Mitsubishi Electric FR-A700 Technical Manual page 118

1.5.8 Instantaneous power failure protection (IPF)
(1) Instantaneous power failure protection
(IPF)
A700
F700
If the power supply voltage of the inverter has
reduced or the power is lost due to instantaneous
power failure, etc., this function activates the
protective circuit and shuts off the IPM gate to stop
the output.
Operation is continued properly if the instantaneous
power failure is within 15ms (fault output is not
provided). If it exceeds 15ms, the instantaneous
power failure protection circuit is activated to stop the
inverter output. A fault output is provided (terminals B
and C are open) when the instantaneous power
failure is within approximately 100ms. When the
power failure is longer than approximately 100ms,
fault output is not provided. (Refer to page 35.)
When the power is restored after the instantaneous
power failure, the inverter must be restarted after the
motor has stopped completely.
Set a value other than 9999 in [Pr. 57 Automatic restart
after instantaneous power failure] to make a restart
while the motor is coasting.
(2) Power supply undervoltage protection
(UVT)
A700
F700
Activates the protective function if the power supply
voltage drops below
(approximately 300VAC for the 400V class).
Power
supply
When using the other
power supply for control
circuit
(Refer to page 36.)
approximately 150VAC
R/L1, S/L2, T/L3
MCCB
MC
Power
OFF time
detection
(100ms)
Reset signal
RES
SD
R1/L11
S1/L21
Instantaneous Power Failure Protection Circuit Block Diagram
111
A700 F700
(common)
(3) Reset
A700
F700
Once activated, the instantaneous power failure
protection function remains activated. To reset,
switch OFF the start signal, then recovers the inverter
by referring to page 96.
The protective circuit is automatically reset by the
reset function if the power failure persists for longer
than approximately 100ms.
[Explanation of the instantaneous power failure
protection circuit block diagram]
When the inverter power supply (R/L1, S/L2, T/L3) is
switched ON, the converter smoothing capacitor (C) is
charged. In the meantime, when the control power supply
establishment pulse resets the instantaneous power failure
protection circuit to the initial state. If the DC voltage of the
smoothing capacitor is reduced by an instantaneous power
failure (longer than 15ms and within approximately 100ms)
or a power supply voltage reduction during inverter
operation, the undervoltage detection circuit is activated to
set the instantaneous power failure protection circuit and
shut off the inverter at the gate. When the power is then
restored, a fault display is switched ON (terminals B-C
open, A-C closed).
The reset function is activated when the inverter power
remains OFF for more than approximately 100ms. (Fault is
not output).
If the fault output relay is switched ON (terminals B-C open,
A-C closed) by other than the instantaneous power failure
protection circuit to switch OFF the inverter power supply
MC, the control power is lost, whereby the fault display and
fault output relay are switched OFF (terminals B-C closed,
A-C open).
Converter
Inverter
+
C
Instantaneous
Undervoltage
power failure
detection
detection
Power supply
Set
Instantaneous
power failure
Reset
protection
circuit
Other protective
function
Control
power
supply
SPECIFICATIONS
Motor
U, V, W
I M
detection
Fault output
relay
R
A
A1
Fault output
B1
C1
1