Undervoltage detection enable/disable selection
A fault caused by unstable power supply voltage (undervoltage (E.UVT)) can be detected.
I/O phase loss protection selection
The output phase loss protection function, which stops the inverter output if one of the three phases (U, V, W) on the inverter's
output side (load side) is lost, can be disabled.
The input phase loss protective function on the inverter input side (R/L1, S/L2, T/L3) can be enabled.
Output phase loss
Input phase loss
Output phase loss protection selection (Pr.251)
is set to "0", output phase loss protection (E.LF) becomes invalid.
Input phase loss protection selection (Pr.872)
is set to "1", input phase loss (E.ILF) protection is activated if one of three phases is detected to be lost for 1
• When multiple motors are connected, output phase loss cannot be detected if the wiring to one motor loses phase.
• If the load is light or during a stop, lost phase cannot be detected because detection is performed based on the fluctuation of
bus voltage. Large unbalanced phase-to-phase voltage of the three-phase power supply may also cause input phase loss
• If an input phase is lost while "1" is set in Pr.872 (with input phase loss protection), and Pr.261 Power failure stop selection
≠ "0" (power failure stop function enabled), the motor decelerates to stop without outputting the input phase loss protection
• If an input phase loss continues for a long time, the lives of converter section and capacitor of the inverter become shorter.
Parameters referred to
Pr.261 Power failure stop selection
This function allows the inverter to reset itself and restart at activation of the protective function (fault indication). The retry
generating protective functions can also be selected.
When the automatic restart after instantaneous power failure function is selected (
operation is also performed after a retry operation as well as after an instantaneous power failure. (For restart operation, refer
Undervoltage detection disabled
Undervoltage detection enabled
Without output phase loss protection
With output phase loss protection
Without input phase loss protection
With input phase loss protection
Pr.57 Restart coasting time
≠ 9999), the restart
5.6 (H) Protective function parameter