Siemens 3RT1035-1QB44-3MA0 Three-Pole Contactor

Siemens 3RT1035-1QB44-3MA0 is a Sirius power contactor, three-pole, intended for AC-3 motor-control duty. In a size S2 frame with screw-terminal main connections, it combines three main normally open contacts with a 24 V DC coil. The coil controls the main circuit rated for up to 40 A and up to 18.5 kW at 400 V, suitable for initiating and stopping three-phase motors such as pumps, fans, and conveyors. The auxiliary circuit offers two normally open and two normally closed contacts (2 NO + 2 NC), enabling interlocking and signaling alongside the main contacts. The unit is engineered for industrial environments, with an operating temperature range of -25 to +60 C and installation altitude up to 2,000 m. Mechanical service life is typically around 10 million switching cycles, reflecting Siemens’ emphasis on durability in automation panels. This contactor is part of the Sirius 3RT family, and is commonly used in control panels for motor-starters, with compatibility for integration with protective devices and supplementary accessories to form complete motor-control solutions.