Gearbox Refurbishment at Big Pit National Coal Museum

Tender description

Refurbishment of existing gearbox Gearbox specification: David Brown H3-500 Foot mounted gearbox. Gear Ratio: 57.7:1 Serial Number: G240006 Summary of gearbox fault: The gear wheel on the third motion shaft is moving on the shaft approx. 0.053” when the gearbox is subjected to 100 amps static load. The bearings on the third and final motion shafts have at some point been rotating in their housings causing a small amount of wear. This has now been prevented by use of bearing retainer. Suggested works to repair gearbox: • Pick gearbox up from ourselves at Big Pit. • Strip gear unit. • Clean components. • Metal particle inspection of gear teeth (NDT). • Manufacture new special third motion pinion shaft. • Remove gear wheel from pinion shaft. • Manufacture new key. • Clean up bore on gear wheel. • Assemble gear wheel and new third motion pinion shaft including new distance piece if required. • Replace bearings. • Skim & bore gear case. • Rebuild gear unit. • No load spin test. • Supply and fit David Brown heavy duty cone ring Flexible type 18 half coupling. (small hole half) • Supply new set of pins and cones. • Deliver gear unit back to ourselves at Big Pit by the 15th March 2021.