Instruction manual

8. Fault Diagnosis
163
 Corrective Actions of Models with Digital Operator
Alarm Display
Alarm Displays and Meaning
Alarm Display Inverter
Status
Description Causes and
Corrective Actions
Digital
Operator
RUN (Green)
ALARM (Red)
Flashing
Detected as
an alarm
only. Fault
contact out-
put is not ac-
tivated.
UV (Main circuit low volt-
age)
Main circuit DC voltage
dropped below the low-volt-
age detection level while the
Inverter output is OFF.
200 V: Main circuit DC volt-
age drops below ap-
prox. 200 V (160 V for
single-phase).
400 V: Main circuit DC volt-
age dropped below
approx. 400 V.
(Control supply fault) Control
power supply fault is detected
while the Inverter output is
OFF.
Check the following:
• Power supply voltage
• Main circuit power supply
connection.
• 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.
Flashing
OV (Main circuit over-
voltage)
Main circuit DC voltage ex-
ceeded the overvoltage de-
tection level while the Inverter
output is OFF.
Detection level:
200 V: approx 410 V or more
400 V: approx 820 V or more
Check the following:
• Power supply voltage.
• Monitor value
Confirm voltage (DC volt-
age) between terminals
"+1" and "-".
⇓
If there is no problem, the In-
verter may be faulty.
Flashing
OH (Heatsink overheat)
Intake air temperature in-
creased while the Inverter
output is OFF.
Check the following:
• Intake air temperature.
• There is no thermal
source around the
Inverter or that oil adher-
ing to the fan has deterio-
rated the cooling
capability.
• Fan is not clogged.
• Any foreign matters such
as water has entered in
the Inverter and adhered.
Flashing
CAL (MEMOBUS com-
munications waiting)
Correct data has not been re-
ceived from the PLC when
the constants n003 (Run
Command Selection) is 2 or
n004 (Frequency Reference
Selection) is 6, and power is
turned ON.
Check the following:
• Communications devices
and transmission signals.
• PLC is not faulty.
• Transmission cable is
connected properly.
• Wiring is made properly.
• Any loose terminal
screws do not result in
improper contact.
: ON : Flashing : OFF