What this SIRIUS S00 contactor is and what it does
The Siemens 3RT1015-2AR61 is a SIRIUS-branded power contactor in the compact S00 frame size, designed for switching motor loads in industrial control panels. It uses a 24 VDC coil and is rated for AC-2 duty at 3 kW on a 400 V supply — that's the category for slip-ring motors or wound-rotor applications where the contactor makes and breaks the load under normal running conditions. The AC-4 rating of 6.5 A at 400 V tells you it can handle the inrush of plugging or inching duty — frequent starts and reversals — which is the tougher thermal cycle for a contactor. For AC-3 (squirrel-cage motors, the most common category), the 3 kW AC-2 figure is a conservative proxy; the actual AC-3 rating would be higher, but the datasheet doesn't break it out separately here.
Mounting and integration into a panel
Mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022 — the standard for most industrial enclosures. The 45 mm width and 60 mm height fit neatly into a 12-module row on a 600 mm wide gland plate, leaving room for a motor-protective circuit breaker and a terminal block alongside. Depth of 73 mm means it clears most 120 mm deep enclosures with space for wiring behind the rail. Spring-loaded terminals on the main circuit accept 2x (0.25 to 2.5 mm²) solid or stranded wire, or 2x (24 to 14 AWG). That's a standard range for motor circuits up to 4 kW — no need for ferrule adapters on the smaller sizes, but the double-wire entry is handy for daisy-chaining the line side through a disconnect. Side-by-side mounting is allowed with a 6 mm clearance at the side — that's zero clearance between contactors if you're stacking them for a reversing pair or star-delta set. The front face carries IP20 protection, so the busbar and terminals are touch-safe once the panel door is closed.
Coil and control circuit — what the ratings mean
The 24 VDC coil draws 10 A at 24 V rated value — that's the pickup current, not the hold. The holding current will be lower, but the inrush matters for sizing your 24 VDC power supply. If you're running a bank of these, sum the pickup currents to avoid a voltage dip that drops out adjacent contactors. Coil operates reliably across 0.85 to 1.1 times the rated voltage at both 50 Hz and 60 Hz. That's a 20.4 V to 26.4 V window — tight enough that a sagging 24 V bus from a long cable run could cause chatter. Keep the DC supply local or use a regulated rail. The ambient range of -25 °C to +60 °C during operation covers most panel environments, but derate the continuous current above 40 °C per the thermal curve. Pollution degree 3 means it's rated for conductive pollution in industrial atmospheres — no extra conformal coating needed for a typical dry panel.
Short-circuit protection and coordination
For Type 2 coordination (no damage to the contactor after a short circuit), use a gL/gG fuse rated at 20 A. That's the standard choice for motor circuits where you want the contactor to survive a fault and be reusable. For Type 1 coordination (contactor may need replacement after a fault), the fuse can go up to 35 A. The 3 kW AC-2 rating at 400 V corresponds to roughly a 7 A full-load current for a 400 V motor — the 20 A fuse gives a 3:1 margin for starting inrush without nuisance blowing. For a 4 kW motor at 690 V, the same contactor handles it, but the fuse sizing should be checked against the motor nameplate FLA.