What this SIRIUS contactor is and what it does
The Siemens 3RT1025-1BB40-ZW98 is a SIRIUS-brand power contactor in the S0 frame size, designed for switching motor loads and resistive loads in industrial control panels. It carries a 24 VDC coil and is rated for AC-3 duty at 11 kW on 690 V and 10 kW on 500 V — the figures that govern real motor switching, not just the thermal current. The S0 frame means it occupies a 45 mm width on the DIN rail, with a depth of 101 mm and height of 85 mm. It mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022, so it drops into any standard panel without adapter brackets.
Key ratings and what they mean for fit
The AC-3 motor-switching rating is the one that matters for most BOM lines: 11 kW at 690 V and 10 kW at 500 V. This contactor handles induction motors up to those power levels in standard starting duty. For reversing or plugging duty, the AC-4 rating of 15.5 A at 400 V is the limiting figure — that's the current it can break during inching or counter-torque stops without accelerated contact wear. The 24 VDC coil draws 5.4 W both on closing and holding, so the control transformer or DC supply needs to sustain that continuously, not just a pickup surge. The operating temperature range of -25 to +60 °C covers most unheated plant floors, and pollution degree 3 means it's rated for conductive dust and humidity typical of industrial environments — not just clean switchgear rooms. For short-circuit coordination, type 2 (no damage to the contactor) requires a 25 A gL/gG fuse upstream; type 1 (contactor may need replacement) allows a 63 A gL/gG fuse. That's a practical difference when designing a panel with selective coordination requirements.
Mounting and wiring
Screw-type terminals on the main circuit accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid conductors. For AWG, that's 2x (16 to 12), 2x (14 to 10), or 1x 8. Side-by-side mounting is permitted with 6 mm spacing at the side — no derating required for adjacent units in the same row. Front protection is IP20, which is standard for enclosed panels; the terminal area itself is IP00, so live parts are exposed when the contactor is not inside an enclosure. That's normal for panel-mount gear but worth noting for any maintenance access.
Lifecycle and sourcing reality
Sourcing is straightforward: quoted to order against an RFQ. The SIRIUS platform is widely stocked globally, so lead times are predictable for this frame size. No need to broker or hunt surplus — genuine is genuine through any authorized channel.