Siemens 3RH2122-1BE40-ZW97 — Contactor Relay, Size S00
The Siemens 3RH2122-1BE40-ZW97 is a Size S00 contactor relay with two instantaneous normally-open contacts, designed for auxiliary switching in control panels. It mounts via screw or snap-on onto standard 35 mm DIN rail, fitting into the same footprint as the SIRIUS 3RT2 contactor family. Rated for a 60 V DC coil, the relay draws 4 W during both closing and holding, so the coil circuit sees a steady load — no inrush spike to size a power supply around. The operating temperature range of -25 to +60 °C covers most indoor panel environments, including unventilated enclosures near process lines. Switching capacity varies by voltage: at 24 V DC it handles 10 A, at 60 V DC it handles 4.7 A, and at 110 V DC it handles 3 A. The arcing time of 10 to 15 ms and the maximum operating frequency of 10 000 cycles per hour at AC (1 000 cycles per hour at DC-12 duty) give a clear picture of the relay's intended use — frequent switching in control logic, not heavy motor starting.
Mounting and Clearance
The relay snaps onto a 35 mm DIN rail per EN 60715 or can be screw-mounted. Clearance requirements: 10 mm upward, 10 mm forward, 10 mm downward, and 6 mm at the sides. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the panel layout forces an unconventional orientation. Dimensions are 45 mm wide, 58 mm high, and 73 mm deep — a compact footprint that leaves room for adjacent devices on the same DIN rail segment.
Wiring and Environmental Ratings
Terminals accept solid or stranded wire: 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or 2× 4 mm². Pollution degree 3 means the relay is rated for industrial environments where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation may occur — typical for control panels not in a climate-controlled room. Storage temperature spans -55 to +80 °C, which exceeds the operating range — that limit governs handling and warehousing, not running conditions. Relative humidity minimum is 10 %, and the part complies with RoHS substance prohibitions effective October 1, 2009. Surge voltage resistance is rated at 6 kV, giving confidence that the relay withstands switching transients common in industrial power distribution without flashover.