What it is and what it does
The Siemens SIRIUS 3RT1016-1AX21-0AA3 is a size S00 power contactor with a 24 VDC coil, part of the SIRIUS modular contactor system. It is designed for switching motor loads and resistive loads in industrial control panels, with screw-type terminals for the main current circuit. Rated for AC-2 duty at 4 kW at 400 V and AC-4 duty at 8.5 A at 400 V, this contactor handles both normal and reversing motor starts. The AC-12 rating of 10 A maximum covers resistive and solid-state load switching. Mounts via screw and snap-on onto a 35 mm DIN rail per EN 50022, with a 45 mm width that fits standard panel layouts. Side-by-side mounting is permitted, with a 6 mm clearance required at the side.
Key ratings and what they mean for fit
The 24 VDC coil draws 10 A at rated voltage — this is the holding current, not inrush. Verify your DC supply can sustain this without droop, especially on long cable runs or shared power rails. Motor ratings: 4.5 kW at 500 V and 5.5 kW at 690 V, both at 50/60 Hz. These are the maximum induction motor loads the contactor can switch under AC-3 duty (starting and stopping running motors). For reversing or plugging duty, use the AC-4 rating of 8.5 A at 400 V instead. The pollution degree 3 rating means the contactor is suitable for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation. This is standard for most control panels but not for clean-room or sealed electronics enclosures. Operating temperature range of -25 to +40 °C covers most indoor panel conditions. Above 40 °C, derating applies per the thermal curve — not listed here, so consult the full datasheet for elevated ambient installations.
Termination and wiring
Screw-type terminals accept 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or max 2x (0.75 to 4 mm²) solid or stranded conductors. AWG equivalents: 2x (20 to 16), 2x (18 to 14), or 1x 12. Strip length and torque values are standard for SIRIUS S00 — no special tooling required. One instantaneous auxiliary contact (NO or NC, not specified here) is included. For additional auxiliaries, the SIRIUS S00 system accepts side-mounted auxiliary contact blocks that snap onto the contactor without tools. Front and terminal protection is IP20 — finger-safe but not sealed. Suitable for dry indoor panels only; not rated for washdown or outdoor exposure.
Coordination and protection
For Type 2 coordination (no damage to the contactor after a short circuit), use a gL/gG fuse rated 20 A. For Type 1 coordination (contactor may need replacement after fault), a 35 A fuse is permitted. These values apply to the main circuit; the coil circuit requires separate overcurrent protection. Maximum operating altitude is 2 000 m without derating. Above that, dielectric strength and cooling decrease — consult the altitude derating factors in the full technical manual.
Lifecycle and sourcing
The 3RT1016-1AX21-0AA3 is the screw-terminal variant with a 24 VDC coil. The same contactor with spring-cage terminals (3RT1016-2AP02) or with different coil voltages (e.g., 230 VAC) are separate order codes — verify coil voltage and terminal type before substituting.