2.9 L: Protection Functions
364 YASKAWA TOEPYAIGA5002A GA500 DRIVE PROGRAMMING
Note:
You can set this parameter when C6-02 = B [Carrier Frequency Selection = Leakage Current Detection Reduction Rate PWM].
If incorrect detection of alarms, for example oL1 [Motor Overload], occur or errors occur in the values on the current
monitor because of a leakage current, increase the setting value.
■ L1-23: Leakage Current Filter Time2
No.
(Hex.)
Name Description
Default
(Range)
L1-23
(0769)
RUN
Leakage Current Filter
Time2
Sets the leakage current detection reduction filter time constant during acceleration/deceleration.
Determined by C6-02
(0.0 - 60.0 s)
Note:
• You can set this parameter when C6-02 = B [Carrier Frequency Selection = Leakage Current Detection Reduction Rate PWM].
• When the setting value increases, the current monitor will start up slowly. Examine the relevant sequence for problems.
If errors occur in the values on the current monitor during acceleration/deceleration, increase the setting value.
◆ L2: Power Loss Ride Through
L2 parameters set the drive operation during momentary power loss and the KEB Ride-Thru function method of
operation.
■ KEB Ride-Thru Function
KEB is an acronym for Kinetic Energy Backup. If the drive detects a power loss or momentary power loss, it will
quickly decelerate the motor. The drive uses regenerative energy from the motor to keep the main circuit operating.
When you return power during motor deceleration, the drive returns operation to the status before the power loss. The
KEB Ride-Thru function is different than other functions for continuous operation. If the drive detects momentary
power loss, the motor will ramp to stop. It will not coast to stop. This function is applicable for applications in which
it is necessary to prevent materials from running out, for example control for film and fiber lines.
The KEB Ride-Thru function has 4 methods of operation. Parameter L2-29 [Kinetic Energy Backup Method] sets the
method.
When you use the KEB Ride-Thru function with one drive, set L2-29 = 0, 1 [Single Drive KEB Ride-Thru 1, Single
Drive KEB Ride-Thru 2].
If deceleration in coordination with more than one drive is necessary, for example textile machinery line systems, set
L2-29 = 2, 3 [System KEB Ride-Thru 1, System KEB Ride-Thru 2].
Table 2.58 KEB Ride-Thru Function Operation Method
L2-29
Kinetic Energy
Backup Method
Operation Configuration Precautions
0 Single Drive KEB
Ride-Thru 1
The drive uses regenerative energy from the motor to keep the DC bus
voltage at the level set in L2-11 [KEB DC Bus Voltage Setpoint] while it
adjusts the rate of deceleration.
The KEB operation continues while the drive adjusts the deceleration rate
with the setting of C1-09 [Fast Stop Time].
• Set C1-09 correctly to prevent Uv1 [DC Bus Undervoltage] and ov
[Overvoltage].
• If the drive detects Uv1 during the KEB operation, decrease the value
set in C1-09.
• If the drive detects ov during the KEB operation, increase the value
set in C1-09.
1 Single Drive KEB
Ride-Thru 2
The drive uses information about the inertia of the connected machinery
to find the deceleration rate necessary to keep the DC bus voltage at the
level set in parameter L2-11.
The drive uses system inertia to calculate the deceleration time. You
cannot adjust this value.
• If the drive detects Uv1 during the KEB operation, increase the setting
value of L3-20 [DC Bus Voltage Adjustment Gain] and L3-21
[OVSuppression Accel/Decel P Gain].
• If the drive detects ov during the KEB operation, decrease the setting
values of L3-20 and L3-21.
2 System KEB Ride-
Thru 1
The drive does not monitor the DC bus voltage. The drive decelerates at
the KEB deceleration time set in L2-06.
Use L2-06 to set the time necessary to decelerate from the current
frequency reference to 0 Hz. More than one drive can decelerate and
keep a constant speed ratio between drives.
Use the dynamic braking option with System KEB Ride-Thru 1.
3 System KEB Ride-
Thru 2
The drive uses the KEB deceleration time set in L2-06 to decelerate and
it also monitors the DC bus voltage.
If the voltage level increases, the drive momentarily holds the frequency
to prevent an ov before it continues to decelerate.
If you cannot use the dynamic braking option, use System KEB Ride-
Thru 2.
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