Siemens 3RT2045-1AC10 SIRIUS Power Contactor — 77 A at 480 V
The Siemens 3RT2045-1AC10 is a SIRIUS S3-frame power contactor rated for 77 A at 480 V in AC-3 duty — that's the motor-switching current, not the resistive load. The coil terminals are screw-type, and the main power circuit accepts solid conductors from 2.5 to 16 mm² or stranded from 6 to 70 mm² — that's a wide enough range to land a #4 AWG or a 2 AWG without adapters.
The S3 frame is 70 mm wide and 140 mm tall, with a depth of 152 mm — check your enclosure depth before committing.
Arcing time runs 10 to 20 ms at AC — that's the interval from contact separation to arc extinction. The contactor is rated for 1 000 operations per hour at AC-3 and AC-3e maximum, 900 at AC-1, 400 at AC-2, and 300 at AC-4. If your application cycles faster than that, you'll need to derate or step up to a larger frame. Mechanical life is typical 10 000 000 operations — that's the contactor body, not the contacts; electrical life depends on the switching current and load type.
Auxiliary Contacts and Control Circuit
Comes with an auxiliary switch block — the main contacts have a 10 to 2 configuration (10 NO, 2 NC). The auxiliary contact ratings at 24 VDC: 10 A; at 48 VDC: 2 A; at 60 VDC: 2 A; at 110 VDC: 1 A; at 125 VDC: 0.9 A; at 220 VDC: 0.3 A; at 400 VDC: 3 A; at 440 VDC: 0.8 A. These are the DC breaking limits — inductive loads will need a suppression diode across the coil to avoid contact welding.
The contactor is part of the SIRIUS family, which carries CE, UL, CSA, and IEC certifications as standard for the series. Specific compliance documentation (RoHS, REACH) is available on request with the RFQ.