Nova Chemicals needed a permanent system for replacing any one of 37 electric motors used for generating hydraulic power. ‘From condition monitoring results the motors need to be replaced routinely and it is crucial that this happens as quickly as possible so as not to interfere with production,’ said Nova Chemicals engineer Steve Birch.
The company previously used a forklift truck with chain blocks, but this was proving to be too time consuming.
Access above the 400kg (880 lb) motors is tricky. The motors are housed in hydraulic units in two banks that run parallel to one another. The runway beams that were installed above each bank had not been erected down the centre line. Furthermore, the beam on the left hand side was also surrounded by pipe work and cable trays that prevented anything from travelling along it.
Lifting Gear Hire and Lifting Gear Engineering designed, built and installed a manual rolling bridge crane, 3m wide, that attached to the two existing runway beams. It has a 3m span and 1m cantilever. LGH suspended a new 25m runway beneath the existing left beam so as to provide a mounting platform beneath the pipe work and cable trays surrounding the girder above it. The other beam could be used in its existing state. Maximum lifting height is 6m.
With this design the motors could be lifted from either bank and placed on a pallet in the passageway ready to be taken away for repair.
