77 A at 480 V — what that means for motor loads
The 3RT2045-1AB00-1AA0 is a SIRIUS power contactor, Size S3, rated 77 A at 480 V in AC-3 duty — that's the motor-switching category per IEC 60947-4-1, so it handles the inrush of a squirrel-cage motor up to that current and makes/breaks the load under running conditions. At 230 V the same contactor is rated 15 hp, which lines up with typical NEMA motor frame assignments for that voltage class. Switching rate for AC-3 duty is 1,000 operations per hour maximum — that's the thermal limit of the arc chamber, not the coil; if your application cycles faster, you'll need to step up to a larger frame or a dedicated switching contactor.
Standing position on a horizontal surface is the specified orientation; the contactor is 70 mm wide, 140 mm tall, 152 mm deep, so budget for the depth when laying out the gland plate. Main circuit wiring accepts solid 2.5–16 mm² or stranded 6–70 mm².
Auxiliary contacts and coil ratings
Built-in auxiliary switch (1 NO + 2 NC main contacts per the 10...2 configuration) — no separate add-on block needed for basic feedback to the PLC. Arcing time is 10–20 ms, and the operate/release times at AC are 10–21 ms — fast enough for most motor control schemes but not for precision synchronisation; if you need contact closure within a few ms of a signal, add a fast-acting relay.
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