8-14
8.6 Protective Functions
Name Description
LED
monitor
displays
Alarm
output
[30A,B,C]
During
acceleration
OC1
During
deceleration
OC2
Overcurrent
protection
- Stops the inverter output to protect the
inverter from an overcurrent resulting from
overload.
- Stops the inverter output to protect the
inverter from an overcurrent due to a short
circuit in the output circuit.
- Stops the inverter output to protect the
inverter from an overcurrent due to a ground
fault in the output circuit. This protection is
effective only when the inverter starts. If you
turn on the inverter without removing the
ground fault, this protection may not work.
During running
at constant
speed
OC3
Yes
During
acceleration
OU1
During
deceleration
OU2
Overvoltage
protection
The inverter stops the inverter output upon
detecting an overvoltage condition (400 VDC for
3-phase 200V, 1-phase 200V, and 1-phase 100V
series; 800 VDC for 3-phase 400V series) in the
DC link circuit.
This protection is not assured if excess AC line
voltage is applied inadvertently.
During running
at constant
speed
(Stopped)
OU3
Yes
Undervoltage
protection
Stops the inverter output when the DC link circuit voltage drops
below the undervoltage level (200 VDC for 3-phase 200V, 1-
phase 200V, and 1-phase 100V series; 400 VDC for 3-phase 400
V series).
However, if data "4 or 5" is selected for F14, no alarm is output
even if the DC link circuit voltage drops.
LU
Yes
*1
Input phase
loss protection
Detects input phase loss, stopping the inverter output. This
function prevents the inverter from undergoing heavy stress that
may be caused by input phase loss or inter-phase voltage
unbalance and may damage the inverter.
If connected load is light or a DC reactor is connected to the
inverter, this function will not detect input phase loss if any.
In single-phase series of inverters, this function is disabled by
factory default.
L
Yes
Output phase
loss protection
Detects breaks in inverter output wiring at the start of running and
during running, stopping the inverter output.
OPL
Yes
Inverter - Stops the inverter output upon detecting excess heat sink
temperature in case of cooling fan failure or overload.
OH1
Yes
ver
ea
protection
Braking
resistor
- When the built-in or external braking resistor overheats,
discharging and the operation of the inverter are stopped.
* It is necessary to set the function code data according to the
braking resistor used (built-in or external).
dbH
Yes
Overload
protection
Stops the inverter output if the Insulated Gate Bipolar Transistor
(IGBT) internal temperature calculated from the output current
and cooling fan temperature detection is over the preset value.
OLU
Yes
In the following cases, the inverter stops running the motor to
protect the motor in accordance with the electronic thermal
function setting.
Motor protection
Electronic
thermal
overload
relay
- Protects general-purpose motors over the entire frequency
range.
- Protects inverter motors over the entire frequency range.
* The operation level and thermal time constant can be set.
OL1
Yes
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