Machine Design

Energy-efficient bearings cut power costs


Manufacturers worldwide face a constant battle with rising energy costs. For PT. Leuwijaya Utama Textile Co. (Leuwitex), based in Bandung, Indonesia, a recent salvo was a government-mandated 18% increase in electricity costs in July 2010. The plant produces almost 2 tons of high-end and custom-made fabric every day, running hundreds of textile weaving, spinning, and twisting machines consuming 2,120 MW-hr per month.

Twisting machines — equipment critical to fabric quality — accounted for 30% of the factory’s energy consumption. Mechanically, the machines are fairly straightforward, consisting of lines of motor-driven spindles. Frictional losses are primarily tied to the quality of the bearings fitted at each end of every spindle. With 176 twisting machines operating 24 hr/day, and each having 256 spindles, this was clearly an opportunity for saving energy.

Plant engineers initially tested three options to lower the bearings’ frictional losses at the best overall cost. These included new bearings from the spindle supplier; low-cost Chinese bearings; and Energy Efficient (E2) bearings made by SKF, headquartered in Göteborg, Sweden. Technicians installed the various bearings in three separate spindle lines and monitored energy consumption for three months. Results showed the E2 cut energy use by around 10%, and would deliver the most energy and cost savings, according to Leuwitex officials.

The SKF bearings also did not affect textile production. “Product quality was exactly the same as before with constant, uniform delivery of the various designs, material thickness, and feel,” says Leuwitex Plant Manager Mr. Zenzen.

The Leuwitex factory now has 25,600 SKF E2 bearings running on its machinery, and the company is indeed seeing the projected energy and financial savings, says Zenzen.

E2 deep-groove ball bearings are part of SKF’s performance-class of energy-efficient bearings. According to SKF officials, E2 deep-groove ball bearings reduce frictional losses by 30% or more compared to comparably sized standard SKF bearings. The performance increase comes from an engineered internal geometry, low-friction grease, and a low-friction polyamide cage.

Designed for grease-lubricated, light-to-normalload applications, SKF E2 bearings also consume less lubricant than comparable SKF Explorer bearings and have longer expected lives. Shielded SKF E2 bearings can last twice as long as comparably sized shielded standard SKF bearings, say company officials. This means that the number of bearings needed to run an application over its lifetime can be halved. In addition to textile spindles, SKF E2 ball bearings are typically used in electric motors, pumps, conveyors, and fans.

© 2013 Penton Media, Inc

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