MX opening voltage release for MasterPact MTZ1 drawout
The Schneider Electric LV833809 is an MX opening voltage release from the MasterPact range, designed as a standard control accessory for MasterPact MTZ1 drawout circuit breakers. It operates on a 12 VDC power supply and consumes 4.5 W in the holding state. When the supply voltage drops to between 0.7 and 1.1 times the rated Un, the coil trips the breaker open. Maximum response time on an MTZ1 frame is 60 ms — fast enough for emergency-stop circuits that need the main breaker to drop before downstream contactors open. This is a drawout-specific variant; the release mounts into the breaker cradle, not the fixed portion of the switchgear. If your installation uses a fixed-mounted MTZ1, the order code differs.
The 12 VDC supply is the coil voltage, not the breaker's main power. The release draws 4.5 W holding power — a standard 24 VDC control transformer with a 12 VDC step-down regulator can drive it, but verify the regulator's continuous current rating against the inrush at pickup. The 0.7...1.1 Un trip threshold means the release will open the breaker if the control voltage sags below about 8.4 VDC (0.7 × 12 V) or rises above 13.2 VDC (1.1 × 12 V). This undervoltage-release behavior is typical for an MX coil — it is not a shunt trip that fires on a pulse; it holds the breaker closed only while the control voltage stays within that band. The 60 ms maximum response time applies to the MTZ1 frame only. On older MasterPact frames (NT, NW) the same MX coil may respond differently; the spec is tied to the breaker mechanism, not the coil alone.