Yaskawa AC Drive-P1000 Industrial Fan - Manual (Page 240)

Setting 4: KEB Ride-Thru as long as CPU Has Power
The drive decelerates using regenerative energy from the motor until the power returns and then restarts. If the motor comes
to a stop before the power returns, the drive loses control power and the drive output shuts off. A Uv1 fault is not triggered.
The type of KEB operation is determined by the L2-29 setting.
Setting 5: Ramp to Stop with KEB Deceleration
The drive ramps to stop using the regenerative energy from the motor. Even if the power is restored, the drive will continue
to decelerate until the motor comes to a complete stop. The type of KEB operation is determined by the L2-29 setting. If an
input terminal set for KEB 1 (H1-oo = 65, 66) is triggered while the drive is decelerating, it will accelerate back up to speed
when the input is released.
Notes on Settings 1 through 5
• “Uv” will flash on the operator while the drive is attempting to recover from a momentary power loss. A fault signal is not
output at this time.
• A Momentary Power Loss Unit is available to allow for a longer momentary power loss ride through time in models
2A0004 to 2A0056 and 4A0002 to 4A0031. This option makes it possible to continue running the drive after up to two
seconds of power loss.
• When using a magnetic contactor between the motor and the drive, keep the magnetic contactor closed as long as the drive
performs KEB operation or attempts to restart with Speed Search.
• Keep the Run command active during KEB operation or the drive cannot accelerate back to the frequency reference when
the power returns.
• When L2-01 is set to 3, 4, or 5, KEB Ride-Thru will be executed as specified in L2-29.
n KEB Ride-Thru Function
When the drive detects a power loss, KEB Ride-Thru decelerates the motor and uses regenerative energy to keep the main
circuit operating. Despite power loss, the drive output is not interrupted.
Choose between Single Drive KEB Ride-Thru 1 and 2 (L2-29 = 0 or 1 for applications driven by a single drive.
Choose between System KEB Ride-Thru 1 and 2, (L2-29 = 2 or 3) for applications where multiple drives have to perform
KEB operation while keeping a certain speed ratio.
Single Drive KEB Ride-Thru 1 (L2-29 = 0)
After KEB Ride-Thru begins, the drive uses regenerative energy from the motor to keep the DC bus voltage at the level set
to L2-11 while adjusting the rate of deceleration based on the time set to L2-06. The user must set L2-06 properly to prevent
Uv1 and ov faults.
Note: Shorten the KEB deceleration time (L2-06) if undervoltage (Uv1) occurs in the DC bus. Increase the KEB deceleration time if overvoltage
(ov) occurs.
Single Drive KEB Ride-Thru 2 (L2-29 = 1)
The drive uses information about the inertia of the connected machinery to determine the deceleration rate 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.
System KEB Ride-Thru 1 (L2-29 = 2)
The drive decelerates at the KEB deceleration time set to L2-06. L2-06 is the time required to decelerate from the current
frequency reference to 0. Using this setting, multiple drives can decelerate while keeping the speed ratio constant between
those drives. This function requires a braking resistor and disregards the voltage level in the DC bus.
System KEB Ride-Thru 2 (L2-29 = 3)
The drive decelerates based on the KEB deceleration time set to L2-06 while monitoring the DC bus voltage. If the voltage
level rises, the drive briefly holds the frequency before continuing to decelerate.
n KEB Ride-Thru Start
KEB operation is triggered independently of the selected KEB operation mode. When the KEB function is selected as the
function to be executed when power loss operation occurs (L2-01 = 3, 4, or 5), then KEB Ride-Thru will be activated if one
of the following conditions becomes true:
• A digital input programmed for H1-oo = 65 or 66 is activated. This will start KEB operation using the mode selected in
parameter L2-29.
• A digital input programmed for H1-oo = 7A or 7B is activated. This will automatically select Single KEB Ride-Thru 2,
disregarding the setting of L2-29.
5.8 L: Protection Functions
240 YASKAWA SIEP YAIP1U 01B AC Drive - P1000 Technical Manual