Siemens 3VA Auxiliary Contact and Undervoltage Release
The auxiliary and alarm switches for 3VA molded case circuit breakers can be installed in all sizes of all breakers up to 630 A. All auxiliary and alarm switches are designed as changeover contacts and therefore provide a high degree of flexibility for planning and installation purposes
Auxiliary switches signal the position of the main contacts of the molded case circuit breaker (RS 874-4534 and 874-4537) Trip alarm switches signal every circuit breaker trip, regardless of the cause of the trip (RS 874-4512 and 874-4515) Electrical alarm switches are operated as soon as the main contacts of the molded case circuit breaker open in the event that the breaker is tripped by the ETU (RS 874-4519) Short circuit alarm switches signal trips only if they have been initiated by a short circuit (RS 874-4528)
Undervoltage releases trip the molded case circuit breaker in the event that the rated voltage fails or drops to between 70 % and 35 % of its normal value (in compliance with the relevant standard) The units are available with rated voltages in the following range:
Shunt trips of type STL can be fitted in the left-hand accessories compartment as an alternative to an undervoltage release. The units are available with five rated voltages in the following range:
