7.5.6 Protective Functions: L
7-96
Output Open-phase Protection Selection: L8-07
D This function detects an Inverter output open-phase.
User
Change
Valid Access Levels
Constant
Number
Name
during
Opera-
tion
Setting
Range
Unit
Factory
Setting
V/f
Control
V/f with
PG
Open
Loop
Vector
Flux
Vector
L8-07
Output open-phase
protection selection
×
0, 1 − 0
A A A A
D Settings
Setting Function
0
Disabled.
1
Enabled. (Detects an output open-phase at under 10% of the Inverter’s rated output current.)
D
When the motor capacity is small compared to the Inverter capacity, false open-phase detection may
occur or open-phase cannot be detected. In this case, disable the detection function by setting L8-07
to 0.
Carrier Frequency Reduction Selection: L8-17 (for SPEC: F)
User
Change
Valid Access Levels
Constant
Number
Name
during
Opera-
tion
Setting
Range
Unit
Factory
Setting
V/f
Control
V/f with
PG
Open
Loop
Vector
Flux
Vector
L8-17
Carrier frequency re-
duction selection 2
×
0to3 − 1
A A A
×
D
Settings
Setting Function
0
No carrier frequency reduction.
1
With carrier frequency reduction.
2
For factory adjustments.
3
For factory adjustments.
D
If metallic noise (carrier noise) from the motor is a problem when carrier frequency is reduced (less
than 6 Hz), set L8-17 to 0 (no carrier frequency reduction), and L8-19 (OL2 characteristics selection
at low speeds) to 1 (enabled).
D
Do not L8-17 and L8-19 to 0 at the same time when using V/f control and open loop vector control.
OL2 characteristics Selection at Low Speeds: L8-19 (for SPEC: F)
User
Change
Valid Access Levels
Constant
Number
Name
during
Opera-
tion
Setting
Range
Unit
Factory
Setting
V/f
Control
V/f with
PG
Open
Loop
Vector
Flux
Vector
L8-19
OL2 characteristics
selection at low
speeds
×
0, 1 − 0
A A A A
D
Settings
Setting Function
0
OL2 characteristics at low speeds disabled.
1
OL2 characteristics at low speeds enabled.
D
When using OL2 to trip at low speeds (less than 6 Hz) despite a light load, set L8-17 to 1 (with carrier
frequency reduction) and L8-19 (OL2 characteristics selection at low speeds) to 0 (disabled).
However, do not set l8-19 to 0 for 400 V class, 185 to 300 kW Inverters.
D
Do not L8-17 and L8-19 to 0 at the same time when using V/f control and open loop vector control.
D
Reduce the carrier frequency (C6-01) to 2 kHz when continuously operating at low speeds with heavy
loads when using flux vector control.
7