The Siemens 3RT1535-1AC20 is a Size S2 SIRIUS power contactor. It carries 40 A per NO and per NC contact in the main circuit, with a 6 kV rated impulse withstand voltage for the main and auxiliary circuits. The coil pulls 24 V at both 50 and 60 Hz, drawing 15 VA at 50 Hz. Screw-type terminals on both the main and auxiliary/control circuits make for straightforward wiring in the panel.
The mounting surface can be vertical, with the contactor rotatable ±180° and tiltable ±30° front-to-back. Side-by-side mounting is allowed, with a 6 mm gap specified at the side. Dimensions: 112 mm high, 73 mm wide, 115 mm deep.
Wire range and terminal capacity
Main circuit terminals accept stranded wire from 2x (0.75 to 25 mm²) and AWG 2x (18 to 2). Solid or stranded auxiliary/control terminals accept 2x (0.5 to 1.5 mm²) and 2x (0.75 to 2.5 mm²), with a maximum of 2x (0.75 to 4 mm²). That covers most panel wiring from small signal to motor power leads.
Auxiliary contacts are rated for switching: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, 3 A at 400 V, and 1 A at 440 V. That covers control voltages commonly found in industrial panels.