Hitachi SJ2002 Series, Instruction Manual, Page: 112 / 306

“B” Group: Fine Tuning Functions
Configur
ing
Dr
iv
e P
a
ra
m
e
ters
3–32
“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.
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.
Input
power
Motor
speed
Power fail
t
0
0
Power failure < allowable power fail
time (B002), inverter resumes
0
Inverter
output
free-running
Input
power
Motor
speed
t
0
0
Power failure > allowable power fail
time (B002), inverter trips
0
Inverter
output
free-running
Allowable
power fail time
Retry wait time
Power fail
Allowable
power fail time
B002 B002
B003