What Is a Dual-Speed Compressor?

As an industrial or manufacturing business in the UK, you might be wondering how you can improve the performance and energy efficiency of your equipment to reduce your running costs and electricity bills. One simple way to achieve this is to use a dual-speed air compressor to reduce the off-load energy consumed, once the upper pressure set point has been reached.  However, before deciding whether to choose a dual-speed compressor as opposed to a single-speed or variable-speed alternative, you need to know how each compressor works, their pros and cons, and how they can impact your critical business processes.

Anglian Compressors has been one of the UK’s leading compressed air specialists for almost five decades so you can trust us for honest, reliable, and can offer up-to-date advice based on the latest technologies. Give us a call to learn more about the benefits of dual-speed compressors. Keep reading to find out how dual-speed solutions stack up against the alternatives.

Understanding Commercial Air Compressor Types

Here is a quick overview of the different types of compressors used in industries such as pharmaceutical, industrial, engineering, food and drinks, and many more. 

Fixed-Speed Compressors (Single-Speed)

A standard fixed-speed air compressor is either loaded (making air), off-load (running, but producing no air) or off. This means that rather than having multiple speeds, a fixed-speed compressor can only run at 100% capacity when in use. If you don’t need all of this air, the pressure in the system increases.  When the upper-pressure set point has been reached, the compressor goes ‘off-load’.  As a result, a fixed-speed compressor will have to run ‘on-load’ and ‘off-load’ in continuous cycles to maintain a specific air pressure.  Off-load is where it consumes approximately 35% of the full load current, but produces no air, therefore at this time, it is very inefficient.  

Benefits and drawbacks of single-speed compressors

While not the most energy-efficient compressors on the market, fixed-speed compressors are usually the most affordable type of compressor when it comes to initial purchase cost. However, because they run off-load at times, which is a waste of energy, the operating costs are much higher.

Dual-Speed Compressors

Unlike fixed-speed (single-speed) compressors that can only operate at 100% capacity (or run off-load), dual-speed compressors reduce the energy usage by reducing the energy during the off-load state.

The dual-speed compressor runs the same as a fixed-speed compressor when loaded, however, when it reaches its upper set point, it slows down to its minimum speed and then goes off-load.  As it is turning slowly, the energy to run off load compared to a fixed speed is 20% less.  When the pressure in the system falls to the lower limit, the compressor will ramp back to full speed and continue to produce air.

Pros and cons of dual-speed compressors

Dual-speed air compressors have fewer parts meaning less to go wrong.  They waste less energy and therefore save you money.  Although they cost more than a fixed-speed air compressor, this energy reduction will give you a payback in around 2 years over the fixed-speed type of air compressor.

Variable-Speed Compressors

Variable-speed compressor systems can modulate the air pressure of your compressed air systems by adjusting the speed at which your compressor’s motor operates. As the motor speed increases, so does the output of air. Generally, variable-speed compressor motors operate between 40 – 100% capacity, however, due to the superior design, the Atlas Copco VSDs range of variable speed drive air compressors can operate as low as 20% capacity.  This prevents the machines running in start-stop mode, reducing wear to the internal parts and subsequently reduces your energy costs. So, rather than a light switch that can only turn on or off, a variable-speed compressor works more like a dimmer switch.

Benefits of variable-speed compressors

Variable-speed compressors can run at various speeds to produce steady pressures that fluctuate very little, if at all. In low usage, these systems can work at speeds as low as 1000 RPM so they do not need to keep turning on and off to maintain your desired air pressure. In high usage, variable-speed compressors work at speeds as high as 6,000 RPM, allowing them to produce high pressures extremely quickly to boost your productivity.

If you are unsure of what type of compressor you need, feel free to contact us. We are always ready to offer expert advice and answer any questions you have about compressed air systems.

Dual-Speed versus Single-Speed Compressors

Dual-speed air compressor systems have many advantages compared to their single-speed counterparts. Dual-speed solutions reduce the wasted off-load energy by slowing down when off-load which can significantly lower your energy costs. 

The only drawback of dual-speed compressors compared to single-speed counterparts is the expense. Of the two options, dual-speed systems tend to be more capital expenditure, and they do not always result in noticeable savings if your air demand rarely changes, or, if you only use compressed air in short bursts.

Dual-Speed versus Variable-Speed Compressors

Because variable-speed compressors can operate at multiple speeds, which can be adjusted based on the air demand at any time, they are always more energy efficient than dual-speed compressors. They are more expensive than dual-speed compressors in terms of the initial purchase cost, however, 90% of the time the significantly lower energy usage more than pays for this.  The ROI of a Variable Speed Drive a Flex dual-speed, is less than 6 months. 

Choosing the Right Compressor for Your Needs

Here are just some of the most important factors you need to consider when deciding whether to purchase a single-speed, dual-speed or variable-speed compressor for your workplace:

Energy efficiency

Variable-speed compressors are usually the most energy-efficient solutions with dual-speed systems coming in second place. Single-speed compressors are the least energy-efficient option because they can only operate at 100% capacity: they need to run off-load at full speed, wasting energy.

Initial purchase and installation costs

Single-speed compressors are usually the most affordable option when it comes to initial purchase costs. Dual-speed compressors are generally pricier than single-speed compressors, while variable-speed compressors are the most expensive.  All of these machines cost the same to install

Air pressure control

Only the variable-speed air compressors offer precise air pressure control as both the single-speed compressors and Dual-speed compressors require upper and lower pressure set points

VSD, Dual-Speed and Fixed-Speed Air Compressor Installation and Maintenance Tips

When installing your air compressor, you should consider your space requirements. Make sure there is enough area around the compressor for ongoing maintenance and ease of operation. Depending on your environment, you might want to improve ventilation with ducts that can divert the hot air exhaust away from enclosed areas.

Like any machine, air compressors require regular maintenance to remain functional and efficient for as long as possible. Some basic maintenance tasks for air compressors include replacing air filters, checking oil levels, and cleaning external components. Additionally, it is crucial to keep the compressor clean and free of debris to prevent the unit from sustaining damage.

If you are unsure about installing and maintaining your compressor systems, it is best to entrust these tasks to trained technicians. Fortunately, if you are looking for a reliable team of experts in the UK, you do not need to search any further than Anglian Compressors. 

Do you need a new compressor to improve the performance and energy efficiency of your compressed air systems? Are you still somewhat confused over the differences between single-speed, dual-speed and variable-speed compressors? Whether you have a specific solution in mind or just need some general advice, please get in touch with our highly trained specialists.

Anglian Compressors has been at the forefront of our industry in the UK for almost 50 years and we are proud to be a premier distributor for esteemed brands that include Atlas Copco. We are based in Peterborough and operate within a 150-mile radius. So, no matter where you are located, you can count on us for all your compressed air needs. Get in touch with us today to find out how we can help you.