The Schneider Electric LV839269 is an MN diagnostic undervoltage release designed for MasterPact MTZ drawout circuit breakers. It operates on a 380/480 V AC 50/60 Hz or 380/480 V DC control circuit, with a threshold tripping voltage of 0.35 to 0.7 Un on opening and 0.85 Un on closing. The device is classified as a communicating control type with a drawout mounting mode, and it serves a safety device application by signaling an error when the coil is powered and the MN is open.
The 380/480 V AC/DC control circuit voltage covers common industrial supply voltages across both AC and DC systems, so the release works in panels fed from a 400 V three-phase line or a 380 V DC bus. The threshold tripping voltage of 0.35 to 0.7 Un on opening means the release will drop out and signal a fault when the control voltage falls below roughly 133 V (at 380 V nominal) to 336 V (at 480 V nominal), protecting downstream equipment from undervoltage conditions. The 4.5 VA / 4.5 W holding power is low enough that the control transformer sizing is rarely a constraint — standard 50 VA control transformers handle multiple such releases without issue.
Deployment Context
As a drawout-mounted undervoltage release for MasterPact MTZ breakers, this part is installed in the breaker's accessory compartment and wired to the control circuit. The drawout form factor means it can be inserted or removed without powering down the main bus — useful for retrofit or maintenance on live switchgear. The safety device application (signaling an error when the coil is powered and the MN is open) makes it part of the breaker's undervoltage protection scheme, typically used in motor control centers or distribution panels where a voltage dip must trip the main breaker and alert the control system.