The Siemens 3RT1016-1AD01 is a SIRIUS S00 power contactor — the smallest frame in the SIRIUS family, sized for motor loads up to 5.5 kW at 690 V. The 45 mm width keeps the rail density tight; three of these fit in the same space a single 3RT1036 frame occupies.
The contactor is rated for AC-2 duty at 400 V (4 kW) and AC-4 at 400 V (8.5 A), so it handles both slip-ring motor starting and plugging/reversing cycles. For resistive loads (AC-12), it carries 10 A continuous. Coordination is straightforward: Type 2 coordination requires a 20 A gL/gG fuse; Type 1 allows up to 35 A gL/gG. That gives the panel builder a clear fuse choice without over-sizing the feeder.
Screw 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 or stranded. AWG equivalents are 2x (20 to 16), 2x (18 to 14), or 1x 12. The IP20 finger-safe front cover stays on during wiring; side clearance is only 6 mm for side-by-side mounting, so you can pack them tight on the rail.