The LV839231 is a Schneider Electric MX communicating opening voltage release designed for MasterPact MTZ drawout circuit breakers. It operates on a 380/480 V AC/DC control circuit and trips the breaker when voltage drops to between 0.7 and 1.1 times the rated control voltage (Un). The drawout mounting means it plugs into the breaker cradle — no hardwiring to the moving portion — so it's swapped without pulling the breaker itself.
This part is marked obsolete by the manufacturer. For a MasterPact MTZ drawout installation that needs an opening coil on a 380/480 V control bus, the LV839231 is the specific fit — but it's now in the surplus-and-broker channel.
Drawout mounting means the coil assembly slides into the MTZ cradle and connects via the breaker's own finger clusters. The 50 ms response time (±10%) is the same across MTZ1, MTZ2, and MTZ3 frames — no derating for frame size. Holding power is 4.5 VA / 4.5 W, so the control transformer or UPS supplying the trip circuit needs to budget that continuous draw per coil.