The Siemens 3RT1045-1AK60-ZW96 is a SIRIUS S3 power contactor sized for motor loads up to 45 kW at 500 V AC-3 and 21.1 kW at 690 V AC-3, making it the right fit for a 500 V distribution system driving a medium induction motor — a common pairing in industrial panels where the line voltage sits above the standard 400 V. Screw-type terminals accept solid conductors up to 4 mm² and stranded up to 50 mm².
Duty-cycle and switching frequency
Maximum switching frequency varies by duty class: 1 000 operations per hour at AC-3 (the motor-starting rating that governs most conveyor and pump applications), 900 at AC-1 (resistive loads like heaters), 400 at AC-2 (slip-ring motor starting), and 300 at AC-4 (plugging or inching). For a motor starter that cycles once per minute, the AC-3 limit of 1 000 ops/h leaves headroom; a reversing starter that jogs several times a minute pushes toward the AC-4 ceiling of 300 ops/h, so the application profile matters for contactor life.
Front-side protection is IP20 with the cover or box terminal installed; the terminal itself is IP00, so the panel builder must ensure that live screw terminals are not accessible during operation — standard practice for a motor starter in a locked enclosure.