Configuration
8200SHB01997-12
7.4.3 Change parameter set via DC-bus voltage
Only series “HVAC”
7.4.3.1 AC-motor braking by means of parameter set changeover
Code Possible settings IMPORTANT
No. Name Lenze Choice
C988* DC-bus voltage
threshold for
DC-bus voltage
control
0 0 {1 %} 200
-
C988 = 0 %
- Parameter set changeover
deactivated via DC-bus voltage
-
Changeover always between PAR1
and PAR2
-
Parameter set changeover via
terminal, bus or PC is not possible if
C988 > 0!
Function With the parameter set changeover in dependence of the DC-bus voltage, the AC motor braking
can be used as alternative for DC braking.
-
The AC motor braking is a braking method without external brake resistor for the control mode
“V/f-characteristic control with linear characteristic” (C014 = -2-)”.
-
With mains voltages up to approx. 3 AC 400 V it is possible to achieve braking times shorter
than with the DC-brake.
-
The braking times for generative braking via external brake resistor are approx. 33 %shorter
than for AC motor braking.
Configuration of the
parameter sets
Code PAR1 setting
(active in normal
operation)
PAR2 setting
(active in braking operation)
Note
C013C
105
Braking time required
for AC braking
Deceleration time of the drive with
max. inertia load without getting the
message OU (overvoltage) during
deceleration.
-
C0013 for braking along
the main setpoint ramp
-
C0105 for braking along
the QSP ramp
C015 Value adapted to the
drive,
e.g. V/f vertex = 50 Hz
Depending on the drive power up to
min. 25 % of the value under C015 in
PAR1 :
-
Rule of thumb: 2.2 kW Õ 50 %
-
Decrease for lower drive power,
increase for higher drive power.
Thus the energy in the
motor is decreased by
overexcitation in PAR2.
C016 Value adapted to the
drive,
e.g. V
min
=5%
Depending on the drive power up to
500 % of the value under C0016 in
PAR1 :
-
Rule of thumb: 2.2 kW Õ factor 3
-
For lower drive power increase the
factor, for higher power decrease it.
Thus also in the lower
speed range, the energyin
the motor is decreased by
overexcitation in PAR2.
C988 Threshold
Setting according to the mains voltage:
400 V Õ 112 %
440 V Õ 123 %
460 V Õ 129 %
480 V Õ 133 %
Important
-
AC motor braking can only be used together with the control mode “V/f-characteristic control
with linear characteristic” (C014 = -2-).
-
Parameter set changeover is not possible via terminal, bus or PC, if C988 > 0!
-
The higher the mains voltage, the longer the deceleration time for AC braking must be set in
PAR1, to fulfill the requirements stated above. It is therefore possible to achieve shorter
deceleration times with the DCB, if the mains voltage is high.
-
C988isthesameinallparametersets.
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