High Efficiency Motors Are Big Cost Savers

29 June

As Africa’s mines work to hold down costs and extract more value from their assets, modern high efficiency motors from Zest WEG Group are helping to cut energy bills and maintenance.

Almost two-thirds of the power consumed by the mining sector is associated with electric motors, so these items of equipment are important for mines to look at when demanding savings, according to Zest WEG’s Group African business development executive, Edson Cristofolini.

A typical mining site highlighting a number of electric motor applications.
“Where an old 55 kW motor is operating 24 hours a day and seven days a week, we estimate that a mine can save over to 20 MW a year by replacing it with a new WEG Top Premium Efficiency IE3 motor,” says Cristofolini.

These savings add up when considering how many motors are operational on a large mine, he says. Apart from reducing energy consumption, the WEG IE3 motors also contribute to mine profitability through their long life, low maintenance and reliability.

“Repairs and replacements are especially costly and time consuming for mines in remote locations, so these motors are designed to operate reliably under harsh operating conditions,” he says. “An important aspect of the design in the WEG Top Premium Efficiency IE3 range, for instance, is the Class H Insulation with class B temperature rise.”

This provides a buffer of 60°C between the motor windings average operating temperature and the actual motor insulation capability, protecting the motor where quality of power varies or where ambient temperatures are very high.

This robust design also provides a service factor of 1.15, allowing a motor to be overloaded by up to 15% continuously without compromising reliability. With the lower losses and the reduced operating temperature of these high efficiency motors, bearing temperatures are also lower

“Lower bearing temperature means that less grease is used, and the intervals between the re-greasing of bearings are longer,” says Cristofolini.

Dust and water ingress is prevented by the unique WEG W3 Seal arrangement, which comes with an IP66 rating; this is the highest level of protection before entering the category of submersible motors.

“Taking into account that many mine sites often do not have extensive workshop facilities, the motors are designed for easy installation and maintenance, with solid feet and increased terminal box sizes that allow easy connections,” he says.

He emphasises that it is worthwhile for mines to prioritise the total cost of ownership with high quality design and efficient performance in their choice of motors, with reduced maintenance and operational costs, as the capital cost makes up only about 2% of the motor’s cost of operation over a 10 year life. According to Edson, the WEG Top Premium Efficiency IE3 motor range offers the lowest Total Cost of Ownership for the mining sector in Africa.

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