As increasingly stringent environmental legislation and regular increases in electricity tariffs continue to burden industrial operations, blower and compressor supply specialist Airgas Compressors is focusing on energy efficient motor technology to ensure measurable power savings.

According to Airgas marketing co-ordinator Andreas Stubel, the biggest cost factor of owning a compressor is its energy use. “The energy costs involved in running a standard compressor over its lifetime far outweigh the initial investment and maintenance costs. The most effective means of reducing operational costs is, therefore, through optimised energy use.”

Stubel reveals that it has been estimated that electric motors around the world consume between 30% and 40% percent of all electricity produced. “This is a major concern and in order to optimise electric motors, international regulatory organisations have introduced various standards. The most familiar is the IEC 60034-30:2008 standard set by the International Electrotechnical Commission (IEC).”

The IEC has focused on single-speed, three-phase, 50 Hz and 60 Hz AC cage induction motors in the range 0.75 kW to 375 kW, the most widely used range of motors. According to this standard, motors are produced and categorised as IE1 – standard efficiency, IE2 – high efficiency and IE3 – premium efficiency. IE4 is in development but this is still some time away.

The IE1 motor is less efficient in comparison to an IE3 motor and the core difference is in the materials used during manufacturing. The most obvious difference is the physical size of the different motors. IE3 motors are larger and heavier than IE2 or IE1.

Stubel explains that IE3 motors are so efficient thanks to a combination of various factors such as a higher mass of copper coil with thinner laminations, improved cooling fan and the use of special bearings. “Increasing the mass and cross section of copper in a coil increases the electrical energy efficiency of the motor. IE1 and IE2 motors are common in South Africa, while IE3 is seldom seen. IE3 motors will become mandatory by 2015 in countries such as Germany.”

Although IE3 motor efficiency is commonly used in the European and North American marketplace, Stubel admits that it is still in its infancy stages in South Africa. “Although the idea of energy efficiency is becoming more common in business practice, the process of implementation is a long and complex one, especially in South Africa, which has such a rich mix of industries. Mind-sets are slowly changing, and energy efficiency will become increasingly important in the near future, especially with energy costs rising at such a rapid rate.”

Stubel acknowledges that the initial purchase cost of IE3 premium efficiency motor technology is high, however, he stresses that the long-term environmental and capital savings of the new technology far outweigh the initial cost difference.  Stubel says that another approach to improve the efficiency of motor systems is through the use of variable speed drives that regulate the speed of the motor, and reduce energy usage.

What’s more, he adds that regular maintenance is another method of reducing energy consumption while increasing productivity. “Effective maintenance does not only entail individual components, but rather looking at the entire system and its performance as a whole. It is important to first establish the current condition and inefficiencies of the system by gathering operating data, before assessing the energy consumption of the system, and looking at future production needs.”

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