The LA9FL4K4K is a mechanical interlock from the TeSys F range, designed to prevent simultaneous closure of up to three contactors mounted vertically. It physically blocks the armature of one contactor when another is engaged, which is the standard way to enforce source-transfer or reversing schemes without relying on control logic alone. It interlocks specific TeSys F contactor models: bottom position accepts LC1F500 2P/3P/4P or CR1F500 3P/4P, middle position accepts the same, and top position accepts LC1F630 3P/4P or LC1F800 3P. Mounting is fixed at 3 vertical — the interlock bar runs along the vertical axis, so the three contactors must be stacked in a column. This is a panel-layout constraint to account for before wiring.
Integration note
The interlock is a passive mechanical bracket and rod assembly — no wiring, no coil, no auxiliary contacts. It mounts between the contactors on the DIN-rail or panel plate. Verify the contactor stack order matches the interlock's position assignments (bottom, middle, top) before tightening the mounting screws. The interlock does not add any electrical burden; it only enforces mechanical exclusivity. If the application requires electrical interlocking as well (e.g., for remote diagnostics), add normally-closed auxiliary contacts from each contactor's own block into the opposite coil circuit.