What this SIRIUS Size S3 contactor does
It carries a 45 kW rating at 500 V AC-3, which is the standard duty for squirrel-cage motors — that's the number that matters for sizing a motor starter. At 690 V AC-3 it's rated 21.1 kW, so the same contactor can handle a higher-voltage motor at reduced power. At 70 mm wide and 146 mm tall, it fits a standard 8-module DIN-rail slot — no surprises for the panel builder laying out a row of starters. Termination is screw-type on the main current circuit, accepting solid conductors up to 4 mm² on the control side and stranded up to 50 mm² on the power side. That covers most motor feeds up to 45 kW without needing lug adapters.
Duty cycle and thermal limits
The electrical endurance depends on the duty category: AC-3 allows up to 1,000 switching cycles per hour, while AC-4 (plugging/inching) drops to 300 cycles per hour. For resistive loads (AC-1) it's 900 cycles per hour. The front is IP20 with the cover/box terminal installed; the terminal area itself is IP00, so live parts are exposed when the panel door is open.
The coil operates on 50/60 Hz with a voltage tolerance of 0.8 to 1.1 times rated at 50 Hz and 0.85 to 1.1 at 60 Hz. That's a standard ±20% / +10% range — the coil will pick up reliably even if the control transformer sags under load. The contactor is rated for 24 V DC auxiliary switching at 10 A, stepping down to 0.3 A at 220 V DC. That covers most PLC output cards and relay interfaces. For AC auxiliary loads at 230 V it's rated 6 A, and at 400 V it's 3 A.