Semiconductor soft starter 3RW3 SIKOSTART 3RW34 Drives with low demands on the functionality of the soft starter can be real- ized with a SIKOSTART 3RW34. SIKOSTART 3RW34 is very similar to the SIRIUS soft starter in terms of operation and features. It covers a power range up to 1000 kW (400 V). The functions of the 3RW34 can be summarized as follows: Soft starting and coasting 2 circuit variants: standard and delta 3-phase cycling Optional AS-i bus control The technical data and an exact description of the 3RW34 can be found in the document entitled SIKOSTART 3RW22/3RW34 - Electronic Soft Starters (Order No.: E20001-P285-A682-V2).
SIRIUS 3RW3 soft starter The SIRIUS 3RW3 soft starter covers the power range from 1.5 to 45 kW. Power semiconductors always have a dissipated power, which manifests itself in generation of heat. To minimize this power dissipation, the semicon- ductors are bypassed by relay contacts after the motor has started. Thus, it has been possible to keep the dimensions of the unit's heatsinks and thus also its overall dimensions small. Moreover, there is no need to use a bypass contactor, as is usually encountered in conventional designs to bypass the power semiconductors. The unit offers two relay outputs for further processing in the system con- trol:
"ON" - The unit offers two relay outputs for further processing in the sys- tem control). "BYPASSED" - contact (terminals 23/24) which signals the end of starting, e.g. to switch a solenoid valve after a soft started pump has started. For drives in this power range, good motor starting can be achieved with a 2- phase control. With a 2-phase control, semiconductor elements are only used in two phases, thus reducing the motor current and voltage in all three phases. The third phase is bypassed internally in the soft starter 8-14 Stand 08/99