gears Archives - International Mining

Bauer Geared Motors, a business division of Hudaco Trading Ltd, has been awarded a contract to deliver a total drive solution that includes five large sized 750 kW industrial gearboxes and two 185 kW units for the Tippler upgrade project at the Saldanha Iron Ore export terminal in South Africa.

Weighing up to 15 t each, the 750 kW gearboxes are the largest machines ever supplied by Bauer.

Bauer says it has been a market leader in electric drives since 1984, initially specialising in geared motors. The Hudaco power transmission division later diversified, expanding its portfolio to include industrial gearboxes and transmission solutions.

It joined the Hudaco group in 2002 and, in the same year, became a supplier to Saldanha providing slew and bucketwheel drives. Bauer upgraded these drives after 10 years of operation and, in 2020, supplied a third slew drive with planetary gearboxes, and an overland conveyor.

When Derek Gilmore joined Bauer as Managing Director – Drives and Motors, in June 2019, the Tippler upgrade project for Saldanha Iron Ore port fell under his auspices. He explained that the company responsible for overseeing the project favoured a total solutions supply chain through a single sourced provider.

“The fact that Hudaco is a listed supplier to the Saldanha Port operation paved the way for Bauer, as part of the Hudaco group, to put in a bid on the drive requirements for this project,” he said.

Bauer proved compliance on design and all critical criteria as specified by the main consulting house.

The full scope of supply from Bauer includes industrial gearboxes, medium-voltage electric motors, drive base plates, high- and low-speed couplings, brakes, actuators, parts and spares as well as condition monitoring.

“We will also be responsible for torque arm and complete drive assembly,” Gilmore added.

“Our industrial gearboxes are manufactured by India-based OEM, Elecon Engineering Company Ltd, one of the largest manufacturers of industrial gear units in Asia,” he said. These gearboxes boast a service factor of more than two and 100,000 hours design life, according to the company.

The 750 kW gearboxes, two parallel drive systems and three parallel and tandem drives, will be installed on a sacrificial conveyor and a 283 m long overland conveyor, respectively. The 185 kW units will drive an adjustable shuttle conveyor.

Compliant with necessary and important thermal criteria, the 750 kW gearboxes are equipped with a cooling and forced lubrication system with dual oil pumps, one serving as a backup unit. Gilmore explains that, in addition to machine longevity, this system is also a safety feature, keeping the drive temperature to below a safe-touch of 70°C.

Bauer will also be responsible for providing the condition monitoring sensors to facilitate remote monitoring of the gearboxes, including motor speed and motor windings temperatures, brake wear and temperatures, oil levels and flow pressures, as well as bearing wear and vibrations.

“Early detection allows for a planned shutdown to do the necessary maintenance, thereby avoiding critical failure and costly downtime,” Gilmore noted.

He said Bauer is also supplying large 710 mm diameter hydraulic disk brakes for the sacrificial and shuttle conveyors in collaboration with supply partner, Magnet Service Binder.

Vibrating screen and feeder original equipment manufacturer (OEM), Kwatani, is promoting the need for high-quality engineering and the strictest tolerances for unbalanced motors and gearboxes to ensure components can run over the long term.

The harsh operating conditions that screens face in mining operations makes having these safeguards in place all the more important, it says.

According to Kenny Mayhew-Ridgers, Chief Operating Officer at Kwatani, local design and manufacture to the highest standard is a “non-negotiable”, with the OEM designing its own range of motors, as well as locally manufacturing the gearboxes for its vibrating screens.

“We design our own motors with local conditions in mind, giving the customer a high performance and long lasting product,” Mayhew-Ridgers says.

This includes optimal sealing arrangements for keeping electrical components dry and clean, Kwatani says. Power cables, for instance, must always enter from the underside to prevent water ingress, while the design must consider various orientations of the motor, depending on the angle of installation. Dusty conditions on mines also present a challenge that need to be addressed.

“Dust ingress can compromise the sealing configuration of the lid,” he says. “Our design is therefore like a top-hat, so the O-ring is not on a flat surface but rather on a cylindrical, vertical surface. There is even a double-sealing arrangement for the lid, which includes a gasket.”

Kwatani’s gearboxes are locally manufactured, with only the high quality bearings imported direct from leading global producers, it says. Gearboxes comprise two shafts, each with its own set of unbalanced weights linked to each other by a gear to achieve synchronised motion. Gears and shafts, meanwhile, are locally fabricated by selected suppliers, while the housing is cast by a local foundry and machined to exacting specifications.

“We have spent a great deal of effort on the sealing configuration, to ensure no oil leaks,” he says.

Mayhew-Ridgers says Kwatani is probably the only OEM that services its own gearboxes. This, he says, ensures adherence to strict tolerances, so that units have sustained performance and longevity.

He also highlights the massive centripetal forces exerted on the screening machine by the unbalanced motor and gearbox, which makes it vital to secure them well to the screen.

“To achieve this, we specify our own fabricated bolts, nuts and washers,” he says. “If sub-standard fasteners are used, components can come loose and cause extensive damage.”

Unbalanced motors usually have to be installed at an angle. Taking account of the weight of these components, there are rigging points all around the housing to manipulate the angle of installation. The feet of are normally larger in Kwatani installations than those of competitors, for a better contact surface, the company says.

“If there is the slightest imperfection in the flat surface of the join, this can cause costly damage to the drive and the screen,” Mayhew-Ridgers says. “This is why OEMs like Kwatani have such detailed installation procedures on issues like torqueing of bolts. Installers and maintenance teams need to stick closely to these specifications.”

Bauer drives Tippler upgrade project at Saldanha iron ore terminal

Kwatani makes manufacturing commitment on comminution equipment