Compressor promises significant cost and energy savings

The Interior Permanent Magnet (IPM) Motor was developed by Atlas Copco specifically for use in its new GA VSD+ compressor. This new in-house designed motor achieves an efficiency corresponding to IE 4 (Super Premium Efficiency motor class). As well as being as much as 94.5% efficient, the Atlas Copco IPM motor is also compact and specifically customised for optimised oil cooling, meaning no air flow is required to cool it. Oil cooling also has the significant benefit that it allows the motor's bearings to be constantly lubricated, giving increased levels of uptime. The lightweight and compact nature of the IPM motor has meant that Atlas Copco has been able to use it in reducing the overall footprint of the compressors themselves. This has been achieved by the use of a vertical drive train with the motor sitting on top. The motor and drive train share one drive shaft and are vertically aligned to allow a smaller footprint of 55% compared to the previous range. The whole drive train is completely closed and one oil circuit cools the motor and lubricates the element and bearings. The result is a quiet (down to 62 db(A)), reliable and compact compressor that saves space and energy while achieving higher air capacities at the same time. The IPM motor is specifically designed to power the classic Atlas screw mechanism, with the two acting as a single mechanism. There are no belts, no gears and the two elements share the same shaft and oil circuit. Of course, the use of permanent magnet motors has been reported as being under threat due to China's recent restriction on the supply of the crucial rare earth magnets needed to run them. However, according to Paul Clark business line manager of Atlas Copco's Industrial Air Division, this is not seen as a problem by the company due to new suppliers having been sourced in places such as Australia and Brazil. Oil is injected into the motor housing and runs through channels evenly around the motor, lubricating and cooling it, the bearing and the compressor element. It runs down eventually to cool the rotors. This process is repeated constantly. If the oil becomes too hot, it goes through the oil cooler first and then runs back to the drive train. Atlas Copco evaluated every part in this compressor: a more efficient fan, robust air intake system, eliminating all blow-off losses, and the best electronic components together with the new drive train add up to energy savings of 50% on average compared to a traditional idling compressor of the same type. The new GA VSD+ is another 15% more efficient than Atlas Copco's current Variable Speed Drive compressor (the GA 7-37 VSD). A full feature version with an integrated dryer is available as option. Several key components like the drive train as well as for the general design of the GA VSD+, are protected by Atlas Copco, with many patents on their way.