The LA9FL4F4F is a mechanical interlock accessory from the TeSys F range, designed to key three contactors vertically so only one can close at a time. It prevents simultaneous closure — critical for reversing drives, star-delta transitions, or any circuit where two contactors energizing together creates a phase-to-phase short. Mounts in a 3-vertical stack. The interlock ties the bottom contactor (LC1F115 through LC1F150 or CR1F150, 3P or 4P), the middle contactor (same range), and the top contactor (LC1F630 or LC1F800 3P, or CR1F630 3P or 4P). That covers the full TeSys F frame from 115 A up to 800 A.
Integration note
This is a purely mechanical interlock — no electrical connections, no auxiliary contacts. It clips onto the contactor fronts and uses a sliding bar to block the other armatures when one pulls in. The 3-vertical stack eats the same DIN-rail footprint as the contactors themselves; no extra panel width needed, just height. For a 3-contactor star-delta starter on a 250 kW motor, this interlock guarantees the star and delta contactors never overlap. The mechanical tie is faster than any electrical interlock relay and doesn't fail if a coil supply drops.
No direct replacement exists because none is needed — this is the current mechanical interlock for the TeSys F contactor family. If you're maintaining a panel built around LC1F contactors, this is the factory-specified interlock.