Protective and Diagnostic Functions
7
-
3
Main Circuit Undervoltage
The main circuit DC voltage is below
the Undervoltage Detection Level
(L2-05).
200 V class: Approx. 190 V
400 V class: Approx. 380 V
Main Circuit MC Operation Failure
The MC stopped responding during
Inverter operation.
Applicable Inverter Capacities
200 V class: 37 to 110 kW
400 V class: 75 to 300 kW
• An open-phase occurred with the
input power supply.
• A momentary power loss occurred.
• The wiring terminals for the input
power supply are loose.
• The voltage fluctuations in the input
power supply are too large.
• A fault occurred in the surge pre-
vention circuit.
Reset the fault after correcting its
cause.
Control Power Fault
The control power supply voltage
dropped.
---
• Try turning the power supply
off and on.
• Replace the Inverter if the fault
continues to occur.
Inrush Prevention Circuit Fault
Overheating occurred in the inrush
resistor.
The MC did not respond for 10 s even
though the MC ON signal has been
output.
Applicable Inverter Capacities
200 V class: 37 to 110 kW
400 V class: 75 to 300 kW
• The MC in the main circuit failed.
• The MC excitation coil is burned
out.
• Try turning the power supply
off and on.
• Replace the Inverter if the fault
continues to occur.
Main Circuit Voltage Fault
The main circuit DC voltage oscillates
unusually (not when regenerating).
• An open-phase occurred in the input
power supply.
• A momentary power loss occurred.
• The wiring terminals for the input
power supply are loose.
• The voltage fluctuations in the input
power supply are too large.
• The voltage balance between phases
is bad.
Reset the fault after correcting its
cause.
Output Open-phase
An open-phase occurred at the
Inverter output.
• There is a broken wire in the output
cable.
• There is a broken wire in the motor-
winding.
• The output terminals are loose.
Reset the fault after correcting its
cause.
The motor being used has a capacity
less than 5% of the Inverter's maxi-
mum motor capacity.
Check the motor and Inverter
capacity.
(
)
Cooling Fin Overheating
The temperature of the Inverter's cool-
ing fin exceeded the setting in L8-02
or 105
°
C.
OH: The temperature exceeded the
setting in L8-02 (Stopping method can
be changed by L8-03.).
OH1: The temperature exceeded
100
°
C (Stopping method: Coast to
stop).
The ambient temperature is too high.
Install a cooling unit.
There is a heat source nearby.
Remove the heat source.
The Inverter's cooling fan has stopped.
Replace the cooling fan. (Contact
our sales representative.)
Inverter's Cooling Fan Stopped
The Inverter's cooling fan has stopped.
Table 7.1 Fault Displays and Processing (Continued)
Display
Description
Probable Causes
Corrective Actions
