YASKAWA GA800

12.9 L: Protection Functions
968 YASKAWA SIEPC71061737D GA800 Drive Technical Reference
The drive starts deceleration through KEB operation. When the motor decelerates for the time set in L2-10, the drive
measures the DC bus voltage and the status of the digital input set for KEB Ride-Thru. When the DC bus voltage is
less than the level set in L2-11, or if the digital input set to KEB Ride-Thru is active, deceleration continues. When the
DC bus voltage is more than the level set in L2-11, the drive ends KEB operation. The drive accelerates the motor to
the frequency reference value before the power loss, and usual operation continues. When the KEB Ride-Thru
continues to be input after the time set in L2-02 is expired, the drive uses the KEB Ride-Thru function to continue to
decelerate. When you cancel the KEB Ride-Thru, the motor accelerates again, and usual operation continues.
Figure 12.127 Use the KEB Ride-Thru to Cancel KEB Operation when Restoration of Power Occurs while the Control
Power (Power Supply to the Control Board) is Maintained
*1 When L2-07 = 0.00 s, the drive accelerates again as specified by the applicable Acceleration Time [C1-01, C1-
03, C1-05, C1-07], and usual operation continues.
KEB Operation when L2-01 = 5 [Kinetic Energy Backup: DecelStop]
The drive starts deceleration through KEB operation. If you do not input the Run command, the motor cannot restart.
The drive will continue to decelerate until the motor comes to the minimum output frequency or a complete stop. If
you return power during deceleration, the drive continues to decelerate.
■ KEB Operation Wiring Example
Figure 12.128 shows an example that uses an undervoltage relay to trigger the KEB Ride-Thru at power loss. When a
power loss occurs, the undervoltage relay triggers KEB Ride-Thru [H1-06 = 65, 66, 7A, 7B] at terminal S6.
Note:
• Set the drive to activate the Run command while the KEB function is operating. If you turn off the Run command, the drive will not
accelerate back to speed when you return power.
• When you set L2-29 = 2 [Kinetic Energy Backup Method = System KEB Ride-Thru 1], install a dynamic braking option.