Winds of change: motors boost blower efficiency
21 November 2012
Atlas Copco chooses WEG's high-efficiency electric motors and variable speed drives to power its latest range of energy-efficient screw blowers. The 90, 132 and 160kW motors and drives are being used in models from Atlas Copco's ZS range of blowers, supplied for a range of demanding applications, including wastewater treatment, food and beverage manufacture and chemical processing.
Blowers produce large volumes of air at relatively low pressures – typically from 1 to 4 bar – and they are a significant consumer of energy in many industrial processes. In wastewater treatment for example, they are used to deliver air to aerobic digesters that play a central role in breaking down contaminants.
Air blowers consume up to 70 percent of the energy used by a wastewater treatment plant; indeed, this can account for around 3 percent of the total energy consumption of industrialised countries. The Atlas Copco ZS blower range can potentially transform energy efficiency in these applications, thanks to a number of improvements that succeed in reducing energy consumption by more than 30 percent compared with traditional blower designs.
Water utilities have long been seeking ways to reduce their energy consumption and, not surprisingly, a key area that the industry has focused upon has been the improvement of blower efficiency. Atlas Copco's ZS units replace the classic Roots lobe type compressor design (traditionally deployed in low-pressure air applications) with a screw compression element, which greatly increases the efficiency of the blower, and maintains these higher efficiencies across a wider range of operating speeds.
In addition to the screw compressor format, Atlas Copco made a number of other design refinements in the ZS range, including improvements to the air flow through the blower and the use of energy efficient motors and motor control.
The WEG W22 three-phase motors chosen by Atlas Copco to power its ZS blowers are among the very few motors available in their class to offer both IE2 and IE3 energy efficiency ratings. Moreover, they are designed for use in tough industrial environments, while providing an extended lifetime and lower maintenance requirements.
The frame and cooling system of the motor are optimised to deliver better airflow to its internal components, which helps to extend motor life. Special bearing seals also extend the life of the motor by protecting it against the ingress of water and dust.
These features provide motors capable of meeting not only the demanding efficiency specifications but also requirement for a component life of 40,000 hours, with re-greasing intervals of 4,000 hours. Moreover, the motors must deliver this level of reliability in operations involving 24/7 running and in hot and dusty regions where ambient temperatures can be as high as 46oC.
Standard W22 machines in efficiency classes IE2 & IE3, are available across the power range from 0.25kW to 4MW. When combined with a matched CFW11 inverter drive, even greater energy savings can be achieved with these motors.
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