Siemens 3RT1023-3AR60 — SIRIUS S0 Power Contactor
The Siemens 3RT1023-3AR60 is a SIRIUS-branded power contactor in the S0 frame size, rated for motor switching at 8.5 A in AC-4 duty at 400 V — the most demanding category for reversing or inching applications where the contactor makes and breaks stalled-rotor current. Terminals are screw-type for the main current circuit, accepting 2x (0.25…2.5 mm²) solid or 2x (1…2.5 mm²) stranded, up to 2x 10 mm² maximum — covers the range from control wiring to motor feeder cable in a single terminal block.
The 8.5 A AC-4 at 400 V rating is the load-bearing spec for reversing or jogging duty — the contactor must extinguish the arc of a locked-rotor current, which is harder than AC-3 (running start/stop). Type 1 coordination allows a 63 A fuse but may weld the contacts. Coil pickup at 50 Hz is 0.8…1.1 × rated voltage; at 60 Hz it's 0.85…1.1 × — the wider 50 Hz band accounts for the lower impedance at 50 Hz, meaning the coil draws more inrush current at the lower frequency. Ensure the control transformer is sized for the 50 Hz inrush if the line runs at 50 Hz.
Side-by-side mounting is permitted (zero clearance between units), which is typical for S0 contactors in multi-motor starter arrays — no derating required for adjacent mounting. The enclosure offers IP20 on the front (finger-safe) and IP00 at the terminals — the terminal area is not touch-protected, so the contactor must be installed inside a locked panel or behind a guard door.