Initiating a protective function
A fault (protective function) is initiated by setting the parameter.
This function can be used to check how the system operates at activation of a protective function.
• To initiate a fault (protective function), set the assigned number of the protective function you want to initiate in Pr.997.
• The value set in Pr.997 is not stored in EEPROM.
• When a protective function activates, the inverter trips, a fault is displayed, and a fault signal (ALM, ALM2) is output.
• The latest fault in the faults history is displayed while the fault initiation function is in operation. After a reset, the faults
history goes back to the previous status. (The protective function generated by the fault is not saved in the faults history.)
• Perform inverter reset to cancel the protective function.
• For the selectable parameter by Pr.997 and the corresponding protective functions, refer to
• If a protective function is already operating, no fault can be activated by Pr.997.
• The retry function is disabled when a protective function has been initiated by the fault initiation function.
• If a fault occurs after a protective function has been activated, the protective function indication does not change. The fault is
not saved in the faults history either.
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
The setting is available only for standard models.
Output phase loss protection selection (Pr.251)
• When Pr.251 = "0", output phase loss (E.LF) protection is disabled.
Input phase loss protection selection (Pr.872) (Standard models)
• When Pr. 872 = "1", input phase loss (E.ILF) protection will be activated if one of three phases is detected to be lost for 1 s
• When several motors are connected, output phase loss cannot be detected even if the wiring to one motor loses phase.
• If an input phase is lost while Pr.872 = "1" (with input phase loss protection), Pr.261 Power failure stop selection ≠ "0"
(power failure stop function enabled), the motor decelerates to stop without outputting E.ILF.
• In the case of R/L1, S/L2 phase loss, the input phase loss protection will not operate, and the inverter will trip.
• If an input phase loss continues for a long time, the converter section and capacitor lives of the inverter will be shorter.
Parameters referred to
Pr.261 Power failure stop selection
16 to 253
(H) Protective function parameter
The setting range is same with the one for fault data codes of
the inverter (which can be read through communication).
Written data is not stored in EEPROM.
The read value is always "9999".
With this setting, the protective function does not activate.
Without output phase loss protection
With output phase loss protection
Without input phase loss protection
With input phase loss protection