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3G3JV Maintenance Operations Chapter 7
7-1 Protective and Diagnostic Functions
7-1-1 Fault Detection (Fatal Error)
The Inverter will detect the following faults if the Inverter or motor burns or the
internal circuitry of the Inverter malfunctions. When the Inverter detects a fault, the
fault code will be displayed on the Digital Operator, the fault contact output will
operate, and the Inverter output will be shut
off causing the motor to coast to a stop.
The stopping method can be selected for some faults, and the selected stopping
method will be used with these faults. If a fault has occurred, refer to the following
table to identify and correct the cause of the fault. Use one of the following methods
to reset the fault
after restarting the Inverter. If the operation command is being
input, however, the reset signal will be ignored. Therefore, be sure to reset the
fault with the operation command turned
off.
• Turn on the fault reset signal. A multi-function input (n36 to n39) must be set to 5
(Fault
Reset).
• Press the STOP/RESET Key on the Digital Operator.
• Turn the main circuit power supply
off and then on again.
Fault Displays and Processing
Fault
display
Fault name and meaning Probable cause and remedy
oC Overcurrent (OC)
The Inverter output current is
as high as or higher than
200% of the rated output
current.
• A short-circuit or ground fault has occurred and at the
Inverter output.
-> Check and correct the motor power cable.
• The V/f setting is incorrect.
~ Reduce the V/f set voltage.
• The motor capacity is too large for the Inverter.
~ Reduce the motor capacity to the maximum permissible
motor capacity.
• The magnetic contactor on the output side of the Inverter
has been opened and closed.
~ Rearrange the sequence so that the magnetic contactor
will not open or close while the Inverter has current
output.
• The output circuit of the Inverter is damaged.
-> Replace the Inverter.
ou
Overvoltage (OV)
The main circuit DC voltage
has reached the overvoltage
detection level (200-V models:
410 V DC min.; 400-V
models:
820 V DC min.).
• The deceleration time is too short.
-> Increase the deceleration time.
• The power supply voltage is too high.
~ Decrease the voltage so it will be within specifications.
• There is excessive regenerative energy due to overshooting
at the time of acceleration.
-> Suppress the overshooting as much as possible.
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