The Siemens 3RT1024-3AB00 is a SIRIUS S0-frame power contactor with three normally-open main contacts and no NC main contacts. It is rated for motor switching at 7.5 kW on 500 V and 690 V supplies, with an AC-4 rating of 12.5 A at 400 V for reversing or inching duty and an AC-2 rating of 5.5 kW at 400 V for slip-ring motor applications.
The 7.5 kW rating at both 500 V and 690 V tells you this contactor handles a 3-phase motor load up to that power at those line voltages — the same power at a higher voltage means lower current, so the thermal capacity of the S0 frame is the limiting factor, not the voltage. The AC-4 rating of 12.5 A at 400 V is the figure to watch for plugging or jogging applications where the contactor makes and breaks stalled-rotor current; that duty cycle generates more arc energy than AC-3, so the 12.5 A limit governs there. Screw terminals on the main circuit accept 2x (0.25...2.5 mm²) solid or 2x (1...2.5 mm²) stranded, up to 2x 10 mm² maximum — standard for a 45 mm contactor in a control panel. Type 2 coordination (for motor starter applications) requires a 25 A gL/gG fuse; Type 1 coordination allows a 63 A gL/gG fuse. The auxiliary contact ratings cover 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V DC — enough for PLC-level signal switching or relay interposing.