The Schneider Electric LV839238 is an MX opening voltage release — a shunt trip coil — designed for MasterPact MTZ drawout circuit breakers. It sits inside the breaker's control compartment and, when energized, mechanically trips the breaker open. The drawout mounting means it installs into the breaker cradle, not the fixed panel wiring, so it travels with the breaker cassette during racking.
That dual AC/DC rating simplifies panel design — one coil covers both supply types without a separate rectifier. The tripping threshold is 0.7 to 1.1 times the nominal control voltage, so on a 480 V system the coil will reliably trip anywhere from 336 V to 528 V. Holding power is 4.5 VA or 4.5 W, a modest draw that a standard control transformer can supply.
Response time and application context
The response time is 50 ms ± 10 % across the MTZ1, MTZ2, and MTZ3 frame sizes. That 50 ms window is the time from energizing the coil to the breaker contacts starting to open — fast enough for emergency-stop and shunt-trip functions where you need the breaker open before a downstream fault can escalate. In a drawout cradle, the coil's wiring connects through the breaker's secondary disconnects, so the control circuit stays intact during racking.