The LV839240 is a second MX opening coil — a voltage release that trips a MasterPact MTZ breaker when control voltage is applied or removed, depending on the circuit design. It mounts in the drawout cradle of MTZ1, MTZ2, or MTZ3 frames, so the coil stays with the chassis while the breaker slides in and out for maintenance. Control voltage is 24 V AC 50/60 Hz or 24...30 V DC, with a holding draw of 4.5 VA or 4.5 W once energized. Response time is 50 ms ±10 % across all three MTZ frame sizes, so the trip delay is consistent regardless of which breaker frame it's paired with.
What the drawout mounting means for your panel
Drawout mounting means the coil is fixed in the breaker cradle, not on the moving breaker itself. When you rack the MTZ breaker out for inspection or swap, the MX coil stays wired to the control circuit — no need to disconnect flying leads. This is standard for MasterPact drawout gear; if your installation is fixed-mounted (non-drawout), this part will not fit without the cradle assembly.