Siemens VL 400 3VL9440‑7EE40 and 3VL4740‑2AA46‑0AA0 Moulded Case Circuit Breaker

The Siemens VL 400 series moulded case circuit breaker (MCCB) comprises the main breaker frame (3VL4740‑2AA46‑0AA0) and the auxiliary release (3VL9440‑7EE40). Together they provide a 400 A, 3‑pole, 600 V AC protection device with an electronic trip unit (ETU) featuring adjustable overload and short‑circuit parameters. This combination is designed for main switchboards, motor control centres, and feeder protection.

Main Breaker: 3VL4740‑2AA46‑0AA0

Rated current Iu = 400 A at 50/60 Hz. Rated operational voltage Ue = 690 V AC (UL/CSA: 600 V). Breaking capacity (Icu) = 65 kA at 415 V, 50 kA at 690 V. Number of poles: 3. The frame includes a built‑in electronic trip unit (ETU) with L (long‑time delay) and I (instantaneous) protection functions. The ETU is self‑powered from the line current, no auxiliary supply needed. Adjustable overload setting I_r = 0.4‑1 × Iu (160‑400 A). Short‑circuit pickup I_i adjustable from 2 to 12 × Iu (800‑4800 A). The breaker features a toggle handle with ON/OFF position indication and a padlockable mechanism.

Auxiliary Release: 3VL9440‑7EE40

This is an undervoltage release (UVR) that trips the breaker when the control voltage drops below 70% of nominal. It mounts inside the left auxiliary compartment of the VL400 frame. Nominal voltage 230‑240 V AC, 50/60 Hz. Pick‑up voltage >85% of U_n; drop‑out voltage<35% of U_n. It has a mechanically held latch, consuming 10 VA during steady state. This release allows remote tripping via a pushbutton or PLC output, and prevents automatic reclosure after power restoration without manual intervention.

Optional Accessories

The VL400 frame also accepts shunt trip (3VL9440‑6AE40), auxiliary contacts (1NO+1NC, 3VL9440‑1AE40), and alarm contacts. The breaker supports rotary handle operators (direct or extended) and motorised operators for remote control.

Environmental and Certifications

Operating temperature: ‑25 to +70 °C (derating above 50 °C). Storage: ‑40 to +85 °C. Protection degree IP20 (terminals IP00). The breaker complies with IEC 60947‑2, UL 489, CSA C22.2 No. 5. Two M5 terminal screws per pole accept copper cables up to 240 mm² or busbars. Dimensions (H×W×D): 210 × 140 × 110 mm. Weight approx. 2.5 kg.

Applications

Typically used as incoming main breaker for industrial panels, branch feeder protection for motors up to 200 HP at 480 V, and as a disconnect for PLC power supplies. The undervoltage release can be wired to an emergency stop circuit or a safety PLC to cut power when safety conditions are violated.