YASKAWA P1000 Quick Start Manual page 144

5.2 Fault Detection
Cause
Parameter settings are not appropriate for the
load
There is a fault on the machine side
Digital Operator Display
UL6
Cause
The output current has fallen below the motor
underload curve defined in L6-14 for longer
than the time set to L6-03
<1>
<1> Detected in models 4A0930 and 4A1200.
Cause
Input power phase loss
One of the drive input power wiring terminals
is loose
There is a problem with the voltage from the
drive input power
The power has been interrupted
The main circuit capacitors are worn
The relay or contactor on the soft-charge
bypass relay is damaged
Digital Operator Display
Cause
In drive models 2A0004 to 2A0056 or 4A0002
to 4A0031, L2-02 was changed from its
default value without installing a Momentary
Power Loss Ride-Thru unit
144
Undertorque Detection 1
UL3
The current has fallen below the minimum value set for torque detection (L6-02) for longer than the
allowable time (L6-03).
Check the settings of parameters L6-02 and L6-03.
Check the load for any problems.
Undertorque Detection 2
UL4
The current has fallen below the minimum value set for torque detection (L6-05) for longer than the
allowable time (L6-06).
Motor Underload
UL6
The weight of the load has fallen below the underload curve defined in L6-14.
Adjust the value set to L6-14 so that output current remains above the motor underload curve during
normal operation.
Current Unbalance
UnbC
Current flow has become unbalanced.
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
Uv1
• 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.
• The main circuit drive input power is wired incorrectly.
• Correct the wiring.
• Ensure there are no loose terminals.
• Apply the tightening torque specified in this manual to fasten the terminals.
Wire Gauges and Tightening Torque on page 57
• 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.
Correct the drive input power.
• 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.
• 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.
Control Power Supply Voltage Fault
Uv2
Voltage is too low for the control drive input power.
Correct the setting to L2-02 or install an optional Momentary Power Loss Ride-Thru unit.
Possible Solution
Fault Name
Possible Solution
Possible Solution
Fault Name
Possible Solution
YASKAWA ELECTRIC TOEP YAIP1U 01B YASKAWA AC Drive - P1000 Quick Start Guide
Refer to Main Circuit
for details.