YASKAWA GA700 Technical Manual page 946

11.9 L: Protection Functions
Kinetic
Energy
L2-29
Backup
Method
0 Single Drive The drive uses regenerative energy from the motor to
KEB Ride-Thru keep the DC bus voltage at the level set in L2-11 [KEB
1 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].
1 Single Drive The drive uses information about the inertia of the
KEB Ride-Thru connected machinery to find the deceleration rate
2 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.
2 System KEB The drive does not monitor the DC bus voltage. The
Ride-Thru 1 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.
3 System KEB The drive uses the KEB deceleration time set in L2-06
Ride-Thru 2 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.
■
KEB Ride Thru Start
When L2-01 = 3, 4, 5 [Power Loss Ride Through Select = Kinetic Energy Backup: L2-02, Kinetic Energy
Backup: CPU Power, Kinetic Energy Backup: DecelStop], the drive starts the KEB operation immediately after it
detects a momentary power loss. When one of these conditions occur, the drive will activate KEB Ride-Thru:
• KEB Ride-Thru 1 set for the MFDI terminal becomes enabled (terminal is deactivated when H1-xx = 65 or
terminal is activated when H1-xx = 66).
The drive uses the mode selected L2-29 [Kinetic Energy Backup Method] to start KEB operation.
• KEB Ride-Thru 2 set for the MFDI terminal becomes enabled (terminal is deactivated when H1-xx = 7A or
terminal is activated when H1-xx = 7B).
The drive automatically starts Single KEB Ride-Thru 2 and it ignores the setting of L2-29.
• The DC bus voltage is less than the level set in L2-05 [Undervoltage Detection Lvl (Uv1)].
The KEB operation will start as specified in L2-29.
Note:
If you try to set KEB Ride-Thru 1 and 2 to the MFDI terminals at the same time, it will trigger oPE03 [Multi-Function Input Setting
Err].
n this example, the drive detects that the DC bus voltage is less than the level set in L2-05 and starts the KEB
operation. When you return power during KEB operation, the drive will continue KEB operation when the KEB
Ride-Thru is input, although the time set in L2-10 [Minimum KEB Time] expired. The motor accelerates again
after you cancel the KEB Ride-Thru.
946
Table 11.70 KEB Ride-Thru Function Operation Method
Operation
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Configuration Precautions
• 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.
• 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 value of L3-20 and L3-21.
Use the dynamic braking option with System KEB
Ride-Thru 1.
If you cannot use the dynamic braking option, use
System KEB Ride-Thru 2.