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Operation setting at fault occurrence
4.13.2 Input/output phase loss protection selection (Pr. 251, Pr. 872)
(1) Output phase loss protection selection (Pr. 251)
When Pr. 251 is set to "0", output phase loss protection (E.LF) becomes invalid.
(2) Input phase loss protection selection (Pr. 872)
When Pr. 872 is set to "1", input phase loss protection (E.ILF) becomes valid.
4.13.3 Earth (ground) fault detection at start (Pr. 249)
You can choose whether to make Input/output phase loss protection valid or invalid.
Output phase loss protection is a function to stop the inverter output if one of the three phases (U, V, W) on the
inverter's output side (load side) is lost.
Input phase loss protection is a function to stop the inverter output if one of the three phases (R/L1, S/L2, T/L3) on the
inverter's input side (load side) is lost.
Parameter
Number
Name Initial Value Setting Range Description
251
Output phase loss
protection selection
1
0 Without output phase loss protection
1 With output phase loss protection
872 ∗
Input phase loss protection
selection
0
0 Without input phase loss protection
1 With input phase loss protection
The above parameters can be set when Pr. 160 Extended function display selection = "0". (Refer to page 162)
∗ Available only for the three-phase power input specification model.
NOTE
If an input phase loss continues for a long time, the converter section and capacitor lives of the inverter will be
shorter.
As phase loss is detected according to the bus voltage change, it can not be detected if the load is light. Large
unbalanced phase-to-phase voltage of the three-phase power supply may also cause input phase loss protection
(E.ILF).
Phase loss can not be detected during regeneration load operation.
If parameter copy is performed from single-phase power input specification model to three-phase power input
specification model, Pr. 872 setting may be changed. Check Pr. 872 setting after parameter copy.
You can choose whether to make earth (ground) fault detection at start valid or invalid. Earth (Ground) fault detection is
executed only right after the start signal is input to the inverter.
Protective function will not activate if an earth (ground) fault occurs during operation.
Parameter
Number
Name Initial Value Setting Range Description
249
Earth (ground) fault
detection at start
0
0 Without earth (ground) fault detection
1 With earth (ground) fault detection
The above parameter can be set when Pr. 160 Extended function display selection = "0". (Refer to page 162)
NOTE
As detection is executed at starting, output is delayed for approx. 20ms every starting.
If an earth (ground) fault is detected with "1" set in Pr. 249, output side earth (ground) fault overcurrent (E.GF) is detected and
the inverter trips. (Refer to page 256)
If the motor capacity is smaller than the inverter capacity when using the FR-D720-238 or more, FR-D740-120 or more, earth
(ground) fault detection may not be provided.