HOA Keypad 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 Wire Gauges and
Tightening Torque on page 87 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
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
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. For
instructions on replacing the control board, contact Yaskawa or a Yaskawa representative.
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 Circuit Fault)
The soft-charge bypass circuit 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 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
VLTS Volute-Thermostat Fault
Cause Possible Solution
5.2 Fault Detection
YASKAWA TOEP YAIP1W 01A YASKAWA AC Drive - iQpump1000 Quick Start Guide
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Troubleshooting