What it is and what the ratings mean
The Siemens SIRIUS 3RT1024-1AP00-ZW98 is a size S0 power contactor with three normally open main contacts, designed for switching motor loads and resistive loads in industrial control panels. The 45 mm width and screw-and-snap-on mounting onto 35 mm DIN rail per DIN EN 50022 mean it fits standard panel layouts with a 6 mm side clearance required for heat dissipation. The IP20 front enclosure protects against finger contact during operation, while the terminals themselves are IP00 — meaning the wiring compartment is open to the panel environment, which is typical for contactors mounted inside a cabinet. The 24 VDC coil draws the listed holding current; the dropout threshold is below 18 V, so verify your control supply stays above that during brownout conditions. The AC-2 rating at 400 V is 5.5 kW, which covers slip-ring motor switching where the load current stays relatively constant during start. The AC-4 rating at 400 V is 12.5 A, the figure that governs reversing or inching duty — that is the current the contactor can break under the hardest motor-switching conditions. For resistive loads (AC-12) the maximum operating current is 10 A. The mechanical life is rated at 10 million operations typical, so in a moderate-duty cycle this contactor will outlast the panel. The rated operational voltage covers 230 V at 50 Hz up to 690 V, with a motor rating of 7.5 kW at both 500 V and 690 V. The operating temperature range is -25 to +60 °C, and the maximum altitude is 2 000 m without derating. Pollution degree 3 means it is suitable for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation.
Integration and wiring
The screw-type terminals for the main current circuit accept solid conductors from 2x (0.5 to 1.5 mm²) up to max 2x (0.75 to 4 mm²), and stranded conductors from 2x (1 to 2.5 mm²) up to max 2x 10 mm². AWG equivalents are 2x (16 to 12) solid and 2x (14 to 10) stranded, with a single 8 AWG maximum. For type 2 coordination (no damage to the contactor under short circuit), use a gL/gG fuse rated 25 A; for type 1 coordination (contactor may need replacement after fault), the fuse can be 63 A. The contactor is designed for side-by-side mounting with zero clearance between units, so you can pack multiple contactors on the same DIN rail without derating — just respect the 6 mm side clearance to adjacent components if the manufacturer's spacing rule applies.