Fuji Electric FRENIC-HVAC User Manual page 460

Starting Mode (Auto search delay time 2) (H46)
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- Data setting range: 0.0 to 10.0 (s) (ROM version earlier than 2000)
0.0 to 20.0 (s) (ROM version 2000 or later)
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 H46. The inverter will not start unless the time specified by H46 has
elapsed, even if the starting conditions are satisfied.
Under auto search control, the inverter searches the motor speed with the voltage applied at
the motor start and the current flowing in the motor, based on the model built with the motor
parameters. Therefore, the search is greatly influenced by the residual voltage in the motor.
H46 is available for motor 1 only.
At factory shipment, H46 data is preset to a correct value according to the motor capacity for
the general-purpose motor, and basically there is no need to modify the data.
Depending on the motor characteristics, however, it may take time for residual voltage to
disappear (due to the secondary thermal time constant of the motor). In such a case, the
inverter starts the motor with the residual voltage remaining, which will cause an error in the
speed search and may result in occurrence of an inrush current or an overvoltage alarm.
If it happens, increase the value of H46 data and remove the influence of residual voltage. (If
possible, it is recommended to set the value around two times as large as the factory default
value allowing a margin.)
• 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 running the motor with the
maximum frequency or the upper limit frequency, whichever is lower.
• During auto search, if an overcurrent or overvoltage trip occurs, the inverter
restarts the suspended auto search.
• Perform auto search at 60 Hz or below.
• Note that auto search may not fully provide the performance depending on load
conditions, motor parameters, wiring length, and other external factors.
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