B&C Technologies SA Series Industrial - Manual (Page 70)

TROUBLE SHOOTING
7-10
2. “OUn” Overvoltage protection
Problem The DC link circuit voltage was over the detection level of overvoltage.
OU1 Overvoltage occurs during the acceleration.
OU2 Overvoltage occurs during the deceleration.
OU3 Overvoltage occurs during running at constant speed.
Possible Causes What to Check and Suggested Measures
1. The power supply voltage
was over the range of the
inverter’s specifications.
Measure the input voltage.
→ Decrease the voltage to within that of the specifications.
2. The acceleration time was
too short.
Check if the overvoltage alarm occurs after sudden acceleration.
→ Increase the acceleration time (F07, E10, and H54).
→ Select the S – curve pattern (H07).
→ Consider the use of a braking resistor.
3. The deceleration time was
too short for the moment
of inertia for load.
Recalculate the deceleration torque from the moment of inertia for
load and the deceleration time.
→ Increase the deceleration time (F08, E11, and H54).
→ Enable automatic deceleration (H69=1) so that when the DC
link circuit voltage exceeds the overvoltage suppression level,
the inverter changes the deceleration time to three times
longer than the set value.
→ Set the rated voltage (at base frequency) (F05) to 0 to improve
braking ability.
→ Consider the use of a braking resistor.
4. Loads were suddenly
removed.
Check if the alarm occurs when loads are suddenly removed.
→ Check if the inverter operation suddenly changes from driving
operation to braking operation.
→ Consider the use of a braking resistor.
5. Braking load was too
heavy.
Compare the braking torque of the load with that of the inverter.
→ Set the rated voltage (at base frequency) (F05) to 0 to improve
braking ability.
→ Consider the use of a braking resistor.
6. Malfunction caused by
noise.
Check if the DC link circuit voltage was below the protective level
when the alarm occurred.
→ Improve noise control.
→ Enable the auto-reset function (H04).
3. “LU” Undervoltage protection
Problem DC link circuit voltage was below the undervoltage detection level.
Possible Causes What to Check and Suggested Measures
1. An instantaneous power
failure occurred.
Reset the alarm.
→ If you want to restart running the motor without making the
alarm occur, set 4 or 5 to F14 depending on load.