SIRIUS MCU with AS-Interface — 5 A motor duty
The 3RK4320-3KQ54-0BA2 is a Siemens SIRIUS motor starter MCU (Motor Control Unit) designed as a direct starter for AS-Interface networks. It integrates the contactor, overload relay, and communication interface into a single unit, saving panel space and wiring compared to a discrete starter build. It speaks AS-Interface natively (protocol supported), so it drops into an AS-i network without a separate gateway module. The control supply is 20.4–26.4 V DC, typical for AS-i power supplies, and the unit handles 50/60 Hz line frequencies.
Panel fit and mounting flexibility
Rated IP54, so it is protected against dust ingress and splashing water — suitable for installation inside a panel or in a protected machine cabinet. Ambient operating range is -25 to +50 °C, covering most industrial floor conditions without derating.
Motor protection and brake control
Motor protection is via a bimetal overload relay — the classic thermal model that tracks the motor's heating curve. Short-circuit protection is handled by upstream circuit breakers (not built-in), so coordinate the branch circuit breaker with the starter's 5 A AC-3 rating. The unit includes a motor brake output component (24 V DC brake control is not present, but the hardware is there for a brake option). Two digital inputs are available on-board for local sensors or pushbuttons, reducing the need for separate I/O modules. Minimum operating frequency is 80 cycles per hour — fine for normal start/stop duty; if you need higher cycling (e.g., rapid reversing), this starter is not the right fit.
Sourcing and lifecycle — active production
No stock-holding claim; we confirm per RFQ.