The Siemens 3VA1150-6EF32-0AH0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated 50 A continuous at 40 °C, with a thermal-magnetic TM240 release tuned for line protection.
Rated current holds at 50 A from 40 °C up to 50 °C, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C — so in a warm enclosure you lose about 10 % by the time you hit 70 °C ambient. Breaking capacity drops sharply with voltage: 220 kA at 240 V, 154 kA at 415 V, 121 kA at 440 V, and 17 kA at both 500 V and 690 V.
The TM240 release is non-interchangeable, so verify your continuous load is at or below 50 A before committing the BOM line. Maximum power loss is 14.6 W, which matters for thermal budgeting in sealed enclosures.