The Siemens 3RT2028-1BJ80 is a SIRIUS S0-size power contactor with a 24 VDC coil and screw-type terminals, designed for snap-on mounting onto 35 mm DIN rail per DIN EN 60715. The S0 frame — 85 mm high, 45 mm wide, 107 mm deep — fits standard panel layouts and leaves clearance for wiring: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the side.
Duty-cycle and switching-frequency limits
Maximum switching frequency depends on the load category: 1 000 cycles/h for AC-1 resistive loads, 750 cycles/h for AC-2 and AC-3 motor duty, and 250 cycles/h for AC-4 plugging/inching duty. The AC-3e rating also caps at 750 cycles/h, matching the standard AC-3 figure for energy-efficient motor applications.
DC-13 breaking capacity across the control voltage range
For DC-13 solenoid loads, the contactor breaks 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V — covering the common control-circuit voltages found in North American and European panels.