YASKAWA A1000 Technical Manual page 300

5.8 L: Protection Functions
Setting 2: IP20/NEMA 1, UL Type 1 enclosure
For drives compliant with IP20/NEMA 1, UL Type 1 enclosure specifications.
Setting 3: Finless drive or external heatsink Installation
For finless drives or a standard drive mounted with the heatsink outside the cabinet or enclosure panel.

L8-38: Carrier Frequency Reduction Selection
Lets the drive reduce the carrier frequency when the output current exceeds a certain level. This temporarily increases the
overload capability (oL2 detection), allowing the drive to run through transient load peaks without tripping.
L8-38 selects the operation of the carrier frequency reduction function.
Note: This function cannot be used in Advanced Open Loop Vector for PM motors.
No.
L8-38
Setting 0: Disabled
No carrier frequency reduction at high current.
Setting 1: Enabled for output frequencies below 6 Hz
The carrier frequency is reduced at speeds below 6 Hz when the current exceeds 100% of the drive rated current. The
drive returns to its normal carrier frequency when the current falls below 88% or the output frequency exceeds 7 Hz.
Setting 2: Enabled for entire frequency range
The carrier frequency is reduced at the following speeds:
• Below 6 Hz when the current exceeds 100% of the drive rated current.
• Above 7 Hz when the current exceeds 112% of the drive rated current.
The drive uses the delay time set in parameter L8-40 and a hysteresis of 12% when switching the carrier frequency back
to the set value.

L8-40: Carrier Frequency Reduction Off-Delay Time
The following settings are used when the carrier frequency is to be reduced at start:
• Time taken for the reduced carrier frequency to return to the carrier frequency set at C6-02.
• Time taken to return to the set carrier frequency after reducing it by setting L8-38 to 1 or 2.
The carrier frequency reduction function at start is disabled if this value is 0.00 s.
No.
L8-40

L8-41: High Current Alarm Selection
Triggers a high current alarm (HCA) when the output current rises too much.
No.
L8-41
Setting 0: Disabled
No alarm is detected.
Setting 1: Enabled
An alarm is triggered when the output current exceeds 150% of the drive rated current. A digital output set for an alarm
(H2- = 10) will close.

L8-55: Internal Braking Transistor Protection
Enables or disables protection for the internal braking transistor.
Note: This parameter is not available in models CIMR-A4A0930 and 4A1200.
No.
L8-55
300
Name
Carrier Frequency Reduction Selection
Name
Carrier Frequency Reduction Off-Delay Time
Name
High Current Alarm Selection
Name
Internal Braking Transistor Protection
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
Setting Range
Determined by A1-02,
0 to 2
C6-01 and o2-04
Setting Range
0.00 to 2.00 s Determined by A1-02
Setting Range
0 or 1
Setting Range
0 or 1
Default
Default
Default
0
Default
1