6-36
Setting Precautions
• Error output signals are not output during momentary power loss recovery.
• To continue Inverter operation after power has been restored, make settings so that Run Commands from
the control main circuit terminal are stored even while power is suspended.
• To enable momentary power loss detection, a backup (UPS etc.) of the control power supply has to be
made.
Speed Search
The speed search function finds the actual speed of the motor that is rotating using inertia, and then starts
smoothly from that speed. When restoring power after a temporary power loss, the speed search function
switches connection from the commercial power supply, and then restarts the fan that is rotating using inertia.
Related Constants
Constant
Number
Name
Description
Setting
Range
Factory
Setting
Change
during
Operation
Control
Methods
MEMOBUS
Register
Open-
loop
Vector
Flux
Vector
Display
b3-01
Speed search
election (current
detection or speed
calculation)
Enables/disables the speed
search function for the Run
Command and sets the speed
search method.
0: Disabled, speed calculation
1: Enabled, speed calculation
2: Disabled, current detection
3: Enabled, current detection
Speed Calculation:
When the search is started, the
motor speed is calculated and
acceleration/deceleration is
performed from the calculated
speed to the specified
frequency (motor direction is
also searched).
Current Detection:
The speed search is started
from the frequency when
power was momentarily lost
and the maximum frequency,
and the speed is detected at the
search current level.
0 to 3
0
*1
No A A 1C0H
SpdSrch at Start
b3-02
Speed search
operating current
(current detection)
Sets the speed search operation
current as a percentage, taking
the Inverter rated current as
100%.
Not usually necessary to set.
When restarting is not possible
with the factory settings, reduce
the value.
0 to
200
30%
*1
No A No 1C1H
SpdSrch Current
b3-03
Speed search
deceleration time
(current detection)
Sets the output frequency
deceleration time during speed
search in 1-second units.
Set the time for deceleration
from the maximum output fre-
quency to the minimum output
frequency.
0.1 to
10.0
2.0 s No A No 1C2H
SpdSrch Dec Time
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