The LA9FG4G4F is a mechanical interlock from the TeSys F range, designed to prevent simultaneous closure of three vertically mounted contactors or reversing contactors. It physically blocks the armature of one device from engaging while another is closed, which is critical for motor reversing circuits or any application where two contactors must never be energized at the same time. It interlocks bottom-position LC1F115 through LC1F150 3P or 4P contactors (and CR1F150 equivalents) with top-position LC1F185 through LC1F225 3P or 4P units (and CR1F185 equivalents), plus a middle position for the larger frame. Mounting is specified as three vertical, which is the standard orientation for a three-contactor reversing or star-delta group in a control panel. The mechanical linkage is a passive device — no wiring, no coil, just a bracket and rod assembly that transfers the blocking force between the contactor yokes.
It is classified under the 18402-WORLD SERVICE PARTS (CONTROL ACCESS) category, which typically means it is stocked as a serviceable accessory for installed TeSys F installations.
Integration Notes
The interlock mounts between the contactors on a DIN rail or backplate. The three vertical positions are fixed: the bottom position takes the smaller frame (115–150 A), the top and middle positions take the larger frame (185–225 A). Verify the frame size of each contactor before assembling — swapping positions will not align the mechanical linkage. No electrical connections are needed; the interlock is purely mechanical. It adds no power draw or heat to the panel. The assembly adds roughly the width of one additional contactor to the group, so account for that in the panel layout.