Mitsubishi Electric FR-A700 Series, Техническое руководство

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112
SPECIFICATIONS
1.5.9 Input/output phase loss protection selection
(common)
(1) Input phase loss protection (E.ILF)
When [ Pr. 872 = 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.
*1
If input phase is lost when [
Pr. 872
= 1] (with input
phase loss protection) and [ Pr. 261 0]
(instantaneous power failure stop function is enabled)
are set in , input phase failure protection
(E.ILF) is not provided but power-failure deceleration is
made. For , input phase failure
protection (E.ILF) is activated.
(2) Output phase loss protection (LF)
The output current unbalance due to the phase loss
is checked by the output phase loss detection. When
the current value between the lost phase and other
two phases differs, it is regarded as output phase
loss and the inverter will come to a fault.
When [
Pr. 251 = 0], output phase loss protection
(E.LF) becomes invalid.
1) When the output phase loss protection
activates properly
The output phase loss protection (E.LF) activates
when
a) The average output current of the phase where
lowest current flows is 5% or less than the
rated inverter current
and
b) The difference between the average output
current of other two phases and rated inverter
current is 5% or more
2) When the output phase loss protection
malfunctions
When the motor capacity is smaller than the
inverter capacity, the output current value is small
as compared to the rated inverter current. At this
time, if any of the phases enters the dead zone
(assumed as 0A if within 5% of the rated inverter
current value) due to noises, etc. when the output
current flows more than 5% on average, the
output phase loss protection (E.LF) may
malfunction. To prevent this, set 0 in [
Pr. 251
Output phase loss protection selection ] and make
output phase loss protection invalid.
common
*1 As phase loss is detected according to the bus
voltage change in , phase loss cannot
be detected if the load is light. 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).
*2 When an input phase loss occurs in the R/L1 and
S/L2 phases of , input phase loss
protection is not provided but the inverter output is
shut off.
*3 If an input phase loss continues for a long time, the
converter section and capacitor lives of the inverter
will be shorter.
[Pr. ] Name
Initial
Value Setting
Range
Description
872
Input phase
loss
protection
selection
0
1
0
Without input
phase loss
protection
1
With input phase
loss protection
[Pr. ] Name
Initial
Value Setting
Range
Description
251
Output phase
failure
protection
selection
1
0
Without output
phase loss
protection
1
With output phase
loss protection
common
A700 F700
E700 D700
E700 D700
A700 F700
A700
F700
D700
E700
common
5% of the
rating
Output current
Time
U phase current
V phase current
W phase current
b)
a)
The average current exceeds 5%
Output current
Time
The period of time where the current
of one phase is instantly less than 5%
The current enters the dead zone
U phase current
V phase current
W phase current
5% of the
rating