Fuji Electric FRENIC-Multi User Manual

6-12
Possible Causes What to Check and Suggested Measures
(2) A surge current entered
the input power supply.
If within the same power supply a phase-advancing capacitor is
turned ON or OFF or a thyristor converter is activated, a surge
(temporary precipitous rise in voltage or current) may be caused in
the input power.
Î Install a DC reactor.
(3) The deceleration time
was too short for the
moment of inertia for
load.
Recalculate the deceleration torque from the moment of inertia fo
r
load and the deceleration time.
Î Increase the deceleration time (F08, E11, and H56).
Î Enable the regenerative braking (H69 = 2, 4), or deceleration
characteristics (H71 = 1).
Î Enable torque limiter (F41).
Î Set the rated voltage (at base frequency) (F05 and A03) to "0" to
improve braking ability.
(4) The acceleration time
was too short.
Check if the overvoltage alarm occurs after rapid acceleration.
Î Increase the acceleration time (F07 and E10).
Î Select the S-curve pattern (H07).
(5) Braking load was too
heavy.
Compare the braking torque of the load with that of the inverter.
Î Set the rated voltage (at base frequency) (F05 and A03) to 0 to
improve braking ability.
(6) Malfunction caused by
noise.
Check if the DC link bus voltage was below the protective level
when the alarm occurred.
Î Improve noise control. For details, refer to "Appendix A" of the
FRENIC-Multi User's Manual.
Î Enable the Auto-reset (H04).
Î Connect a surge absorber to the coil or solenoid of the magnetic
contactor causing the noise.
[ 3 ]
NW
Undervoltage
Problem DC link bus voltage was below the undervoltage detection level.
Possible Causes What to Check and Suggested Measures
(1) A momentary power
failure occurred.
Î Reset the alarm.
Î If you want to restart running the motor by not treating this
condition as an alarm, set F14 to "4" or "5," depending on the
load.
(2) The power to the
inverter was switched
back on too soon (with
F14 = 1).
Check if the power to the inverter was switched back on although its
control PCB was still operating. (Check whether the LEDs on the
keypad light.)
Î Switch the power ON again after all LEDs on the keypad go off.
(3) The power supply
voltage did not reach the
range of the inverter's
specifications.
Measure the input voltage.
Î Increase the voltage to within that of the specifications.

Fuji Electric FRENIC-Multi Specifications

General

Brand	Fuji Electric
Model	FRENIC-Multi
Category	Inverter
Language	English