Yaskawa J1000 Compact Vector Control Drive - Manual (Page 151)

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 type of 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
UL5
Mechanical Weakening Detection 2
The operation conditions matched the conditions set to L6-08.
Cause Possible Solution
Undertorque was detected and
matched the condition of
mechanical loss detection
operation selection (L6-08).
Check the load side for any problems.
Digital Operator Display Fault Name
Uv1
DC Bus Undervoltage
One of the following conditions occurred while the drive was in operation:
• Voltage in the DC bus fell below the undervoltage detection level (L2-05).
• For 200 V class: approximately 190 V (160 V for single phase drives)
• For 400 V class: approximately 380 V (350 V when E1-01 is less than 400)
The fault is output only if L2-01 = 0 or L2-01 = 1 and the DC bus voltage is
under L2-05 for longer than 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 Wire Gauges and Tightening Torques on page 61 for details.
There is a problem with the voltage
from the drive input power.
• Check the voltage.
• Correct the voltage to within range listed in drive input power specifications.
The power has been interrupted. Correct the drive input power.
Drive internal circuitry has become
worn.
• Check the maintenance time for the capacitors (U4-05).
• Replace the drive if U4-05 exceeds 90%.
The drive input power transformer
is not large enough and voltage
drops after switching on power.
Check the capacity of the drive input power transformer.
Air inside the drive is too hot. Check the drive internal temperature.
5.2 Fault Detection
YASKAWA ELECTRIC TOEP C710606 47C YASKAWA AC Drive – V1000 Quick Start Guide 151
5
Troubleshooting