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Operation setting at fault occurrence
5.14.2 Input/output phase loss protection selection (Pr. 251, Pr. 872)
(1) Output phase loss protection selection (Pr. 251)
If phase loss occurs during inverter running (except for during DC brake operation, or output frequency is 1Hz or less),
output phase loss protection (E.LF) activates, and inverter trips.
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) is provided if a phase loss of one phase among the three
phases is detected for 1s continuously.
5.14.3 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 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
1
0 Without input phase loss protection
1 With input phase loss protection
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 167)
NOTE
If an input phase loss continues for a long time, the converter section and capacitor lives of the inverter will be
shorter.
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 protection (E.ILF).
Phase loss can not be detected during regeneration load operation.
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 parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 167)
NOTE
As detection is executed at start, output is delayed for approx. 20ms every start.
If an earth (ground) fault is detected while Pr. 249 = "1," the output side earth (ground) fault overcurrent (E.GF) is activated and
the inverter trips. (Refer to page 200)
If the motor capacity is smaller than the inverter capacity of the 5.5K or higher, earth (ground) fault detection may not be
provided.