent protective function), or magnetic contactor is ON.
• Check the capacity of the drive power supply transformer.
Air inside the drive is too hot. Check the ambient temperature of the drive.
The Charge LED is broken. Replace the control board or the entire drive. For information
about replacing the control board, contact the manufacturer or
your nearest sales representative.
Note:
• The drive detects this error if one of these conditions is correct when the Run command has not been input (while the drive is stopped).
–The DC bus voltage < L2-05 [UV Detection Lvl (Uv1)].
–The Contactor that prevents inrush current in the drive was opened.
–There is low voltage in the control drive input power.
• If the drive detects this error, the terminal assigned to H2-01, H2-02, and H2-03 = 4 [2NO-2CM Func Selection, 3NO-3CM Func Selection, and 4NO-4CM Funct Selection =
Alarm] will be ON.