YASKAWA FSDrive-MV1000 Instructions Manual page 138

5.5 Alarm Detection
Digital Operator Display
Uv
Cause
Phase loss in the drive input power.
Loose wiring in the drive input power
terminals.
There is a problem with the drive input power
voltage.
The power has been interrupted.
Digital Operator Display
VUB
Cause
The motor has been damaged due to
overheating or the motor insulation is
damaged.
One of the motor cables has shorted out or
there is a grounding problem.
The output side cable wiring is wrong.
138
Undervoltage
One of the following conditions was true while the drive was stopped (a Run command was
not entered):
• DC bus voltage dropped below the level specified in L2-05.
• Contactor to suppress inrush current in the drive was opened.
• Low voltage in the control drive input power.
Possible Solutions
Check for wiring errors in the main circuit drive input power.
⇒Correct the wiring.
Ensure the terminals have been properly tightened.
⇒Retighten the terminals to the tightening torques specified in this
manual (refer to page 64).
⇒Lower the voltage of the drive input power so that it is within the
limits listed in the specifications.
⇒Correct the drive input power.
Voltage Unbalance
The sum of the detected output voltages of the three phases exceeded the detection level for
longer than the stipulated time.
Possible Solutions
Check the insulation resistance of the motor.
⇒Replace the motor.
Check the motor cable.
⇒Remove the short circuit and turn the power back on.
Check the resistance between the motor cables and the ground
terminal .
⇒Replace the cable.
⇒Correct the wiring.
Minor Fault Name
Minor Fault Name
YASKAWA ELECTRIC EZZ010928 FSDrive-MV1000 Instructions
Minor Fault
Output
H2- =10
Yes
Minor Fault
Output
H2- =10
Yes