The Siemens SITAS 4AM4042-4TT10 is a 250VA 1:1 single-phase isolation transformer that provides galvanic separation between a 230V primary supply and a 230V secondary load at 1.09A. It is the essential solution for breaking ground loops, suppressing line-conducted noise, and protecting sensitive equipment in industrial control panels.

Why Isolation Matters

Unlike a direct mains connection, the 1:1 isolation transformer decouples the load from supply-side disturbances. This is critical for measurement circuits, PLC I/O banks, and communication equipment where common-mode noise can cause data errors or component stress. The II0 vector group (no shielding winding) provides fundamental isolation per EN 61558-2-4.

Performance & Construction

Built on the EI 96/58 laminated core with 89% efficiency, it handles 850VA short-time (S6) loads for momentary inrush. Primary taps at 218V, 230V, and 242V allow compensation for site voltage variations. The IP00 open-frame package measures 98×106×118mm and mounts on screws or 35mm DIN rail.

Certifications

CE, cRUus (UL/CSA recognized), and EAC certified. Compliant with EN 61558-2-1, EN 61558-2-2, and EN 61558-2-4. Class B insulation, 40°C ambient rated.