5.8 L: Protection Functions
204
YASKAWA ELECTRIC
SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual
■
L8-38: Carrier Frequency Reduction Selection
The drive can reduce the carrier frequency when the output current exceeds a certain level. This temporarily increases the
overload capability (oL2 detection) and the drive can 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 Open Loop Vector for PM motors.
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
Sets the delay time which is used to switch back to the normal carrier frequency. The carrier frequency reduction function
is disabled if this value is 0 s.
■
L8-41: High Current Alarm Selection
The drive can be set to trigger a high current alarm (HCA) when the output current rises too high.
Setting 0: Disabled
No alarm is output.
Setting 1: Enabled
An alarm is triggered when the output current exceeds 150% of the drive rated current. A digital output indicating an
alarm (H2-01, H2-02, H2-03 = 10) can be programmed.
■
L8-46: AVR Function Selection
Enables or disabled the AVR function. If enabled AVR adjusts the PWM to have the output voltage at the desired level
even if the DC bus voltage changes.
Setting 0: Disabled
Setting 1: Enabled
No.
Name
Setting Range
Default
L8-38
Carrier Frequency Reduction Selection
0 to 2
Determined by
o2-04
No.
Name
Setting Range
Default
L8-40
Carrier Frequency Reduction Off-Delay Time
0.00 or 2.00 s
0.50 s
No.
Name
Setting Range
Default
L8-41
High Current Alarm Selection
0 or 1
0
No.
Name
Setting Range
Default
L8-46
AVR Function Selection
0, 1
1
