The 3RT1045-1AG20: Rated at 45 kW at 500 V and 21.1 kW at 690 V in AC-3 duty, this contactor handles the full-load current of a three-phase induction motor within those power bands. The screw-type terminals on the main current circuit accept solid conductors from 0.5 mm² up to 4 mm² (two per clamp) and stranded conductors up to 50 mm², which covers the range from control wiring through to the motor feeder cable for a 45 kW load.
Environmental and Protection Ratings
The front of the contactor carries IP20 protection with the cover or box terminal fitted, meaning it is finger-safe from the front once installed in a panel. The terminal area itself is rated IP00, so the contactor must live inside an enclosure that provides the overall panel ingress rating.
Switching Performance and Mechanical Life
Mechanical life is rated at 10 million operations typical, which for a motor-starting application at 1000 operations per hour (AC-3 maximum) translates to over 10,000 hours of continuous cycling before the contactor wears out mechanically. The arcing time sits between 10 and 15 ms, and the total opening time at AC is 10 to 25 ms — fast enough to clear faults in coordination with upstream motor circuit protectors. Maximum operating frequency varies by duty: 900 cycles/hour in AC-1 resistive loads, 1000 cycles/hour in AC-3 motor starting, and 300 cycles/hour in AC-4 plugging or inching duty. If your application involves frequent reversing or jogging, the AC-4 limit is the one that governs contactor life.
The auxiliary contact block (integrated or add-on) carries 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. These ratings are for the control circuit — feeding the contactor coil, PLC inputs, or status lamps. At 220 V the rating drops to 0.3 A, so if you are switching a 220 V control transformer, verify the inrush does not exceed that figure.