SIRIUS S2 power contactor for motor loads
The Siemens 3RT1035-1AP60 is a SIRIUS S2-frame power contactor rated 22 kW at 500 V AC-3 and 18.5 kW at 400 V AC-2. That AC-3 duty rating is the one you care about for standard squirrel-cage motor starting — it tells you the contactor can make and break locked-rotor current without welding the main poles. AC-2 covers slip-ring motors where the inrush is lower but the switching cycle is more frequent. The screw-type main terminals accept stranded up to 25 mm² and solid up to 4 mm² per clamp. Coil draw at 24 V rated value is 10 A — that's the pick-up surge, not the hold-in; the sealed coil current will be lower. At 230 V rated value the auxiliary contacts handle 6 A.
The AC-3 rating of 22 kW at 500 V is the headline number for a sourcing decision: it means the contactor can switch a 22 kW motor on a 500 V three-phase line through its full load and break stall current. At 400 V the same contactor is rated 18.5 kW AC-2, so if your motor is 400 V and slip-ring, that's your limit. The AC-1 resistive rating is not listed here, but the 1 200 operations per hour maximum at AC-1 suggests it can handle higher resistive currents — just not at the same switching rate as motor duty. Electrical life depends on the load — at AC-3 the contactor is rated for 1 000 operations per hour, at AC-4 (plugging/inching) it drops to 300 per hour. That's fast enough for most line-starter applications but worth checking if you're sequencing contactors in a reversing or star-delta circuit.
Mounting and wiring in the panel
The 55 mm width and 112 mm height are standard S2 frame dimensions. Terminals are screw-type for the main circuit. The solid wire range is 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²), with a maximum of 2x (0.75 to 4 mm²) per clamp. That's generous for a 22 kW contactor — you can land 16 mm² or 25 mm² without a ferrule if the lug is rated for it.