Mitsubishi Electric FR-A700 Technical Manual page 120

3) When the output phase loss protection does
not function
When the motor capacity is too small as compared
to the inverter capacity, the output current becomes
too small. At this time, when the average output
current of all phases is 5% or less of the rated
inverter current, the output phase loss protection
(E.LF) does not function assuming that all phases
is 0A even if one of the three phases is lost since
all phases enter the dead zone (assumed as 0A if
within 5% of the rated inverter current value).
Output current
The output currents of all phases
are 5% or less than the rated current (dead zone)
5% of the
rating
Since in the dead zone, currents of all phases
are considered as 0A
1.5.10 Inverter status and reset method at occurrence of fault
Inverter Status Fault Occurrence
IGBT Gate is shut OFF instantly.
Frequency meter display Reset to 0Hz instantly
Operation panel Fault code indication
Fault description display
Frequency, current, et., at fault
Parameter unit display
occurrence can be read in the
monitor mode.
Excited instantly (terminals B-C
Fault output (relay output)
open)
RUN signal Switched OFF instantly.
SU signal Switched OFF instantly.
Reset or switch the power OFF,
Reset method
then ON
*1 If a fault has occurred, the IGBT gate is instantly shut off to stop the output. Hence, the inverter power may remain ON. If the
power is switched OFF by using the MC etc., the inverter control power is lost and the fault signal cannot be output. To keep
only the fault signal ON, keep the fault output contact (across terminals A-C) closed in the external circuit. The fault description
is stored in the inverter and can be read later.
U phase current
V phase current
W phase current
Time
When multiple motors are operated by a single
inverter, output phase loss protection (E.LF) does
not function.
The output phase loss protection (E.LF) functions
when one phase is lost. This function is invalid if
two phases or three phases are lost. Note that it
may functions even if two phases are lost when an
earth (ground) fault occurs. When an earth
(ground) fault occurs in the lost phase, output
phase loss protection (E.LF) may not function.
Reset terminal Connected
Gate is shut OFF instantly.
Reset to 0Hz instantly
Short terminals to erase the
indication once.
Keep RES signal ON to display
Short terminals to erase the
indication once.
Keep RES signal ON to display
(flicker) the communication fault
display screen.
Frequency and current at fault
occurrence are cleared.
Drops instantly (terminals B-C
closed)
Switched OFF instantly.
Switched OFF instantly.
Turn OFF RES signal
113
SPECIFICATIONS
common
(common)
Output Stop Terminal Connected
Gate is shut OFF instantly.
Reset to 0Hz instantly
Value being monitored is reset to 0
instantly. Note that this depends on
the data monitored.
Value being monitored is reset to 0
instantly. Note that this depends on
the data monitored.
No operation
Switched OFF instantly.
Switched OFF instantly.
Turn OFF MRS signal
1