12.9 L: Protection Functions
732 YASKAWA SIEPC71061753C GA500 Technical Manual
■ L8-15: Drive oL2 @ Low Speed Protection
No.
(Hex.)
Name Description
Default
(Range)
L8-15
(04BB)
Drive oL2 @ Low Speed
Protection
Sets the function to decrease the drive overload level at which the drive will trigger oL2 [Drive
Overload] during low speed operation (6 Hz or slower) to prevent damage to the main circuit
transistors.
1
(0, 1)
Note:
Contact Yaskawa or your nearest sales representative before disabling this function at low speeds. If you frequently operate drives with
high output current in low speed ranges, it can cause heat stress and decrease the life span of drive IGBTs.
0 : Disabled (No Additional Derate)
The drive does not decrease the overload protection level.
1 : Enabled (Reduced oL2 Level)
When the drive detects oL2 during low speed operation, it automatically decreases the overload detection level.
At zero speed, the drive derates the overload by 50%.
■ L8-18: Software Current Limit Selection
No.
(Hex.)
Name Description
Default
(Range)
L8-18
(04BE)
Software Current Limit
Selection
Set the software current limit selection function to prevent damage to the main circuit transistor
caused by too much current.
0
(0, 1)
0 : Disabled
When the output current is at the software current limit value, the drive does not restrict the output voltage.
Note:
The drive may detect an oC [Overcurrent] when loads are particularly heavy or the acceleration time is particularly short.
1 : Enabled
When the output current is at the software current limit value, the drive decreases output voltage to decrease
output current.
When the output current decreases to the software current limit level, the drive starts usual operation.
■ L8-19: Freq Reduction @ oH Pre-Alarm
No.
(Hex.)
Name Description
Default
(Range)
L8-19
(04BF)
Freq Reduction @ oH Pre-
Alarm
Sets the ratio at which the drive derates the frequency reference during an oH alarm.
0.8
(0.1 - 0.9)
When these two conditions are correct, this function is enabled:
• L8-03 = 4 [Overheat Pre-Alarm Ope Selection = Run@L8-19 Rate]
• oH alarm is output
■ L8-27: Overcurrent Detection Gain
No.
(Hex.)
Name Description
Default
(Range)
L8-27
(04DD)
Overcurrent Detection Gain
Sets the PM motor overcurrent detection level as a percentage of the motor rated current value.
300.0%
(0.0 - 1000.0%)
Note:
• If the setting value for L8-27 is the same or almost the same as the setting value for L7-xx [Torque Limit], the drive can detect oC2
[Overcurrent2].
• Set L8-27 = 0.0 Hz to disable this function. Usually do not set L8-27 = 0.0.
• If the drive rated current is much higher than the motor rated current, PM motor magnets can demagnetize when current flows at the
drive overcurrent detection level. When you set a low overcurrent detection level to prevent PM motor demagnetization, make sure that
you adjust L8-27.