YASKAWA GA700 Technical Manual page 834

11.9 L: Protection Function
L2-29 KEB Method
Selection
0 Single Drive The drive uses regenerative energy from the motor to
KEB Ride-Thru keep the DC bus voltage at the level set to L2-11 [DC
1 Bus Vol Setpoint during KEB] while adjusting the rate
of deceleration.
The KEB operation continues while the deceleration
rate is adjusted in accordance 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 determine the deceleration rate
2 necessary to keep the DC bus voltage at the level set in
parameter L2-11.
The resulting deceleration time is calculated based on
the system inertia and cannot be adjusted.
2 System KEB The drive does not monitor the DC bus voltage. The
Ride-Thru 1 drive decelerates at the KEB deceleration time set to
L2-06.
Set the time required to decelerate from the current
frequency reference to 0 Hz in L2-06. Multiple drives
can decelerate while keeping the speed ratio constant
between those drives..
3 System KEB The drive decelerates based on the KEB deceleration
Ride-Thru 2 time set to L2-06 while monitoring the DC bus voltage.
If the voltage level rises, the drive briefly holds the
frequency to prevent an ov before continuing to
decelerate.
■
KEB Ride Thru Start
When L2-01 = 3, 4, 5 [Momentary Power Loss Ope Select = KEB Mode, KEB Stop Mode, KEB Decel to Stp], the
drive starts the KEB operation immediately after a momentary power loss is detected. KEB Ride-Thru will be
activated if one of the following conditions becomes true:
• KEB Ride-Thru 1 set for the MFDI terminal becomes enabled (terminal is off when H1-xx = 65 or terminal is
on when H1-xx = 66).
The drive starts KEB operation using the mode selected L2-29 [KEB Method Selection].
• KEB Ride-Thru 2 set for the MFDI terminal becomes enabled (terminal is off when H1-xx = 7A or terminal is
ON when H1-xx = 7B).
The drive automatically starts Single KEB Ride-Thru 2, disregarding the setting of L2-29.
• The DC bus voltage fell below the level specified in L2-05 [Undervoltage Detect Level (Uv1)].
The KEB operation will start as specified in L2-29.
Note:
Attempting to simultaneously assign KEB Ride-Thru 1 and 2 to the MFDI terminals will trigger an oPE03 [Multi-Function Input Setting
Err].
In the following example, the drive detects that the DC bus voltage has dropped below the level set in L2-05 and
starts the KEB operation. If the power is restored while the KEB is operating, the drive continues KEB operation
as long as the KEB Ride-Thru is input even after the time set in L2-10 [KEB Detect Time (Min KEB Time)] has
elapsed. The motor reaccelerates once the KEB Ride-Thru is canceled.
834
Table 11.55 KEB Ride-Thru Function Operation Method
Operation
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
Configuration Precautions
• Set C1-09 appropriately so that Uv1 [DC Bus
Undervoltage] or ov [DC Bus Overvoltage] does not
occur.
• Decrease the value set in C1-09 if Uv1 is detected
during the KEB operation.
• Increase the value set in C1-09 if ov is detected
during the KEB operation.
• Increase the setting value of L3-20 [DC Bus Voltage
Adjustment Gain] and L3-21 [Accel/Decel Rate
Calculate Gain] if Uv1 is detected during the KEB
operation.
• Decrease the setting value of L3-20 and L3-21 if ov
is detected during the KEB operation.
Use the dynamic braking option with System KEB
Ride-Thru 1.
Use System KEB Ride-Thru 2 when the dynamic
braking option cannot be used.