Siemens SENTRON 3VA2140-5MN36-0AB0 — 40 A MCCB for Motor Protection
Motor Protection and Phase Failure Detection
This MCCB is built for motor protection duty, with integrated phase failure detection. That means it will trip if one phase drops out — a common failure mode that can single-phase a motor and burn it out if the overload relay doesn't catch it fast enough. The design eliminates the need for a separate phase-failure relay in the motor branch circuit, saving a DIN-rail slot and a wiring step. The basic switch is order code 3VA21405MN360AA0, and the auxiliary switch configuration is two HP-style aux switches, which can be wired for remote status indication or interlocking.
The interrupting ratings are given at five voltage levels: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V (–). The sharp drop at 690 V is typical for a 40 A frame — the arc energy at that voltage exceeds what the compact arc chutes can extinguish at high current. For a 400 V distribution system, the 121 kA rating covers most industrial transformer sizes up to about 2.5 MVA. The minimum trip time is 4 s, maximum 17 s, which is a thermal-magnetic or electronic trip curve suited for motor starting inrush without nuisance tripping.
No undervoltage release, no voltage trip, no communication module, and no ground-fault monitoring are built in; if those functions are needed, they must be added via external accessories or a different variant.