Protective and Diagnostic Functions
7-
3
Drive Faults
Drive faults are detected by the main control units. If any of these faults occurs, it is displayed on the Digital
Operator, and its detail is recorded in the memory.
Table 7.1 List of Drive Faults
Fault Display
Rank
Fault Details
Corrective Actions
IOV
Overvoltage
F
Power supply overvoltage
Voltage rose up to 120% of rated power sup-
ply voltage (L9-01).
• Check the main power supply voltage.
• Confirm that the detected value of the
power supply voltage (U1-90) and the
setting value of the rated main power
supply input voltage (L9-01) are appro-
priate.
• If detection is faulty, replace the isolation
board, which detects input voltage, or the
modulator board.
• Take measures to adjust the power supply
voltage (changing taps of transformer
etc.).
UVL
Under Voltage2
A
Power supply voltage reduction
Voltage reduced to 70% of rated power sup-
ply voltage (L9-01).
IUV
Under Voltage
F
Power supply voltage reduction
Voltage reduced to 55% of rated power sup-
ply voltage (L9-01).
CUV
CTL PS UnderVolt
F
Control power supply fault
Control power supply was lowered.
Exclusive contact signal input from the 5-V
power supply board.
• Check the control power supply.
• Replace the 5-V power supply board.
IOC
Over Current
F
Drive overcurrent
The Inverter output current exceeded the
overcurrent detection level (132% of rated
current).
• Check the load.
OOV
Output OV Fault
F
Output overvoltage
The Inverter output voltage (L9-06) exceeded
the overvoltage detection level (L9-07).
• Check the motor constants.
Constants: E1-
, E2-
• Confirm that the settings of L9-06 and
L9-07 are appropriate.
• Check the output cable connection.
TME
Tr Overtemp
F
Transformer temperature fault (input terminal
DI_1)
A fault detected from a contact input terminal
on the control board.
Note Check the actual external terminal number with the
elementary wiring diagram. The external terminal
number varies for each Inverter.
• Check to see if the transformer is over-
heated.
• Check the contact input terminal status.
• Check the mechanical system and correct
the cause of the fault.
FAN1
Fan Fault 1
F
Cooling fan fault 1(input terminal DI_2)
A fault detected from a contact input terminal
on the control board.
Note Check the actual external terminal number with the
elementary wiring diagram. The external terminal
number varies for each Inverter. When using more
than one cooling fan, faults may be found in multi-
ple contact input terminals (FAN2 to 4).
• Check the cooling fan’s operation and the
contact input terminal status.
• Replace the cooling fan or the ventilation
louver. (Normally, input terminals need to
be activated within 10 seconds after fan
operating commands (both on and off)
are sent.
OL1
Motor Overloaded
F/A
Motor Overload
(Operation selection – L1-04)
The motor overload protection function has
operated based on the internal electronic ther-
mal value.
• Check the Motor Rated Current (E2-02).
• Confirm that the settings of detection
(L1-02, L1-06, and L1-07) are appropri-
ate.
• Check the size of the load and the length
of the acceleration, deceleration, and
cycle times.
