# Mechanism pressure-lockout interface Canonical URL: https://eloragrid.ai/symbols/mechanism-pressure-lockout-interface Publisher: Elora Grid Updated: 2026-11-03 Lookup label: MPI Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: switchgear Input: Pressure lockout contact Output: Blocked-operation state Carries the manufacturer's defined low-pressure blocking state to the command logic. ## In plain English ### What this block does Carries the manufacturer's defined low-pressure blocking state to the command logic. ### A simple example In a switchgear panel, a charging motor replenishes the mechanism after an operation. Supervisory contacts let the controller report an incomplete charge or repeated charging demand before an operator requests another operation. For this reference, the drawing identifies “Pressure lockout contact” at the input and “Blocked-operation state” at the output. Different operations may have different lockout conditions. ### What the drawings help you do Start at the named input: Pressure lockout contact. Identify its source device or document and the state represented on the drawing. Follow the named output: Blocked-operation state. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: Pressure lockout contact - Output: Blocked-operation state - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: Pressure lockout contact → MPI → Blocked-operation state A reading guide. The entry's original illustration and input/output facts describe this application. - [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7) ## What it represents Carries the manufacturer's defined low-pressure blocking state to the command logic. A stored-energy breaker mechanism has charging, release, indication and supervision functions. Motor supply, stored spring energy and the ability to complete an opening operation are separate drawing concerns. In a switchgear panel, a charging motor replenishes the mechanism after an operation. Supervisory contacts let the controller report an incomplete charge or repeated charging demand before an operator requests another operation. For this reference, the drawing identifies “Pressure lockout contact” at the input and “Blocked-operation state” at the output. Different operations may have different lockout conditions. Show the individual contacts and the relevant motor or release circuit. Supply voltage, charging time, operating duty and permissible alarms must follow the chosen mechanism documentation. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation. ## How to read it - Start at the named input: Pressure lockout contact. Identify its source device or document and the state represented on the drawing. - Follow the named output: Blocked-operation state. Cross-reference its destination and separate the command from confirmation that the equipment responded. - Different operations may have different lockout conditions. - Show the individual contacts and the relevant motor or release circuit. Supply voltage, charging time, operating duty and permissible alarms must follow the chosen mechanism documentation. ## Information to show or reference - Label the source and connection reference for pressure lockout contact. - Identify the destination and defined state of blocked-operation state. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: Different operations may have different lockout conditions. ## Important distinction Different operations may have different lockout conditions. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram. ## Facts - Representation: Functional block - Installation focus: Switchgear - Input / boundary: Pressure lockout contact - Output / connection: Blocked-operation state - Lookup label: MPI is a library lookup label, not a standard device designation. ## Public references - [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7) — Schneider Electric. Public technical context for stored-energy mechanism supervision. Breaker control, mechanism, position contacts, racking interlocks and test interfaces. The application text and educational graphic are independently authored; the publisher does not certify this representation. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.