The Siemens SENTRON 3VA2440-5MN32-0AE0 is a 3-pole molded case circuit breaker (MCCB) designed specifically for motor protection, with a continuous current rating of 400 A that holds flat across the full 40 °C to 70 °C ambient range — no derating needed as the panel warms up. Interrupting capacity reaches 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 9 kA at 690 V — so the SCCR headroom is there for high-fault industrial feeds, but verify the 690 V number against your transformer secondary if that's your service voltage.
Maximum power loss is 63.5 W; account for that heat in the enclosure sizing if the breaker is running near its 400 A continuous rating inside a sealed cabinet.