SIEMENS
SINAMICS DCM
Accessories and supplementary components
Circuit breakers and contactors
4/22
Siemens D 23.1 · 2014
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Overview
The main contactor or the circuit breaker in front of the three-
phase armature circuit infeed of the converter is used to switch
on the power section in a correct manner when the electronics
and the voltage for the thyristor modules is enabled if the unit
is still not operational. This is the reason that the contactor or
the circuit breaker must always be energized via terminals
XR1-109-110. When a circuit breaker is used, a motor-operated
mechanism must be used to close the circuit breaker and an
undervoltage release to open the circuit breaker.
Selection criteria
The internal control sequence guarantees that the switching
operations are always made in a no-current condition. When
selecting the main contactor, the utilization category AC-1 or for
a circuit breaker, the maximum rated current
I
n max
should be
used as basis. If the current and voltage quantities permit it, then
generally, the more cost-effective solution using a contactor is
preferred over a circuit breaker.
© Siemens AG 2014