Siemens 4AM3442-5AV00 400V to 42V 100VA Single-Phase Control Transformer

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Product Specifications

Brand: Siemens

Part Number: 4AM3442-5AV00-0EA0

Product Type: Single-Phase Control / Safety Isolating Transformer

Series: SITAS 4AM3442

Rated Power: 100 VA

Primary Voltage: 400 V ±5% (380/400/420 V taps)

Secondary Voltage: 42 V

Secondary Current: 2.38 A

Short-Time Power (S6): 310 VA

Frequency: 50/60 Hz

Product Description

The 4AM3442-5AV00 is a 100VA single-phase control transformer from the Siemens SITAS 4AM series, delivering 42VAC at 2.38A from a standard 400V three-phase panel supply. It fills the gap between 24V control circuits and full 230V mains, providing SELV-compliant power with higher voltage headroom than 24V systems.

Why 42V

At 42VAC, the secondary stays below the 50VAC SELV (Safety Extra-Low Voltage) threshold defined in IEC 60364-4-41, permitting simplified wiring and reduced shock-risk precautions compared to mains-voltage control circuits. This voltage level appears in confined-space portable tool supplies, older machine tool auxiliary circuits built to superseded national standards, and specialist industrial equipment where 24V cannot overcome cable voltage drop over long control runs.

Construction and Certification

The EI 84/42 laminated core with Class B insulation achieves 86% efficiency at 40°C ambient. The 310VA S6 short-time rating handles contactor and relay inrush currents without voltage sag. IP00 open-style construction mounts via screws or 35mm DIN rail (EN 60715), with screw-type terminals. Certified to EN 61558-2-2 and EN 61558-2-6 with CE, cRUus, and EAC approvals.

Key Decision Parameters

Parameter	Value
Rated Power (Continuous)	100 VA
Short-Time Power (S6)	310 VA
Primary Voltage	400 V ±5% (380/400/420 V taps)
Secondary Voltage	42 V
Secondary Current	2.38 A
Frequency	50/60 Hz
Efficiency	86%
Insulation Class	Class B (40°C ambient)