Integrator's note on the 3RT2037-1NE30
Its coil accepts 48 to 80 V AC or DC, with pickup guaranteed at 80 % of rated voltage. Switching frequency depends on duty: 800 cycles/hour for resistive loads (AC-1), 700 for motor starting (AC-3 and AC-3e), 400 for slip-ring motor reversing (AC-2), and 200 for plugging or inching (AC-4).
Auxiliary contact configuration and ratings
The contactor carries an auxiliary switch block (1 NO + 1 NC, per the 18-to-1 main contact count notation). The auxiliary contacts are rated: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, and 0.3 A at 220 V — all presumably AC/DC depending on the circuit. These are sufficient for signaling back to a PLC input or driving a small indicator lamp, but not for switching a contactor coil directly at higher voltages without checking the making/breaking capacity.
Termination and environmental limits
Coil terminals are screw-type, accepting 2 × (0.5 to 1.5 mm²) or 2 × (0.75 to 2.5 mm²) solid or stranded wire. The contactor fits a standard S2 footprint: 55 mm wide, 130 mm deep, 114 mm high.