The S3 frame is the mid-size in the SIRIUS contactor family, balancing contact rating with panel footprint.
Coil circuit and control voltage
The coil is rated for a control voltage of 20... 33 V, with a pickup threshold at 0.8 of rated value and a dropout level at 0.55 of rated value. Inrush current peaks at 6.5 A, then settles to a holding power of 3.5 VA at both 50 Hz and 60 Hz. Operating times are symmetrical — 38... 57 ms for both AC and DC coil supplies — and arcing time runs 10... 20 ms. The coil termination uses screw-type terminals, which is the standard for this frame and avoids the need for special crimp tools on the control wiring.
Main contact ratings and switching frequency
The main contacts are configured as a 10-pole normally open set, with 2 auxiliary contacts. The contactor's switching frequency varies by duty class: up to 900 operations per hour in AC-1 (resistive), 850 in AC-3 (standard motor starting) and AC-3e, 350 in AC-2 (slip-ring motor), and 250 in AC-4 (plugging/inching). The AC-3 and AC-3e ratings are the ones that matter for most three-phase induction motor circuits — 850 ops/h is enough for frequent cycling on conveyors or pumps without derating the contactor. The AC-4 limit of 250 ops/h reflects the higher arc energy during reversing or inching duty.
Wire sizing and termination
The main circuit terminals accept solid conductors from 2.5 to 16 mm² and stranded conductors from 6 to 70 mm². Auxiliary contact terminals accept two conductors per clamp: 2x (0.5... 1.5 mm²) solid or stranded, or 2x (0.75... 2.5 mm²). That 70 mm² stranded capacity on the mains is generous for an S3 frame — it covers the full rated current without needing lug adapters. The screw terminals are the same type used across the SIRIUS S3 range, so panel builders can standardise termination tooling.
Environmental limits and mounting flexibility
The physical envelope is 140 mm high, 70 mm wide, and 195 mm deep — the depth is the dimension that typically governs gland-plate clearance in shallow enclosures.
Mechanical endurance and auxiliary contact ratings
The auxiliary contacts are rated for switching at various control voltages: 6 A at 24 V, 2 A at 48 V, 2 A at 60 V, and 1 A at 110 V. These ratings are for the auxiliary switch block integrated into the contactor, not a separate add-on module.