SIRIUS

Siemens SIRIUS is the control and protection portfolio for industrial motor management and switching applications. SIRIUS covers the full range of devices required to start, protect, monitor, and safely switch industrial motors and loads, including contactors, soft starters, overload relays, motor management systems, safety relays, and circuit protection components. SIRIUS hardware is installed across virtually every industrial sector. Motor starters and contactors in SIRIUS configurations manage pumps, conveyors, compressors, fans, and process machines across manufacturing, mining, water and wastewater, food processing, and energy production. Safety relays within the SIRIUS portfolio are used in machine guarding and emergency stop circuits where functional safety requirements apply.

PLC Direct supplies Siemens SIRIUS hardware to customers for maintenance and component replacement in existing SIRIUS installations. With over 10,000 products in this collection, it represents one of the most comprehensive areas of PLC Direct's Siemens inventory.

Where Siemens SIRIUS Hardware Is Used

SIRIUS switching and protection devices are present in motor control centers, panel boards, and control cabinets across almost every type of industrial facility. A failed contactor, soft starter, or safety relay in a motor circuit can take a pump, conveyor, or production machine offline until a replacement is installed.

Applications and facilities that rely on Siemens SIRIUS hardware include:

• Motor control centers in manufacturing plants, requiring contactor and overload relay replacement

• Mining operations running conveyors, crushers, and pumps with SIRIUS motor starters.

• Water and wastewater facilities managing pump motor protection and control.

• Food and beverage processing lines with high-cycle motor switching requirements

• Machine tool and packaging equipment using SIRIUS safety relays in guarding circuits

• Chemical and petrochemical plants with motor management requirements on process pumps

• Power generation and energy distribution facilities with high-current switching applications

• Building infrastructure and HVAC systems using SIRIUS soft starters on fan and pump motors

Siemens SIRIUS Products

The SIRIUS collection at PLC Direct spans motor contactors, soft starters, safety relays, motor management devices, and associated accessories. All product families and part number references below are confirmed on the live PLC Direct collection page.

Product Families

• SIRIUS Safety Relays (3TK28 Series): Safety relays for functional safety applications in machine guarding and emergency stop circuits. The 3TK2825-1BB40 provides relay-enabling circuits at 24 V DC, with a 45 mm width, including 3 NO instantaneous enabling contacts and 2 NC signaling contacts. The maximum achieved safety rating is SIL 3, PL e. The 3TK2827-1BB40 provides 2 NO instantaneous and 2 NO delayed enabling contacts (0.5 to 30 s adjustable) with SIL 3/2, PL e/d capability. Both are at the start of the final year of the support lifecycle status.

• SIRIUS Soft Starters (3RW44 and 3RW50 Series): Electronic motor soft starters for reduced-voltage motor starting and stopping. The 3RW44 series (e.g., 3RW4447-6BC34, rated 385 A / 300 hp at 460 V standard, 667 A / 600 hp inside-delta, 200-460 V AC) is a phased-out series with a successor in the SIRIUS 3RW5 range. The active 3RW50 series is currently in production: the 3RW5076-6AB14 is rated 470 A at 200-480 V with analog output capability, and is confirmed in stock.

• SIRIUS Power Contactors (3RT1 Series): AC motor contactors for standard duty motor switching. The 3RT1 series covers the full power range from compact to high-power motor applications. The 3RT1044-1AK60 is an AC-3-rated 65 A/30 kW contactor at 400 V with a 110 V AC coil (50/60 Hz), Size S3, though it is discontinued, with 3RT2 as its successor. The 3RT1046-1AK60 is a larger AC-3 contactor in the same series. Active 3RT2 series devices are the current platform.

• SIMOCODE Motor Management (3UF Series): Communication and interface accessories for SIMOCODE pro motor management systems. The 3UF7941-0AA00-0 is a USB PC cable for connection between a PC and SIMOCODE pro or SIRIUS 3RW44 / safety system 3SK2 and 3RK3 via the system interface, with a 2.5 m cable length.

Available at PLC Direct

• SIRIUS 3TK28 safety relays with SIL 3 / PL e ratings, 24 V DC, relay enabling circuits (3TK2825-1BB40, 3TK2827-1BB40)

• SIRIUS 3RW44 soft starters (phased out), including 385 A / 300 hp at 460 V standard configuration (3RW4447-6BC34)

• SIRIUS 3RW50 soft starters (active), including 470 A at 200-480 V with analog output (3RW5076-6AB14)

• SIRIUS 3RT1 power contactors including AC-3 65 A and larger sizes (3RT1044-1AK60, 3RT1046-1AK60)

• USB PC cables for SIMOCODE pro and SIRIUS 3RW44 system interface communication (3UF7941-0AA00-0)

What to Know Before You Buy Siemens SIRIUS Parts

SIRIUS hardware spans a very wide product range. Ordering the correct part requires matching the device type, current rating, coil voltage, and, where applicable, the safety rating and lifecycle status.

Hardware condition options: We supply SIRIUS hardware as surplus sealed, refurbished, and used. Surplus sealed units are factory-sealed stock. Refurbished units have been tested and restored to operational condition.

Contactor sizing: SIRIUS contactors are rated by AC-3 operational current and kilowatt rating at a reference voltage (typically 400 V). Confirm both the current rating and the coil voltage required for the motor circuit before ordering. Coil voltage is encoded in the part number suffix.

Soft starter succession: The SIRIUS 3RW44 soft starter series is being phased out, with the 3RW5 series as its successor. PLC Direct stocks both generations. For facilities maintaining existing 3RW44 installations, surplus sealed or refurbished 3RW44 units provide a direct-fit replacement. For new panel builds, the 3RW50 series is the current platform.

Safety relay SIL/PL ratings: SIRIUS 3TK28 safety relays carry IEC 62061 SIL and ISO 13849 PL ratings. Confirm that the safety relay selected meets the required SIL/PL level for the safety function being implemented before ordering.

Lifecycle awareness: Many SIRIUS 3RT1 contactor models are phased out or discontinued, with 3RT2 as the active successor. When the exact installed part number must be matched for a maintenance replacement, sourcing the legacy part from independent stock is typically the most direct option.

Warranty: All Siemens SIRIUS hardware purchased from PLC Direct includes a standard 1-year warranty covering defects and functionality, applicable to surplus sealed, refurbished, and used products.