Product Overview

The 6EP1437-3BA00​ is a Siemens SITOP PSU400S stabilized switching power supply, delivering 24 V DC at 40 A (960 W) from a three-phase AC input of 400–500 V. It belongs to the SITOP PSU400S series — Siemens’ mid-to-high tier DIN-rail PSU line aimed at loads that exceed what a single-phase SITOP (PSU300S / SITOP Smart) can comfortably carry, but don’t yet justify the redundancy / ring-main architecture of SITOP PSU8600. The “400S” designation places it above the PSU300S (single-phase, narrower width) and below the PSU8600 (communicating, modular-bus) — a sweet spot for 24 V DC distribution in medium-sized control cabinets, multi-drive cubicles, and process skids where three-phase mains is already present and the 24 V load sits around 30–40 A continuous.Physically, the 6EP1437-3BA00​ is a 70 mm wide DIN-rail module (TH 35) with screw terminals on the AC input and DC output sides, an LED “DC OK” indicator, and a floating relay contact for “DC OK / Fault” signaling that can be picked up by the PLC’s DI card. Internally, the unit uses a three-phase active PFC front-end feeding a DC/DC stage with the usual SITOP protections: short-circuit, overload, over-temperature, and input surge. The output is stabilized ±1 % (static) with low ripple, and Siemens specifies “Extra Power” behavior — 120 % rated current continuously up to +45 °C ambient, and 150 % for 5 s (startup surges, capacitive loads). Another PSU400S hallmark is the shaped output characteristic that supports selective fuse tripping​ downstream: the PSU doesn’t fold back hard on overload the way a commodity switcher does, so the nearest miniature circuit breaker or fuse trips rather than the PSU itself going into latch-off — a feature that saves cabinet resets during commissioning.In the automation hierarchy, the 6EP1437-3BA00​ is the 24 V DC backbone. It feeds the SICOMP C30/C35 backplane supply (the +5 / +12 V actually comes from a SICOMP internal DC/DC, but the 24 V field side of a 6DS1723-8BB, plus the rack’s cooling fan, door lamp, etc.), or it feeds an S7-300/400/1500 rack’s PS module, or a LOGO! 24 V base, or a field of 24 V sensors, solenoids, and valve terminals. For panels where the 24 V load exceeds ~20 A (where a single-phase SITOP starts to derate or struggle on inrush), the three-phase 6EP1437-3BA00​ is the standard Siemens answer. The -3BA00 suffix specifically denotes the screw-terminal version; the -3BA10 is the push-in twin counterpart. Both are active Siemens catalog items (as of 2025, PSU400S is still current, unlike the SICOMP/LOGO! 0BA1 parts above), though lead times vary by region.One reseller pollution note before diving deeper: some listings tag the 6EP1437-3BA00 as “power supply input module” or conflate it with a “PM1207” / “SIMATIC PS307” — those are different animals. The 6EP1437-3BA00​ is a three-phase SITOP, not a SIMATIC rack PS (those are 6ES7307… or 6EP133x… single-phase). Keep that distinction clear when specifying spares.

Technical Specifications