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SJ300 Inverter
Operations
and Monitoring
4–51
Instantaneous
Power Failure /
Under-voltage
Signal
An instantaneous power failure (complete loss) or under-voltage condition (partial loss) of
inverter input voltage can occur without warning. SJ300 Series inverters can be configured to
respond to these conditions in different ways. You can select whether the inverter trips or retries
(restart attempt) when an instantaneous power failure or under-voltage condition occurs. You
can select the retry function with parameter B001.
When enabled, the Retry Function operates in the following ways:
• Under-voltage conditions – When an instantaneous power failure or under-voltage condi-
tion occurs, the inverter will attempt to restart up to 16 times. A trip condition will occur on
the 17th attempt, which must be cleared with the Stop/Reset key.
• Over-current/voltage conditions – When retry function is selected and an over-current or
an over-voltage condition occurs, a restart is attempted 3 times. A trip will occur on the 4th
failed restart attempt. Use parameter B004 to select the trip and alarm response to instanta-
neous power failure and under-voltage conditions. The following table shows the related
parameters to these power fault conditions, and timing diagrams are on the next page.
Code Function Data or Range Description
B001 Selection of
automatic restart
mode
00 Alarm output after trip, automatic
restart disabled
01 Restart at 0 Hz
02 Retry with frequency matching to
present motor speed
03 Retry with frequency matching
followed by deceleration to stop—
then trip alarm
B002 Allowable under-
voltage power failure
time
0.3 to 1.0 sec. The amount of time a power input
under-voltage can occur without
tripping the power failure alarm. If
under-voltage exists longer than this
time, the inverter trips, even if the
restart mode is selected. If it exists
less than this time retry will be
attempted.
B003 Retry wait time
before motor restart
0.3 to 100 sec. Time delay after a trip condition goes
away before the inverter restarts the
motor
B004 Instantaneous power
failure / voltage trip
alarm enable
00 Disable
01 Enable
02 Disable during stop and ramp to stop
B005 Number of restarts
on power failure /
under-voltage trip
events
00 Restart up to 16 times on instanta-
neous power failure or under-voltage
01 Always restart on instantaneous
power failure or an under-voltage
condition
B007 Restart frequency
threshold
0.00 to 400.0 Hz When frequency of the motor is less
than this value, the inverter will
restart at 0 Hz