Yaskawa Z1000U HVAC Matrix Bypass - Manual (Page 250)

HOA Keypad 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
conditions for mechanical loss detection set to
L6-08
Check the load side for any problems.
HOA Keypad Display Fault Name
Uv1
Control Circuit Undervoltage Fault
Voltage in the control circuit fell below the detection level:
• For 200 V class drives: approximately 175 V
• For 400 V class drives: approximately 350 V
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 Gauge
and Tightening Torque Specifications on page 86 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
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 a Yaskawa 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 a Yaskawa representative.
HOA Keypad Display Fault Name
Uv2
Control Power Supply Voltage Fault
Voltage is too low for the control drive input power.
Cause Possible Solution
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 a Yaskawa representative.
HOA Keypad Display Fault Name
Uv3
Undervoltage 3 (Soft-Charge Bypass Relay Fault)
The soft-charge bypass relay failed.
Cause Possible Solution
The relay or contactor on the soft-charge bypass
circuit is damaged
• Cycle power to the drive.
• If the problem continues, replace the entire drive. Contact Yaskawa or your nearest sales
representative.
• Check monitor U4-06 for the performance life of the soft-charge bypass.
• Replace the entire drive if U4-06 exceeds 90%. Contact Yaskawa or your nearest sales
representative.
6.4 Fault Detection
250 YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual