Input/Output Phase Loss Protection Selection (Pr. 251, Pr. 872); Earth (Ground) Fault Detection At Start (Pr. 249) - Mitsubishi Electric FR-E720-600 Instruction Manual

Operation setting at fault occurrence

4.14.2 Input/output phase loss protection selection (Pr. 251, Pr. 872)

You can disable the output phase loss protection function that trips the inverter if one phase of the inverter output side
(load side) three phases (U, V, W) is lost.
The input phase loss protection function of the inverter input side (R/L1, S/L2, T/L3) can be made valid.
Parameter
Number
Output phase loss
251
protection selection
Input phase loss protection
872
selection
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 180)
(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) is provided if a phase loss of one phase among the three
phases is detected for 1s continuously.
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. Also, if the
power supply voltage is imbalanced, phase loss is less likely detected.
Phase loss can not be detected during regeneration load operation.

4.14.3 Earth (ground) fault detection at start (Pr. 249)

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
Earth (ground) fault
249
detection at start
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 180)
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 277)
If the motor capacity is smaller than the inverter capacity for the FR-E720-240 or more, FR-E740-120 or more, earth (ground)
fault detection may not be provided.
164
Name Initial Value
Name Initial Value
Setting Range
0
1
1
0
1
1
Setting Range
0
0
1
Description
Without output phase loss protection
With output phase loss protection
Without input phase loss protection
With input phase loss protection
Description
Without earth (ground) fault detection
With earth (ground) fault detection