Power-Off Function - KEB COMBIVERT F5 MULTI Applications Manual

Special Functions
6.9.6

Power-Off Function

Power-Off Mode (Pn.44)
Switch on Power-Off
(Pn.44 Bit 0)
Tripping of Power-Off
Fig. 6.9.6.a Starting the Power-Off function
ru.68 Rated DC voltage display
Auto-DC link voltage set
value measured at
Power-on
Pn.45 starting voltage
200...800 V
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It is the task of the Power-Off function to ensure a controlled deceleration of the
drive until standstill in case of undervoltage (e.g. due to power failure). The kinetic
energy of the rotating drive is used to support the inverter DC-link voltage. As a result
the inverter remains in operation and can decelerate the drive in a controlled manner.
Especially in the case of parallel running drives (e.g. textile machines) the uncontrolled
running down of the motors and the consequences resulting from it (thread breakage)
can be avoided.
The parameter Power-Off-Mode (Pn.44) switches on the function and determines the
basic behaviour:
8 7 6 5 4 3 2 1 0 Bit
Value Function
Switch on/off of Power-Off
x x x x x x x x 0 0
x x x x x x x x 1 1
Power-Off / start voltage
x x x x x x x 0 x 0
x x x x x x x 1 x 2
Determination of starting jump
x x x x x x 0 x x
0
x x x x x x 1 x x 4
Behaviour of drive at min. output
x x x x 0 0 x x x 0
x x x x 0 1 x x x 8
x x x x 0 0 x x x 16 Status PLS, modulation on, reset required
x x x x 1 1 x x x 24 reserved
reserved
x x x 0 x x x x x 0
x x x 1 x x x x x 32 reserved
Selection of setpoint
x 0 0 x x x x x x
0
x 0 1 x x x x x x 64 DC-voltage (Pn.50)
x 1 0 x x x x x x 128 actual voltage, if actual frequency is > Pn.48
x 1 1 x x x x x x 192 Braking torque (Pn.47)
DC-link voltage stabilization during Power-Off
0 x x x x x x x x
0
1 x x x x x x x x 256 Switched off
The Power-Off function is switched on/off with Bit 0 of Pn.44. Parameter Pn.44 is an
Enter-parameter.
The Power-Off function starts when the DC-link voltage drops below a certain value,
the start voltage. The start voltage can be set automatically or manually depending
on Pn.44 Bit 1.
Pn.44 Bit 1 starting voltage
Pn.46 Auto-start
0 auto detect starting
voltage 50...90%
(default 80%)
2 setting starting voltage by
Name: Basis
KEB COMBIVERT F5
Functional Description
off
on
Automatic determination of start voltage
Adjustment of start voltage with Pn.45
From the slip
From the utilization
Status Poff, modulation on, reset required
as above, but restart after network return (Pn.52)
reserved
Current voltage
Switched on
DC-link voltage real value
-
voltage
+
Pn.45
Date
04.05.04
Starting power off if
real value < set value
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