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Digital Operator Display
Minor Fault Name
Uv
Undervoltage
One of the following conditions was true when the drive was stopped and a run command was entered:
• DC bus voltage dropped below the level specified in L2-05.
• Contactor to suppress inrush current in the drive was open.
• Low voltage in the control drive input power. This alarm outputs only if L2-01 is not 0 and DC bus
voltage is under L2-05.
Cause
Possible Solution
Minor Fault
(H2-
oo
= 10)
Phase loss in the drive input power.
Check for wiring errors in the main circuit drive input power. Correct the wiring.
YES
Loose wiring in the drive input power
terminals.
• Ensure the terminals have been properly tightened.
• Apply the tightening torque specified in this manual to fasten the terminals.
Wire Gauges and Tightening Torques on page 58
.
There is a problem with the drive input power
voltage.
• Check the voltage.
• Lower the voltage of the drive input power so that it is within the limits listed in the
specifications.
Drive internal circuitry is 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 when the power is
switched on.
• Check for a tripped alarm when the magnetic contactor, line breaker and leakage breaker
are turned on.
• Check the capacity of the drive input power transformer.
Air inside the drive is too hot.
• Check the temperature inside the drive.
The CHARGE indicator light is broken or
disconnected.
• Replace the drive.
6.5 Alarm Detection
290
YASKAWA ELECTRIC SIEP C710606 18F YASKAWA AC Drive – V1000 Technical Manual