Siemens SIMOVERT MV Series Commissioning Instructions page 26

The circuit-breaker is tripped via the safety relay.
♦
This contact changes from low to high for a circuit-breaker OPEN command. The
circuit-breaker is opened with a rising edge. This command circuit is not wire-
breakage proof.
♦
This contact changes from a high to a low for a circuit-breaker OPEN command.
The circuit-breaker identifies an undervoltage condition for a falling edge, and
opens. This command circuit is wire breakage proof.
For SIMOVERT drive converters, the circuit-breaker must be equipped with an
undervoltage release, in order to ensure that the circuit-breaker OPEN command is
wire-breakage proof.
The doors of the power section are monitored using limit switches. If this circuit is
interrupted, a circuit-breaker OPEN command is output via the SUL module, and
the crowbar thyristor is then triggered.
The relay contact of the buffer memory module is closed as soon as the SIMADYN
D subrack was initialized and cyclic program processing has started.
If the system crashes on a module in the SIMADYN D subrack, this relay drops-
out, and the circuit-breaker is opened.
Siemens AG 6SE8004-0BH76
26
SIMOVERT MV Commissioning Instructions