The Siemens 3RT2036-3KB44-3MA0 is a SIRIUS coupling contactor in the S2 frame size, designed for applications where a main contactor needs to be electrically isolated from the control circuit — typically used to switch loads like motors or heaters in a panel while keeping the coil circuit separate for safety or logic reasons. Spring-type terminals (cage clamp) on the magnet coil and main contacts accept 2x (0.5... 2.5 mm²) solid or stranded, which matches standard control wiring practice and eliminates the need for ferrule tightening checks during commissioning. The contactor measures 55 mm wide by 114 mm high by 178 mm deep, and mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 60715. Main contacts rated for 18 A operational current in AC-3 duty, with 1 A minimum switching capability. Switching frequency: 1 000 cycles/h at AC-1, 800 at AC-3, 600 at AC-2, 250 at AC-4.
Auxiliary contact ratings — what the voltage/current table tells you
This contactor variant ships without an auxiliary switch block (auxiliary switch: no), but the auxiliary contact ratings are listed for when a block is added. At 24 V rated value, the auxiliary contacts carry 6 A; at 48 V, 2 A; at 60 V, 2 A; at 110 V, 1 A; at 125 V, 0.9 A; at 220 V, 0.3 A; at 400 V, 3 A; at 440 V, 0.6 A. The 230 V rating is given as 10 hp, which is a motor load rating for the auxiliary contacts — unusual for auxiliaries, so verify the application before using them for motor switching. The 400 V 3 A rating is notable: it suggests the auxiliary contacts can handle a moderate inductive load at line voltage, useful for piloting another contactor coil.