
8. Fault Diagnosis
171
Protective
Operation
Output is
turned OFF
and motor
coasts to a
stop.
OV (Main circuit
overvoltage)
Main circuit DC voltage level
exceeded the overvoltage de-
tection level while the Inverter
was running.
Detection level (DC voltage:
Voltage between terminals
"+1" and "-")
200 V: Approx. 410 V or more
400 V: Approx. 820 V or more
1. Regenerative energy is
large.
• The setting of decelera-
tion time is too short.
• Negative load (e.g., ele-
vator) is excessive at
lowering.
• Confirm that the load
does not have any prob-
lem.
2. Input voltage is errone-
ous.
Confirm that DC voltage
exceeding the left value
is not input.
UV1 (Main circuit low
voltage)
Main circuit DC voltage
dropped below the low-volt-
age detection level while the
Inverter output is ON.
200 V: Stops at main circuit
DC voltage below
approx. 200 V (160 V
for single-phase)
400 V: Stops at main circuit
DC voltage below
approx. 400 V.
Check the following:
• Power supply voltage
• Main circuit power supply
connections
• Terminal screws: Loose?
• Monitor
value
Confirm voltage (DC volt-
age) between terminals
"+1" and "-".
⇓
If there is no problem, the In-
verter may be faulty.
UV2 (Control power sup-
ply fault)
Inverter detected voltage fault
of control power supply dur-
ing running.
Replace the Inverter.
Fault Display
Inverter
Status
Description
Causes and Corrective
Actions
Digital
Operator
RUN (Green)
ALARM (Red)