The Siemens 3VA9277-0HC15 is a SENTRON motorized operating mechanism with stored energy (SEO) designed for remote switching of 3VA6 150/250 and 3VA5 250 molded-case circuit breakers. It draws 24 V DC and has a typical make/break time of 0.08 s, pulling 300 VA during operation. This is a panel-mount accessory — it bolts onto the breaker front, not a standalone device — and the 162.8 mm depth, 105 mm width, 118.7 mm height footprint fits within the standard SENTRON family envelope. The stored-energy mechanism means the spring charges then fires the contacts, giving consistent switching speed independent of operator or coil timing.
The 300 VA operating apparent power at 24 V DC is the peak inrush when the motor charges the spring — about 12.5 A at nominal voltage. The control transformer or DC supply feeding this mechanism must handle that surge, not just the holding current after the spring is charged. The 0.08 s make/break time is the mechanical switching interval, not the arc extinction time; the breaker itself handles interruption. The 7 mm stripped length on the control wiring terminals is the standard SENTRON accessory pitch — use ferruled stranded 0.2–2.5 mm² for reliable connection.
Deployment context
Mounts directly onto the front of a 3VA6 or 3VA5 breaker in a panel enclosure. The mechanism adds depth to the breaker assembly, so verify the enclosure depth clearance (162.8 mm plus the breaker body) before specifying. The 24 V DC control signal is typically run from a PLC digital output or a dedicated relay — no separate power supply required if the panel already has a 24 V bus.