The Siemens 3RT2037-3AC20 is a SIRIUS S2-frame power contactor rated for 65 A at 480 V in AC-3 duty — the motor-switching curve that governs most induction-motor loads up to that current. Spring-type terminals on the coil eliminate the torque check needed on screw-clamp variants; the contactor snaps onto 35 mm DIN rail per DIN EN 60715 or screws directly to a backplate.
Mounting and panel fit
The S2 frame footprint is 55 mm wide, 114 mm tall, and 130 mm deep. Clearance requirements: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm to the side. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the contactor sits in a swing-panel or angled subplate.
Switching performance and operating rates
Maximum operating frequency varies by duty: 800 cycles/hour for AC-1 resistive loads, 700 cycles/hour for AC-3 motor starting, and 200 cycles/hour for AC-4 plugging/reversing. Arcing time spans 10 to 20 ms; the main contactor is rated for 10 million mechanical operations typical.
Environmental limits and auxiliary contacts
Operates from -25 °C to +60 °C; storage range is -55 °C to +80 °C. The contactor includes an auxiliary switch with 1 NO + 1 NC configuration. Coil draws 0.36 A at 50 Hz and 0.39 A at 60 Hz at 24 V rated value.