The Siemens 3VA9277-0HC30 is a SENTRON motorized operating mechanism with stored energy mechanism (SEO) — an accessory purpose-built for remote electrical switching of 3VA6 150/250 and 3VA5 250 molded-case circuit breakers. It accepts a control supply of 110–230 V AC (60 Hz) or 110–250 V DC, drawing 300 VA apparent power during operation. The stored-energy design means the mechanism charges a spring, then releases it to close or open the breaker contacts in a consistent, fast make/break time of 0.08 s (typical) regardless of how slowly the control signal arrives — critical for synchronizing breaker operations in a distribution panel.
The 3VA9277-0HC30 mounts directly onto the 3VA6 or 3VA5 breaker frame, adding 105 mm width and 162.8 mm depth to the assembly — important to check against your enclosure depth and sidewall clearance before specifying. Height is 118.7 mm. Wiring terminations accept conductors with a 7 mm stripped length.