VSD air compressors have seamlessly integrated into the modern manfucturing landscape. Users value their ability to respond to demand and reduce energy costs while placing less stress on compressed air systems. They are a cost-effective and sustainable way to meet compressed air requirements.
They are, however, a relatively recent innovation in compressed air. Atlas Copco only released the world’s first commercial variable-speed-drive compressor in 1994. What led to this development of compressor technology, and why did it take so long?
A brief history of compressed air
Air compressors have been with us for a long time. The use of bellows in medieval forges is, perhaps, the precursor of compressors. Even though they were human-powered, they served a purpose that some air compressors still serve today: blowing air to help accelerate a process.
In the 18th and 19th centuries, what we would recognise as a modern air compressor was first developed. These early models were primarily used in laboratories for experiments and later evolved into steam-driven compressors, which revolutionised industrial power transmission. By the late 19th century, the modern air compressor was born. Steam-driven air compressors could transmit power over networks, helping create the Industrial Revolution.
Perfecting compressed air
The basic air compressor has been with us for more than 100 years and has remained largely unchanged – long after the technologies and practices they developed alongside had fallen into disuse. A compressor from the 1980s might be smaller, more efficient, and more powerful than one from the 1880s, but one thing remained the same: it only had two speeds, on and off.
Several factors contributed to this. One was that there was little demand for anything else. Earlier uses of compressed air often focused on powering equipment that was in use most of the time, so there was little need for variable speeds. Energy was more affordable – fossil fuels were plentiful – and concern about the environmental impact of energy use was limited.
But there was also a technological barrier. Alternating current (AC) induction motors, initially developed by Nikola Tesla, were not yet advanced enough for precise speed control. By the latter part of the 20th century, improvements in motor technology and sensors enabled the creation of VSD air compressors.
The first VSD air compressor
By the 1990s, fixed speed compressors were not meeting industrial needs. These systems operated at a single speed – on or off – wasting energy when demand varied.
Atlas Copco introduced the first commercial variable speed drive (VSD) compressor in 1994. It used an inverter with an AC motor to match output to actual demand. This cut energy use and reduced excess air discharge. Testing at several factories in Manchester and Sheffield showed energy savings of 25%.
VSD compressors offered practical advantages. They powered pneumatic tools at various speeds while maintaining air quality. This worked well in facilities where air needs changed throughout the day. The system also extended service intervals to 4,000 hours, reducing maintenance costs by £2,100 annually for a mid-sized operation.
The technology transformed compressed air systems in manufacturing. A metalworking plant in Leeds installed an early model, cutting their quarterly energy bill by a quarter. The workshop manager noted that the compressor’s quieter operation was an unexpected benefit for workers on the factory floor.
More innovation
Naturally, the development of VSD air compressors has continued. Further research has increased their efficiency. Modern VSD compressors incorporate advanced sensors and control systems, allowing for precise adjustments and remote monitoring through IoT platforms such as SMARTLINK.
VSD compressors have also taken advantage of advances in technology elsewhere. The internet was just starting to enter the mainstream when the first VSD air compressor was introduced. Now, it is integrated with compressors that can offer real-time, remote monitoring.
Atlas Copco’s VSD+ range exemplifies this progress. These compressors feature simplified internal mechanisms with fewer parts, increasing reliability and efficiency. They eliminate the need for blow-off pressure and offer up to 50% energy savings. They never run in an unloaded condition and, because of the motor’s high torque, can start under pressure, eliminating the need to blow off the pressure. Combined with Atlas Copco’s Airlogic2T controllers and SMARTLINK, they can be monitored and optimised anywhere in the world.
Having introduced savings of around 30% with their first VSD air compressor, their new VSD+ range offers users an average of 50% in energy savings.
The future of VSD air compressors
VSD compressors have been widely adopted for decades. Industries such as food and beverage and pharmaceuticals rely heavily on VSD compressors for their ability to provide clean, controllable compressed air. Any use that needs a variable supply of compressed air can benefit from a VSD compressor, therefore, manufacturers continue to develop and improve their range.
Further integration with IoT is inevitable. *As sensor costs decrease and AI technologies mature, new VSD models will offer predictive maintenance and further energy optimisation. As components come down in price, size, and accuracy, their ability to monitor systems and offer early problem detection means that new ranges will likely offer more significant savings by enabling rapid preventative maintenance.
Artificial Intelligence (AI) and machine learning are also likely to play a bigger role in compressed air. With many businesses already seeing the benefits of data collection from audits and their monitoring systems, AI is an obvious next step – allowing levels of analysis of compressed air use and changes that simply are not possible otherwise. It might mean that air compressors will appear to have a sixth sense in a few years, getting themselves ready for air demand before the users themselves know they need it!
Choosing the right VSD air compressor
Selecting a suitable variable speed drive (VSD) air compressor requires matching the system to your air demand pattern. For fluctuating usage, common in most workshops, a fixed speed compressor often uses more power than necessary.
Begin with an air audit. Measuring your compressed air needs in litres per second helps determine the appropriate VSD model – whether screw compressor, oil-free unit or air-cooled design. VSD compressors adjust motor speed based on demand, reducing electricity consumption and wear on components. A typical 75 kW unit operating at partial load can save up to £7,500 annually on energy costs compared to conventional models.
VSD compressors use an inverter with an AC motor that runs at different speeds as required. This reduces energy use compared to fixed speed systems that run continuously regardless of demand. The monitoring systems on newer models record performance data and alert staff when filters need changing, typically after 2,000 hours of operation.
Consider your workshop conditions when choosing. Units installed in the West Midlands metal fabrication sector often need additional filtration due to airborne particulates. Most models come with three-phase power options and connect to existing pipe networks with standard BSP fittings. For expanding businesses, selecting a unit with 15–20% additional capacity prevents the need for replacement during periods of growth.
J Ll Leach technicians conduct site surveys and air audits. We help customers select equipment based on measured requirements rather than manufacturer specifications. Many of our Staffordshire clients have found that upgrading from fixed speed models reduced their quarterly electricity usage by 22%.
If you need assistance with your compressed air systems, reach out to experts at J LL Leach for tailored solutions and system design. With decades of experience, we can provide you with various services, such as a quick chat to discuss your needs, an audit to help you make informed decisions, or even design a complete system to ensure you are getting the most out of your compressed air systems. Just get in touch.
FAQ
What are the main advantages of a variable speed drive air compressor over a fixed speed compressor?
A variable speed drive (VSD) air compressor adjusts motor speed to match air demand. This saves energy and reduces wear on components. Fixed speed compressors run at full power, regardless of need, and use more electricity.
At a Birmingham manufacturing plant, replacing a 45 kW fixed speed unit with a VSD model cut energy usage by 27% over six months. VSD compressors work well in factories where air requirements change throughout the day.
Can a VSD compressor be used with existing pneumatic tools and automation systems?
Yes. VSD compressors work with standard pneumatic tools and existing systems. They connect to normal air lines using BSP fittings and deliver consistent pressure despite varying motor speeds.
A Coventry automotive parts supplier uses VSD compressors with their robotic assembly line without modification to the air distribution network. The units record operating data, showing when filters need replacing (typically every 2,000 hours) and logging power consumption.
How do I choose the right VSD compressor for my needs?
Start with an air audit to measure actual usage. Consider your workshop’s air quality requirements and whether you need oil-free operation. Calculate your air consumption in litres per second, including a 15% margin for future needs.
Check the installation space – most units need 600 mm clearance for ventilation and service access. Look at noise levels too – VSD models operate at around 67–72 dB, which is important if the compressor sits near work areas. Atlas Copco and other manufacturers supply units from 7.5 to 250 kW with standard 415 V three-phase power connections.
