Replacing one of a pair of planetary gearboxes for a Mpumalanga mine recently gave SEW-EURODRIVE South Africa the opportunity to pioneer a global innovation.
An electronic solution to match the speed of an existing gearbox in a high-torque application has provided significant savings for the customer, and attracted the interest of the worldwide SEW-EURODRIVE group.
Leveraging the latest intelligent technology, the solution is a pioneering innovation providing a cost effective replacement that will ensure reliable performance.
Greg Lewis, business development Manager Projects for SEW-EURODRIVE, says the application at the mine demanded a customised and carefully considered approach.
“The application itself was in the plant where a steel-belt transfer conveyor moves extremely slowly – with the 4m diameter head pulley turning just one revolution every 25 minutes,” says Lewis.
“Two planetary gearboxes drive the pulley, with one on each side, and the mine had been facing the pending failure of one of these, which needed to be replaced.”
With the original installer of that gearbox unavailable, the mine came directly to SEW EURODRIVE, he explains. The drive specialist already has a good relationship with the mine, and has provided most of the power transmission items on the site.
“One of the key challenges was that the mine required only the one gearbox to be replaced at that stage,” Lewis says.
“It is important to understand that in this application the two gearboxes must run together, at exactly the same speed and torque. Any variation in the speeds is not an option.”
SEW-EURODRIVE was able to match one of its units very closely with the unit being replaced, but there was still a very slight difference in the ratios. This led to a 0,001 difference in the revolutions per minute.
“While this may sound insignificant, it makes a difference when the gearbox torque is a couple of hundred thousand Nm’s,” he says.
“At this high torque level, any misalignment or desynchronisation can affect the foundation and potentially cause catastrophic failure.”
With the expert input of one of SEW-EURODRIVE’s in-house mechatronics engineers, the solution uses the company’s MOVI-C technology in a way that has never been done before.
The new planetary gearbox supplied by the company will match the torque of the original gearbox – ensuring that they turn at precisely the same speed.
The solution involves removing the existing base plate and providing a new, drop-in solution with an SEW-EURODRIVE planetary gearbox – designed to match the current infrastructure in the plant.
“The technology on our planetary gearbox constantly changes the torque to match the existing equipment,” he said. To prove this intelligent design, SEW-EURODRIVE built a small-scale working mock-up for the customer to witness. Together with its own customised base-plate, the ‘model’ arrangement was taken to site and demonstrated to the customer’s satisfaction.
The mock-up was so successful that SEW-EURODRIVE colleagues around the world asked to see it, so that they could learn from the achievement. It was also a showpiece at the company’s exhibition stand at the2022 Electra Mining Africa event near Johannesburg.