Yaskawa AC Drive-P1000 Industrial Fan - Manual (Page 309)

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 L6-05 and L6-06 settings
There is a fault on the machine side Check the load for any problems.
Digital Operator Display Fault Name
UL6 UL6
Motor Underload
The weight of the load has fallen below the underload curve defined in L6-14.
Cause Possible Solution
The output current has fallen below the motor
underload curve defined in L6-14 for longer
than the time set to L6-03
Adjust the value set to L6-14 so that output current remains above the motor underload curve during
normal operation.
Digital Operator Display Fault Name
<1>
UnbC
Current Unbalance
Current flow has become unbalanced.
Cause Possible Solution
The internal current sensor has detected a
current unbalance situation.
• Check wiring
• Check for damaged transistors.
• Check for short circuits or grounding problems on the connected motor.
<1> Detected in models 4A0930 and 4A1200.
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 drives: approximately 190 V
• For 400 V class drives: approximately 380 V (350 V when E1-01 is less than 400)
• For 600 V class drives: approximately 475 V
The fault is output only if L2-01 is set to 0 or 1 and the DC bus voltage has fallen below the level set to
L2-05 for longer than the time set to L2-02.
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 Main Circuit
Wire Gauges and Tightening Torque on page 85 for details.
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 a Yaskawa representative.
The relay or contactor on the soft-charge
bypass relay is damaged
• Cycle power to the drive and see if the fault reoccurs.
• Check monitor U4-06 for the performance life of the soft-charge bypass relay.
• Replace either the control board or the entire drive if U4-06 exceeds 90%. For instructions on replacing
the control board, contact Yaskawa or a Yaskawa representative.
Digital Operator Display Fault Name
Uv2
Control Power Supply Voltage Fault
Voltage is too low for the control drive input power.
6.4 Fault Detection
YASKAWA SIEP YAIP1U 01B AC Drive - P1000 Technical Manual 309
6
Troubleshooting