3RV Motor Starter Protectors/Circuit Breakers up to 100 A General data Switching of direct current 3RV1 motor starter protectors for alternating currents are also suitable for DC switching. The response values of the overload release remain unchanged; the response values of a short-circuit release increase by appro- ximately 30 % for DC. The example circuits for DC switching can be seen in the table below. The maximum permissible DC voltage per conducting path must, however, be adhered to. Higher voltages require a series connection with 2 or 3 conducting paths.
Example circuit for size S00 to S3 3RV1 motor starter protectors 1) It is assumed that this circuit always provides safe disconnection even in the event of a double ground fault that bridges two contacts. 3RV16 voltage transformer circuit breakers up to 3 A The voltage transformer circuit breaker protects the secondary side of voltage transformers used to connect protection equip- ment with voltage-dependent starting. The circuit breaker is used for distance protection with low-impedance starting. Spe- cial auxiliary contacts reliably prevent low-impedance starting from triggering distance protection if only one fault has occurred in the transformer line.
The voltage transformer circuit breaker can also be used to sa- fely disconnect the distance protection device from the voltage transformer. In this case, the special auxiliary contacts also pre- vent false tripping of the distance protection. Additional fuses are not required. A "Fuse Failure Monitor" (FFM) is also not required.
12 Siemens · 2009 Example circuit for size S00 to S3 3RV1 motor starter protectors Maximum permitted DC voltage Ue Notes L+ L M NSB0_00001a 150 V DC Three-pole switching, non-grounded system1) If there is no possibility of a ground fault, or if every ground fault is rectified immediately (ground-fault monitoring), then the maximum permitted DC voltage can be tripled. L+ L M NSB0_00002a 300 V DC Two-pole switching, grounded system The grounded pole is always assigned to the individual conducting path, so that there are always 2 conducting paths in series in the event of a ground fault. L+ L M NSB0_00003a 450 V DC Single-pole switching, grounded system 3 conducting paths in series.
The grounded pole is assigned to the unconnected con- ducting path.