OVERHEAD CRANES
When to replace, and when to refurbish Is it better to replace or refurbish an overhead crane reaching the end of its life? At least one South African firm reckons that there are advantages to both options, and Condra, a specialist in new crane manufacture as well as crane refurbishment, believes that the choice should be very carefully considered. According to Marc Kleiner, the company’s managing director, refurbishment allows the customer to immediately realise a cost-saving over buying new and carries the additional advantage of providing an as-new machine already familiar to his operators, avoiding any need for re-training. Production can continue as before, with no change to established procedure. Buying new, on the other hand, offers the advantages of lower operating costs quickly realised, a reduction in projected overall lifetime cost, and more efficient operation as a result of newer cranes’ increased speeds, lower weights and lower electricity consumption. According to Kleiner, hoists today are as much as 50% lighter than they were 30 years ago, and the consequent reduction in crane weight also reduces the rate of wear on the overall factory structure. Signs that an overhead crane will soon need either refurbishing or replacing include brittle electrical cable loop systems, failing contactors, extreme wheel wear, structural cracks and a general increase in maintenance costs. If the customer should decide to refurbish, then the procedure generally comprises a dismantling of the crane followed by inspection 8
Lifting Africa - Mar/Apr 2020
of all brakes and mechanicals, a change of bearings, and an assessment of the overall crane structure using MPI to inspect critical sections for rust. Crane girders and crabs are also realigned, and the girders checked to ensure that they remain true. All main components are then shotblasted, reassembled and painted. Condra refurbishes not only its own cranes but also competitors’ machines. Kleiner explained that competitor crane refurbishment is becoming increasingly popular because it allows the circumvention of delays caused by long component lead times of up to 18 months. Such delays are common among European companies because they have to import their spares. As an example, Kleiner pointed to a 20-ton crane originally manufactured by a German company but soon to be refurbished at Condra’s Germiston factory, which will either reengineer or re-manufacture any parts that are either no longer available or which will take too long to import. Recent refurbishments of Condra’s own overhead cranes have included an 80-ton machine for Sishen, and two hoists and a 25-ton, 20-metrespan crane for Implats, the latter involving conversion of the existing electrical configuration from 525V to 400V. The refurbishment of Sishen’s 80 tonners was more routine, with all bearings, ropes and brake linings being replaced, and the usual checks and inspections
Refurbished 20-metre-span Condra crane for Implats
carried out before the crane was re-painted and delivered back to the mine. Besides its own machines and competitors’ cranes, Condra also refurbishes overhead machines originally supplied by companies that have recently closed. Kleiner explained that the benefit Condra gains during refurbishing, whether one of its own machines or one from a rival firm, is that its engineers can ascertain from a technical perspective precisely how the machine has been performing. “If the crane is our own, then we
