Siemens SIRIUS 3RW4458-2BC34 Soft Starter
Siemens SIRIUS Soft Starter - Phased Out
The Siemens 3RW4458-2BC34 is a SIRIUS soft starter designed for smooth acceleration of three-phase motors. It provides controlled starting torque to reduce mechanical stress and electrical inrush current. Standard values at 50°C are 850 A and 750 hp (at 460 V), with inside-delta values reaching 1472 A and 1300 hp.
This soft starter is ideal for applications where high starting torque is needed without the mechanical shock of direct-on-line starting. Industries include pump controls, fan systems, conveyors, and compressors, offering a more controlled and efficient motor start-up compared to traditional methods.
This product is phased out, with the SIRIUS 3RW5 series being the successor, specifically the 3RW5556-2HA14. Stanlo Automation, a veteran-owned surplus distributor, may have this unit available for those maintaining existing systems. Always consider the successor for new installations.
| Series | SIRIUS |
| Model | 3RW4458-2BC34 |
| Standard Rating (460V, 50°C) | 850 A, 750 hp |
| Inside-Delta Rating (460V) | 1472 A, 1300 hp |
| Voltage Range | 200-460 V AC |
| Terminals | Spring-type terminals |
| Status | Phased-out product |