6.4 Fault Detection
288
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
Digital Operator Display
Fault Name
UL3
Undertorque Detection 1
The current has fallen below the minimum value set for torque detection (L6-02) for longer than the allowable time (L6-03).
Cause
Possible Solution
Parameter settings are not appropriate for the load.
Check the settings of parameters L6-02 and L6-03.
There is a fault on the machine side.
Check the load for any problems.
Digital Operator Display
Fault Name
UL4
Undertorque Detection 2
The current has fallen below the minimum value set for torque detection (L6-05) for longer than the allowable time (L6-06).
Cause
Possible Solution
Parameter settings are not appropriate for the load.
Check the settings of parameters L6-05 and L6-06.
There is a fault on the machine side.
Check the load for any problems.
Digital Operator Display
Fault Name
Uv1
DC Bus Undervoltage
One of the following conditions occurred while the drive was running:
• Voltage in the DC bus fell below the undervoltage detection level (L2-05)
• For 200 V class: approximately 190 V
• For 400 V class: approximately 380 V (350 V when E1-01 is less than 400) In normal operation, the fault is output only if L2-
01 = 0 or L2-01 = 1 and the DC bus voltage has fallen below the level set to L2-05 for longer than the time set to L2-02.
During KEB deceleration, a fault is output when the DC bus voltage falls below 300 Vdc.
Cause
Possible Solution
Input power phase loss.
• The main circuit drive input power is wired incorrectly.
• Correct the wiring.
One of the drive input power wiring terminals is loose.
• Ensure there are no loose terminals.
• Apply the tightening torque specified in this manual to fasten the terminals.
Refer to Wire Gauges and Tightening Torque on
There is a problem with the voltage from the drive input
power.
• Check the voltage.
• Correct the voltage to be within the range listed in drive input power specifications.
• If there is no problem with the power supply to the main circuit, check for problems with the main circuit magnetic contactor.
The power has been interrupted.
Correct the drive input power.
The main circuit capacitors are worn.
• Check the maintenance time for the capacitors (U4-05).
• Replace either the control board or the entire drive if U4-05 exceeds 90%. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
The relay or contactor on the soft-charge bypass circuit
is damaged.
• Cycle power to the drive and see if the fault reoccurs.
• If the problem continues, replace either the control board or the entire drive. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
• Check monitor U4-06 for the performance life of the soft-charge bypass.
• Replace either the control board or the entire drive if U4-06 exceeds 90%. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
KEB deceleration was not successful.
Check the settings in parameter groups S4, S5 and S6.
Digital Operator Display
Fault Name
Uv2
Control Power Supply Voltage Fault
Voltage is too low for the control drive input power.
Cause
Possible Solution
L2-02 was changed from its default value without
installing a Momentary Power Loss Ride-Thru unit in
models CIMR-T
2A0004 to 2A0056 and CIMR-
T
4A0002 to 4A0031.
Correct the setting to L2-02 or install an optional Momentary Power Loss Ride-Thru unit.
Control power supply wiring is damaged.
• Cycle power to the drive. Check if the fault reoccurs.
• If the problem continues, replace the control board, the entire drive, or the control power supply.
Internal circuitry is damaged.
• Cycle power to the drive. Check if the fault reoccurs.
• If the problem continues, replace either the control board or the entire drive. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
Digital Operator Display
Fault Name
Uv3
Undervoltage 3 (Soft-Charge Bypass Circuit Fault)
The soft-charge bypass circuit has failed.
Cause
Possible Solution
The relay or contactor on the soft-charge bypass circuit
is damaged.
• Cycle power to the drive and see if the fault reoccurs.
• If the problem continues, replace either the control board or the entire drive. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
• Check monitor U4-06 for the performance life of the soft-charge bypass.
• Replace either the control board or the entire drive if U4-06 exceeds 90%. For instructions on replacing the control board,
contact Yaskawa or your nearest sales representative.
Digital Operator Display
Fault Name
voF
Output Voltage Detection Fault
Problem detected with the voltage on the output side of the drive.
Cause
Possible Solution
Hardware is damaged.
Replace either the control board or the entire drive. For instructions on replacing the control board, contact Yaskawa or your
nearest sales representative.
<1> Displays
or
if a control circuit error occurs while the drive is starting up.
Displays
or
if a control circuit error occurs mid-operation.
<2> This function prevents continuous operation in reverse when using high frequency injection (n8-57 = 1) in the Advanced Open Loop Vector
Control mode for PM motors (A1-02 = 6) with a motor for which no motor code has been entered (it does not simply prevent reverse
operation). To quickly detect undesirable reverse operation, set L8-93, L8-94, and L8-95 to low values within range of erroneous detection.