The Siemens SITAS 4AM4042-5AJ10 is a 250VA control transformer that converts a 400V line-to-line supply to 110V at 2.27A for industrial control circuits. It is the go-to choice for European machinery panels where 110V control voltage is specified for contactors, relays, and auxiliary equipment powered from the 400V mains.

Voltage Adaptation

The primary features three taps at 380V, 400V, and 420V (±5%), allowing installation across varying European grid conditions. The 110V secondary is a widely adopted control voltage standard providing a safe, low-voltage level for operator interface components while maintaining sufficient power for coil-driven devices.

Performance & Build

Built on the EI 96/58 core at 89% efficiency, it delivers an 850VA short-time (S6) rating — over 3× the continuous rating — to handle high-inrush contactor and solenoid startup without voltage sag. The IP00 open-frame package (98×106×118mm) mounts via screws or 35mm DIN rail with screw-type or tab terminals.

Certifications

Certified to EN 61558-2-2 and EN 61558-2-6 as both a control and safety isolating transformer, with CE, cRUus (UL/CSA recognized), and EAC approvals.