Yaskawa AC Drive Z1000 Bypass Technical Manual User Manual
Page 237
There is a fault on the machine side
Check the load for any problems.
HOA Keypad Display
Fault Name
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.
HOA Keypad Display
Fault Name
Uv1
DC Bus Undervoltage
Voltage in the DC bus fell below the undervoltage detection level (L2-05).
• For 208 V: approximately 190 V
• For 480 V: approximately 440 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
<1>
.
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.
and Tightening Torque Specifications on page 62
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.
<1> Details on this function can be found in the standard Z1000 Programming Manual (SIEPC71061645) at www.yaskawa.com.
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 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.
6.4 Fault Detection
YASKAWA ELECTRIC SIEP YAIZ1B 01D YASKAWA AC Drive – Z1000 Bypass Technical Manual
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Diagnostics & Troubleshooting