What it is and what the ratings mean
The Siemens 3RT2037-3AL20-Z W96 is a size S2 power contactor from the SIRIUS 3RT2 series, built for switching three-phase motor loads in industrial control panels. Its AC-3e/AC-3 rating of 65 A and 30 kW at 400 V means it is sized for a 30 kW induction motor on a 400 V line — the AC-3 duty class covers starting and disconnecting squirrel-cage motors under full load, which is the standard for most conveyor, pump, and fan applications. The 230 V AC 50/60 Hz coil is a common control voltage in European panels; the built-in 1 NO + 1 NC auxiliary contact set handles feedback or interlocking without an extra block. Termination is split: screw terminals on the main circuit for high-current power wiring, spring-loaded terminals on the control and auxiliary circuit for faster, vibration-resistant wiring of the coil and aux contacts. This combination is typical on Siemens S2 contactors — the spring-cage side saves time on control wiring while the power side keeps the torque security of screw clamps.
Sourcing and lifecycle reality
RoHS compliance is confirmed since October 2014, and REACH candidate-list information is available from Siemens. No special export restrictions apply (AL: N / ECCN: N).
Where it fits in the panel
The S2 frame size mounts on a standard DIN rail (EN 60715) and occupies roughly 55 mm width by 114 mm height by 130 mm depth. The multi-unit packaging variant (pack of 15) suggests it is also stocked in bulk for panel builders running multiple identical motor starters. The spring-loaded control terminals accept ferruled stranded wire up to 2.5 mm²; strip length is 8–10 mm for reliable cage clamping.