The Siemens SENTRON 3VA9277-0HC10 is a synchronizable motor operator with a stored-energy mechanism (SEO) designed as an accessory for 3VA6 150/250 and 3VA5 250 molded-case circuit breakers. It provides remote electrical charging and closing of the breaker mechanism, which means it can reclose after a trip or cycle the breaker for routine switching without an operator at the panel. The stored-energy design charges a spring over roughly 0.08 s (typical make and break time), then releases it to close the breaker contacts at a consistent speed independent of the operator's hand speed — important for maintaining the breaker's short-circuit interruption ratings. Rated for 24 V DC control voltage with an operating apparent power of 300 VA, this unit draws that power only during the charging cycle; once the spring is stored, the coil drops to a holding current.
The motor operator mounts directly onto the breaker face — it is not a DIN-rail component. The overall dimensions (118.7 mm height, 105 mm width, 162.8 mm depth) include the mechanism projecting forward from the breaker front. That 162.8 mm depth is the critical dimension for enclosure depth clearance: verify the panel door clearance before specifying, especially in shallow enclosures or those with a secondary inner door. The 7 mm stripped length on the control wiring terminals is standard for ferrule termination.