YASKAWA OYMC V1000

1.8 L: Protection Functions
194 YASKAWA ELECTRIC SIEP C710606 10A YASKAWA AC Drive - V1000 PRELIM. Programming Manual
This setting rarely needs to be changed.
When setting L2-05 lower than the default setting, be sure to install an AC reactor option to
the input side of the power supply to prevent damage to drive circuitry.
■ KEB Function
In case of a power loss, the KEB function (Kinetic Energy Backup) can decelerate the motor
and use the rotational energy of the machine to back up the drives DC bus for a certain
period of time. This allows the drive to continue running without interrupting the output
power during a momentary power loss. Once the power is restored, the drive smoothly
returns to the same operational state before the power loss occurred. The KEB function
supports two different operation modes.
KEB 1
In this mode the drive decelerates the motor based on the deceleration time set in parameter
L2-06 / C1-09 in order to keep the DC bus voltage level high. When the power supply
returns, it uses the time set to L2-07 or the selected acceleration time to accelerate back to
the frequency reference.
Figure 1.77
Figure 1.77 KEB Ride-Thru Timing Diagram
Note: If L2-06 is set to 0.0 s, C1-09 is used instead. If of L2-07 is set to 0.0 s, the drive reaccelerates
using the selected acceleration time.
Use this method with setting parameters L2-06 and L2-07 if multiple drives must decelerate
but still keep the speed ratio between the drives constant during power loss.
The KEB 1 mode requires a braking resistor in order to avoid overvoltage trips.
KEB2
In this mode the drive decelerates the motor by calculating the energy of the rotating system.
The deceleration rate is continuously adjusted so that the DC bus voltage meets the level set
in parameter L2-11. The rotational energy is estimated using the parameters L3-24 and L2-
KEB Ride-Thru
(H1- = 65 or 66)
Output
frequency
OFF ON OFF
L2-06
L2-07