No.
Description Min. Max. Fact. sett.
671 Mains failure threshold -200.0 V -50.0 V -100.0 V
672 Reference mains support value -200.0 V -10.0 V -40.0 V
The frequency inverter reacts to the signals at the control inputs both when the power
failure regulation is switched on and in normal operation. A control via externally sup-
plied control signals is only possible in the case of a no
-break supply. As an altern
a-
tive, supply for the control signals through the frequency inverter is to be used.
Operation mode power failure regulation
The DC link voltage which is available in the case of a power failure is supplied by the
motor. The output frequency is continuously reduced and the motor with its
masses is switched over to generator operation. The maximum reduction of the out-
put frequency is done at the current set by the parameter
Gen. ref. current limit 683
or the ramp Mains support deceleration 673 until the frequency limit Shutdown
threshold
675 is reached. If the energy of the system for bridg
not sufficient, the delay is affected at maximum ramp gradient as from the Shutdown
The time required until the motor has come to a standstill results from the regenera-
tive energy of the system which results in an increase in the DC link voltage. The DC
link voltage set with the parameter Reference shutdown value 676
is used by the
voltage controller as a control figure and kept constant. The voltage rise enables
optimization of the braking behavior and the time until the drive has come to a
standstill. The behavior of the controller can be compared to stopping behavi
or 2
(Shutdown + Stop), as the voltage controller brings the drive to a standstill at the
maximum deceleration ramp and supplies it with the remaining DC link voltage.
If the DC-link voltage is restored before the shutdown of the drive, but after falling
below Shutdown Threshold 675, the drive is still decelerated to standstill.
If the mains voltage is restored after the shutdown of the drive but before the un-
dervoltage switch-
off has been reached, the frequency inverter signals a fault. The
control unit displays the fault message "F0702".
If the mains failure without shutdown (Shutdown threshold 675 = 0 Hz) takes so
long that the frequency has been reduced to 0 Hz, the drive is accelerated to the
reference frequency when the mains supply is restored.
214 Operating Instructions ACU 06/13
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