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Compressor-maker develops and builds its own VSDs
Published:  15 July, 2014

The compressor manufacturer Atlas Copco has developed its first in-house-designed inverter drive, claiming that it is 70kg lighter and less than half the size of the largest comparable generic inverters.

The company has designed the Neos inverters to meet its present and future needs in terms of size, simplicity, robustness and reliability. All of its GA 37-90 VSD compressors will now come fitted with the new inverters, which will also be available as spares for retrofitting to existing GA models in the field.

According to Atlas Copco, most general-purpose, off-the-shelf VSDs are designed to cater mainly for applications such as pumps and fans, with less demanding torque requirements than those of heavy-duty compressors. It adds that compressor applications represent only about 5% of the off-the-shelf VSD market.

It has therefore designed and developed its first dedicated compressor drive, based on 20 years experience of manufacturing VSD-controlled compressors.

The new VSD follows Atlas Copco’s announcement last year that it had developed its own oil-cooled permanent magnet motors and would be manufacturing them in-house.

The new inverter has been developed, and is being manufactured, at Atlas Copco’s plant in Antwerp, Belgium.

By developing its own inverters in-house, Atlas Copco can tailor them for compressor applications

The compact design eliminates the need for a control panel. All communication is done via a CAN connection with the compressor’s Elektronikon Mk 5 controller, or via an Ethernet connection to a PC for troubleshooting. The only other I/O are a motor temperature sensor input, a relay output for the cubicle fan control, and two digital inputs for a run-enable function and service switch.

The drives are protected against dust ingress by IP5X-rated enclosures. A safe torque-off function is built in.

During the development programme, Atlas Copco conducted field-tests in a variety of hot, cold and dusty conditions, which involved running the inverters for up to 10,000 hours at maximum load. The performance of 16 drives, installed on 55, 75 and 90kW compressors, were compared in locations ranging from Finland to Bahrain. These tests proved that the Neos VSDs can operate at continuous full load in the harshest working conditions, in ambient temperatures from –20°C to +50°C.

Atlas Copco says it is backing its new inverters with a warranty that is twice as long as other proprietary drives. The VSDs are interchangeable with existing inverter brands, where retrofitting is needed. The company points out that its in-house manufacturing capabilities will give it full control over the availability of spare parts, now and in the future.