TT-949: Battery Extractor Magnet Shaft Tensioners

Tech Tip-949 Models Affected: Operator Aboard Battery Extractors with Shaft Mounted Magnets

The shaft tensioning screws on the Battery Extractor (BE) magnet shaft assembly are important and should be regularly monitored for proper adjustment. Failure to inspect and maintain this hardware could result in damage to the magnet mounting plates, magnet mounting hardware or the magnet assemblies.


BE units built prior to 2012 utilized a swivel head type set screw and locking nut as the shaft tensioning screws. Since 2012, standard 3/8” x 2” set screws with locking nuts have been used instead. Regardless of the hardware used, the shaft tensioning screws must be kept tight to avoid damage to the magnet mount and components. If the shaft tensioning screws become loose, the magnet assemblies will lean forward. With the magnet assemblies not contacting the batteries squarely, the mounting hardware can be damaged or the mounting bolts can grind against the mounting holes causing deformation / elongation. Damage such as broken proximity switch covers could also occur to the magnet assembly itself.


Ensuring the shaft tensioning screws are properly tightened should be part of a daily or pre shift inspection. Loose tensioners should be tightened immediately to maintain proper magnet orientation, and broken or missing tensioners should be replaced.

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