01.04 Start-up
SIEMENS AG 6SG7000-0BA76 7-17
SIMOTRAS HD Operating Instructions
7.6.15 Setting the rotor contactor stepping
Specifying limit values for switching over the rotor contactors (see Section 3.3.6 and 3.3.7):
On every control characteristic curve (in other words at a particular rotor resistance), the maximum
possible torque reduces as the speed increases. As a result, the converter switches to the next
rotor stage at the speed where the maximum possible torque is just 100% in order to receive an
appropriate acceleration torque (switchover points S2, S3 and S4 in Fig. 7.6.15.1)
see also Section 6.1 Block diagram
100
80
60
40
20
%
% 0
0
140 180
100
60 20
-20
-40
-60
-80
-100
40 80 120 160
Full load curve
Lift
M
n
Switch over to next
torque characteristic
Switchover point
S4 S3 S2
Activation of
rotor contactors:
Stage 4
Stage 3
Stage` 2
Stage 1
(Start-up stage)
Full load curve
Lower
Current limit
Switchover point S1b
(see Section 7.6.16)
Switchover point S1a
(see Section 7.6.16)
Mzus.
Counter-torque stage
Y
Fig. 7.6.15.1 Rotor contactor switching cycle
• with increasing speed:
U634 Value at which the rotor contactor for stage 2 is to be connected
U636 Value at which the rotor contactor for stage 3 is to be connected
U638 Value at which the rotor contactor for stage 4 is to be connected
• with decreasing speed
:
U638 (– U639 hysteresis)
Value at which the rotor contactor for stage 4 is to be disconnected
U636 (– U637 hysteresis)
Value at which the rotor contactor for stage 3 is to be disconnected
U634 (– U635 hysteresis)
Value at which the rotor contactor for stage 2 is to be disconnected
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