11.9 L: Protection Functions
952 YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Note:
When you set L2-01, make sure that you know these items:
• You can use a Momentary Power Loss Unit on models 2004 to 2056 and 4002 to 4031 for a longer momentary power loss ride through
time. A Momentary Power Loss Unit makes it possible to continue operation of the drive after a maximum of 2 seconds of power loss.
• When you set L2-01 = 1 to4, keep the magnetic contactor between the motor and the drive closed and keep the control signal while the
drive does KEB operation.
• When you set L2-01 = 1 to 5, Uv [Undervoltage] will flash on the keypad while the drive tries to recover from a momentary power
loss. The drive will not output a fault signal at this time.
• When you use a magnetic contactor between the motor and the drive, keep the magnetic contactor closed while the drive does KEB
operation or tries to restart with Speed Search.
• Keep the Run command active during KEB operation. The drive cannot accelerate back to the frequency reference when the power
returns.
• When you set L2-01 = 3 to 5, if the control power supply voltage is less than the CPU operation level during KEB Ride-Thru, it will
trigger Uv1.
■ L2-02: Power Loss Ride Through Time
No.
(Hex.)
Name Description
Default
(Range)
L2-02
(0486)
Power Loss Ride
Through Time
Sets the maximum time that the drive will wait until trying to restart after
power loss.
Determined by o2-04
and C6-01
(0.0 - 25.5 s)
This function is applicable when L2-01 = 1, 3 [Power Loss Ride Through Select = Enabled for L2-02 Time,
Kinetic Energy Backup: L2-02]. If power loss operation is longer than the time set in this parameter, the drive will
detect Uv1 [DC Bus Undervoltage], turn OFF output, and the motor will coast to stop.
Note:
• The length of time that the drive can recover after a power loss changes when drive capacity changes.
• The upper limit of the possible momentary power loss Ride-Thru time changes when drive capacity changes.
■ L2-03: Minimum Baseblock Time
No.
(Hex.)
Name Description
Default
(Range)
L2-03
(0487)
Minimum Baseblock
Time
Sets the minimum baseblock time when the drive restores power after a
momentary power loss.
Determined by o2-04
and C6-01
(0.1 - 5.0 s)
Sets the length of time that the drive will wait for the residual voltage in the motor to dissipate in estimation to the
secondary circuit time constant of the motor. If oC [Overcurrent] or ov [DC Bus Overvoltage] occur at the start of
Speed Search, after a power loss, or during DC Injection Braking, increase this setting.
■ L2-04: Powerloss V/f Recovery Ramp Time
No.
(Hex.)
Name Description
Default
(Range)
L2-04
(0488)
Powerloss V/f
Recovery Ramp Time
Sets the time for the drive output voltage to go back to correct voltage after
completing speed searches.
Determined by o2-04
and C6-01
(0.0 - 5.0 s)
Sets the time for voltage to recover from 0 V to the value set in E1-05 [Maximum Output Voltage].
■ L2-05: Undervoltage Detection Lvl (Uv1)
No.
(Hex.)
Name Description
Default
(Range)
L2-05
(0489)
Undervoltage
Detection Lvl (Uv1)
Sets the voltage at which a Uv1 [DC Bus Undervoltage] fault is triggered or
at which the KEB function is activated. Usually it is not necessary to change
this setting.
Determined by E1-01
(Determined by E1-
01)
NOTICE: Damage to Equipment. Install an AC reactor option on the input side of the power supply when setting this parameter
lower than the default value. Failure to obey will cause damage to drive circuitry.
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