High-efficiency motors are cost savers

Electrical Power & Protection

August 2017 Electrical Power & Protection

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 they are important for mines to look at when demanding savings,” says Zest WEG’s Group African business development executive, Edson Cristofolini.

“Where an old 55 kW motor is operating 24 hours a day and seven days a week, we estimate that a mine can save up to 20 MW per year by replacing it with a new WEG Top Premium Efficiency IE3 motor,” he adds.

These savings add up when considering how many motors are operational on a large mine. 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,” explains Cristofolini. “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 to allow easy connection,” adds Cristofolini.

He emphasises that it is worthwhile for mines to prioritise the total cost of ownership through quality design and efficient perform-ance 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 Cristofolini, the WEG Top Premium Efficiency IE3 motor range offers low total cost of ownership to the mining sector in Africa.

For more information contact Kirsten Larkan, Zest WEG Group Africa, +27 (0)11 723 6000, [email protected], www.zestweg.com

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Electrical Power & Protection

High-efficiency motors are cost savers

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