The LA9FL4L4H is a mechanical interlock accessory in the TeSys F range, designed to prevent two contactors from closing simultaneously. It physically blocks one contactor's armature when the other is engaged, which is essential for reversing drives, star-delta starters, or any circuit where simultaneous closure would create a phase-to-phase short.
Which Contactors It Fits
This interlock mounts in a 3-vertical configuration and accepts a specific stack: bottom position takes LC1F265 through LC1F330 or CR1F265 through CR1F330 (3 or 4 pole); top position takes LC1F630 or LC1F800 (3 or 4 pole) or CR1F630 (3 or 4 pole); middle position takes LC1F630 or LC1F800 (3 pole) or CR1F630 (3 or 4 pole). That means a single LA9FL4L4H can handle a mixed pair of frame sizes — for example, a smaller bottom contactor and a larger top unit — which is common in reduced-voltage starting schemes where the main and bypass contactors differ in rating.