MCCB for motor protection — 40 A, 3-pole, with undervoltage release
The Siemens 3VA2140-5MN32-0DA0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for motor protection, rated 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. Three poles, with an integrated undervoltage release (UVR) and phase failure detection built in. The interrupting capacity hits 187 kA at 240 V, 121 kA at 415/440 V, and still 75.6 kA at 500 V; at 690 V it holds 3.7 kA. That's a serious SCCR for a 40 A frame — suitable for high-fault industrial distribution.
What the ratings mean for fit
The 40 A rating holds flat from 40 °C to 70 °C ambient — no thermal derating curve to calculate for a warm panel. That's unusual for an MCCB; most frames start dialing back above 40 °C. The motor protection design means the thermal-magnetic trip curve is shaped for motor inrush, not just feeder protection. Phase failure detection is built in — no add-on module needed. The undervoltage release drops the breaker when control voltage falls below dropout, standard for safety circuits that need a loss-of-voltage trip. Interrupting capacity is the headline: 187 kA at 240 V means this breaker can be installed at the service entrance of a high-capacity transformer without worrying about cascading failure upstream. At 415/440 V it still delivers 121 kA — enough for most industrial main feeders. The 3.7 kA at 690 V is a reminder that this is a 40 A frame; for 690 V applications with higher fault current, step up to a larger frame.
Panel integration and dimensions
Mounts on a DIN rail or panel-mount via the 3VA2 frame. Dimensions: 105 mm wide, 181 mm high, 86 mm deep — fits standard MCCB cubicle cutouts. Power loss is 4.1 W maximum, negligible for thermal budgeting in a sealed enclosure. Operating range -25 °C to 70 °C, storage -40 °C to 80 °C.