B" Group: Fine Tuning Functions - Hitachi SJ2002 Series Instruction Manual

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"B" Group: Fine Tuning Functions

"B" Group: Fine Tuning Functions

The "B" Group of functions and parameters adjust some of the more subtle but useful
aspects of motor control and system configuration.
Automatic Restart Mode
The restart mode determines how the inverter will resume operation after a fault causes a
trip event. The four options provide advantages for various situations. Frequency
matching allows the inverter to read the motor speed by virtue of its residual magnetic
flux and restart the output at the corresponding frequency. The inverter can attempt a
restart a certain number of times depending on the particular trip event:
• Over-current trip, restart up to 3 times
• Over-voltage trip, restart up to 3 times
• Under-voltage trip, restart up to 16 times
When the inverter reaches the maximum number of restarts (3 or 16), you must power
cycle the inverter to reset its operation.
Other parameters specify the allowable under-voltage level and the delay time before
restarting. The proper settings depend on the typical fault conditions for your applica-
tion, the necessity of restarting the process in unattended situations, and whether restart-
ing is always safe.
Power failure < allowable power fail
time (B002), inverter resumes
Input
power
0
Inverter
output
0
Motor
speed
0
Allowable
power fail time
Retry wait time
Instantaneous Power Failure / Under-voltage Alarm
Use parameter B004 to disable or enable the instantaneous power failure / undervoltage
alarm. When the alarm is enabled, parameter settings B001 (Selection of Automatic
Restart Mode) and B002 (Allowable Under-voltage Power Failure Time) are not valid.
free-running
Power fail
B002
B003
Power failure > allowable power fail
time (B002), inverter trips
Input
power
0
Inverter
output
0
Motor
speed
0
t
Power fail
B002
free-running
t
Allowable
power fail time