Hitachi SJ Series, User Manual

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12-14-3
Chapter 12 Inverter Function
12.14.3 Starting by picking up frequency
• How to start operation with the frequency matched
with the motor idling speed
• How to start operation matched with frequency at
the time of trip retry, free-run stop, reset, power-on,
etc.
• To achieve these goals when the motor is idling
due to a trip or terminal function, enable the
frequency matching function so that the inverter is
started by picking up frequency applied to each
function.
• Obtain the cycle of the motor residual voltage to
start operation.
• Frequency matching lower limit setting [bb-42] is
the parameter common to frequency matching
functions.
(Ex. 1) The motor speed is equal to or more than the
frequency matching lower limit setting.
Parameter
• For the retry function, see "12.13 Using Trip
Avoidance Function" as well.
• Even if frequency matching restart is selected, the
inverter may restart with 0 Hz if:
1. the output frequency is equal to or lower than
1/2 of the base frequency,
2. the voltage induced on the induction motor
quickly attenuates, or
3. the frequency matching lower limit setting
[bb-42] is set and the inverter detects a
frequency equal to or lower than that.
• If the restart after free-run stop or the restart after
reset is performed, the inverter will restart after the
retry wait time after instantaneous power
failure/under-voltage has elapsed.
• The restart after free-run stop and the restart after
reset will be performed if the operation command is
continuously input via a terminal command or other
ways.
• If the frequency matching restart does not go well
because the residual voltage rapidly decreases or
for other reasons, it may go well by using the
frequency pull-in restart. See "12.14.4 Starting with
frequency pull-in".
(Ex. 2) The motor speed is equal to or lower than the
frequency matching lower limit setting
Item Parameter Data Description
Frequency matching lower
limit setting
[bb-42] 0.00~590.00(Hz)
When the detected value is equal to or
lower than the set value, the inverter
restarts with 0 Hz.
Q
A
!
!
Retry wait time
Free-running
Power failure
factor
Inverter
output
Motor speed
Lower limit
setting
[bb-42]
Restart with 0 Hz
Retry wait time
Free-running
Power failure
factor
Inverter output
Motor speed
Lower limit
setting
[bb-42]
Restarting with frequency matching