Siemens SIRIUS 3RH Series - Page 140

SIRIUS 3RT2 contactors/contactor assemblies
2.4 Configuration
SIRIUS Innovations
140 System Manual, 01/2011, A8E56203870002-03
φ = switchover current factor = switchover current peak/starting current peak
The switchover current factor has a theoretical maximum value of 2.
Example measurements:
Favorable circuit: φ = 0.8
Unfavorable circuit: φ = 1.37
Note
See the main and control circuit wiring designs below; these depict the circuit diagrams for
contactor assemblies for star-delta (wye-delta) start with clockwise and counterclockwise
rotation according to the preferred wiring.
Main circuit
The diagram below shows the preferred main circuit wiring for a star-delta circuit, clockwise
and counterclockwise rotation.
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Figure 2-16 Main circuit of the contactor assembly for star-delta (wye-delta) start