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H09 and STM terminal command ("Enable auto search for idling motor speed at starting")
The combination of H09 data and the STM state determines whether to perform the auto
search as listed below.
Auto search for idling motor speed at starting
Data for H09 STM
For restart after momentary
power failure (F14 = 4 or 5)
For normal startup
0: Disable OFF Disable Disable
1: Enable OFF Enable Disable
2: Enable OFF Enable Enable
-- ON Enable Enable
When the inverter is equipped with any of output circuit filters OFL--2 and -4 in
the secondary lines, it cannot perform auto search. Use the filter OFL--
instead.
Auto search delay time (H49)
Auto search for the idling motor speed will become unsuccessful if it is done while the motor
retains residual voltage. It is, therefore, necessary to leave the motor for an enough time for
residual voltage to disappear. H49 specifies that time (0.0 to 10.0 sec.).
At the startup triggered by a run command ON, auto search starts with the delay specified by
H49. When two inverters share a single motor to drive it alternately, coast to stop it, and
perform auto search every switching, H49 can eliminate the need of the run command timing
control.
The H49 data should be the same value as the H13 data (Restart Mode after Momentary
Power Failure, Restart time). At the restart after a momentary power failure, at the start by
turning the terminal command BX ("Coast to a stop") OFF and ON, or at the restart by
auto-reset, the inverter applies the delay time specified by H13. The inverter will not start
unless the time specified by H13 has elapsed, even if the starting conditions are satisfied.
• Be sure to auto-tune the inverter preceding the start of auto search for the idling
motor speed.
• When the estimated speed exceeds the maximum frequency or the upper limit
frequency, the inverter disables auto search and starts in normal mode.
• In auto search with the restart after momentary power failure enabled (F14 = 4 o
5) and the allowable momentary power failure time specified (H16), turning a run
command ON will start auto search even if the time specified by H16 has elapsed.
• During auto search, if an overcurrent or overvoltage trip occurs, the inverte
restarts the suspended auto search.
• Perform auto search at 60 Hz or below.
• Note that auto search may not fully provide the expected/designed performance
depending on conditions including the load, motor parameters, power cable
length, and other externally determined events.
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