SIRIUS S2 power contactor — what the ratings mean for your panel
The Siemens 3RT1035-3BB40-ZX95 is a SIRIUS-branded power contactor in the S2 frame size, rated for 22 kW at 400 V in AC-3 duty — that is the motor-switching curve for standard squirrel-cage induction motors, so it handles a 22 kW load directly without a separate starter. The 24 V DC coil draws 10 A at rated voltage (holding current is lower, but the inrush is what the PLC output must handle). For reversing or plugging duty (AC-4), the contactor is rated 35 A at 400 V — that is the current it can interrupt under the harsher switching conditions of a motor reversing or inching application. Mounts via screw and snap-on onto 35 mm DIN rail per EN 50022, and side-by-side mounting is permitted — no derating gap required between units in a row. Main current circuit uses screw-type terminals; the solid wire range is 2x (0.25 to 2.5 mm²) and stranded goes up to 2x (25 mm²) — sized for the full rated current without needing lugs.
Lifecycle and sourcing posture
RoHS compliance is documented with a substance prohibition date of May 1, 2012, covering the standard EU restricted substances.
Environmental and mounting constraints
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C — the storage limit governs handling during transport and warehouse idle, not running conditions. Front of the contactor carries IP20 (finger-safe), while the terminal area is IP00 — the panel builder must ensure the live terminals are behind a gland plate or cover. Degree of pollution 3 means it is rated for conductive pollution environments typical of industrial control panels — no conformal coating required for normal factory air.
Mechanical endurance and switching frequency
Mechanical life is rated at 10 million operations typical — this is the contactor body, not the contacts under load. Maximum switching frequency varies by duty: 1200 cycles/hour at AC-1 (resistive), 1000 at AC-3 (motor running), 600 at AC-2 (slip-ring motor), and 300 at AC-4 (reversing/plugging).