Siemens MICROMASTER 420 Operating Instructions Manual page 132

3 Functions
On the other hand, if the Vdc_max controller increases the output frequency (e.g.
for a steady-state regenerative load), then the Vdc_max controller is disabled by an
internal drive inverter monitoring function and warning A0910 is output. If the
regenerative load continues, the drive inverter is protected using fault F0002.
In addition to controlling the DC link, the Vdc_max controller supports the
stabilizing processes of the speed at the end of an acceleration phase. This is
especially the case if there is an overshoot and the motor therefore briefly goes into
regenerative operation (damping effect).
NOTE
If the DC link voltage exceeds the power-on threshold r1242 (switch-on level of
Vdc_max.) of the Vdc_max controller in the "Ready" state, then the Vdc_max
controller is de-activated and warning A0910 is output.
Cause:
Remedy:
If, in the "Run" state, the DC link voltage exceeds the power-on threshold r1242
and if the Vdc_max controller output is limited by parameter P1253 for approx.
200 ms, then the Vdc_max controller is de-activated and warning A0910 and,
where relevant, fault F0002 are output.
Cause:
Remedy:
The Vdc_max switch-in threshold V
V
DC_max
a) Auto-detect function enabled (P1254 = 1):
-
-
b) Auto-detect function disabled (P1254 = 0):
-
-
-
132
The line supply voltage does not match the application situation.
Refer to parameters P1254 and P0210.
Line supply voltage P0210 or ramp-down time P1121 too low
The moment of inertia of the driven load is too high
Refer to parameters P1254, P0210, P1121
(P1254 = 0) V
DC_max
V (P1254 = 1) is automatically calculated when the drive inverter
DC_max
runs-up, i.e. after the line supply voltage has been connected
Using the auto-detect function, the V
adapts itself to the line supply voltage at the particular installation
location.
U . 1 15 2 P 0210
DC _ max
The V threshold is immediately re-calculated after entering P0210
DC-Comp
P0210 must be adapted to the particular installation location.
depends on P1254
DC_max
(P1254 0)
threshold automatically
DC-Comp
MICROMASTER 420
Issue 07/04
Operating Instructions
6SE6400-5AA00-0BP0