Input/Output Phase Loss Protection Selection (Pr. 251, Pr. 872); Earth (Ground) Fault Detection At Start (Pr. 249) - Mitsubishi Electric FR-D720-0.2K-G Instruction Manual

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

You can choose whether to make Input/output phase loss protection valid or invalid.
 Output phase loss protection is a function to stop the drive unit output if one of the three phases (U, V, W) on the drive
unit's output side is lost.
 Input phase loss protection is a function to stop the drive unit output if one of the three phases (R/L1, S/L2, T/L3) on
the drive unit's input side is lost.
Parameter
Name
Number
Output phase loss
251
protection selection
Input phase loss protection
872
selection
The above parameters can be set when Pr. 160 Extended function display selection = "0". (Refer to page 161.)
(1) Output phase loss protection selection (Pr. 251)
 If a phase loss occurs at motor start-up or during drive unit operation (except for during DC injection brake operation, or
30r/min or less rotation speed operation), output phase loss protection (E.LF) activates, and the drive unit 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.
NOTE
 If an input phase loss under high load continues for a long time, the converter section and capacitor lives of the drive
unit will be shorter.
 If the load is light or during a stop, lost phase cannot be detected because input phase loss detection is performed
based on the fluctuation of bus voltage.
During the S-PM geared motor driving operation, lost phase cannot be detected because the drive unit has a one-rank
higher capacity compared to the motor, and the load is light for the drive unit capacity. When the load exceeds the
rated output, however, phase loss detection may be performed.
 Phase loss cannot be detected during regeneration load operation.

4.13.3 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 drive unit.
Protective function will not activate if an earth (ground) fault occurs during operation.
Parameter
Name
Number
Earth (ground) fault
249
detection at start
The above parameter can be set when Pr. 160 Extended function display selection = "0". (Refer to page 161.)
NOTE
 As detection is executed at start, output is delayed for approx. 20ms every start.
 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 drive unit trips. (Refer to page 260.) Even when a ground fault occurs, however, an overcurrent (E.OC3) may be detected
first to result in the output shutoff.
Operation setting at fault occurrence
Initial Value Setting Range
0
1
1
0
0
1
Initial Value 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
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