6-11
Possible Causes
What to Check and Suggested Measures
(3) Loads were too heavy.
Measure the motor current with a measuring device to trace the
current trend. Then, use this data to judge if the trend is over the
calculated load value for your system design.
If the load is too heavy, reduce it or raise the inverter capacity.
Trace the current trend and check if there are any sudden changes
in the current.
If there are any sudden changes, make the load fluctuation
smaller or raise the inverter capacity.
Enable instantaneous overcurrent limiting (H12 = 1).
(4) Excessive torque boost
specified.
(when F37, A13 = 0, 1, 3
or 4)
Check whether decreasing the torque boost (F09, A05) reduces the
output current but does not stall the motor.
If no stall occurs, decrease the torque boost (F09, A05).
(5) Acceleration/
deceleration time
currently specified is too
short.
Recalculate the acceleration/deceleration torque and time needed
for the current load, based on the moment of inertia of the load and
the acceleration/deceleration time.
Increase the acceleration/deceleration time (F07, F08, E10,
E11).
Enable current limiter (F43)
Raise the inverter capacity.
(6) Malfunction caused by
noise.
Check if noise control measures are appropriate (e.g., correct
grounding and routing of control and main circuit wires).
Implement noise control measures. For details, refer to the
FRENIC-Mini User's Manual, "Appendix A."
Enable the Auto-reset (H04).
Connect a surge absorber to magnetic contactor's coils or other
solenoids (if any) causing noise.
[ 2 ]
0u
n
Overvoltage
Problem
The DC link bus voltage was over the detection level of overvoltage.
0u1
Overvoltage occurs during the acceleration.
0u2
Overvoltage occurs during the deceleration.
0u3
Overvoltage occurs during running at constant speed.
Possible Causes
What to Check and Suggested Measures
(1) The power supply
voltage exceeded the
inverter's specification
range.
Measure the input voltage.
Decrease the voltage to within the specified range.
(2) A surge current entered
the input power supply.
In the same power line, if a phase-advancing capacitor is turned
ON/OFF or a thyristor converter is activated, a surge (momentary
large increase in the voltage or current) may be caused in the input
power.
Install a DC reactor.
