guide to air compressor duty cycles
- Mar 28, 2023
The duty cycle of an air compressor is a measurement of the difference between its operating time and resting time. Choosing the right air compressor can be a little difficult if you don’t understand how the duty cycle works. That’s why we created this article – explaining this special feature and its importance to your purchasing decision.
How to calculate duty cycle?
An air compressor’s duty cycle, often known as run time against rest time, is determined using the total compressor cycle time—from when the compressor runs, stops, and runs again. Typically, the duty cycle is used to help define the amount of time the compressor will cycle on and off while operating at a consistent pressure (PSI) and flow (CFM).
A complete cycle is considered the time it takes to use and fill the air compressor tank. That’s why the air compressor run time calculation must also take into account compressor rest or downtime when determining the duty cycle.
The duty cycle is usually calculated by dividing the compressor run time by the overall cycle time. This formula is mostly expressed as:
compressor run time / (run time + rest time) = duty cycle percentage
Duty Cycle Percentage Comparison
BISON lists the common air compressor duty cycles on the market. With the help of examples, we will introduce the calculation methods to you again, and introduce their usage scenarios to help you understand better.
25% duty cycle
A compressor at 25% duty cycle will run for 15 minutes (one-quarter of the total cycle time) and require a 45-minute break.
The run time will be 30 seconds if your compressor has a cycle time of 120 seconds. Also, your compressor needs to rest for 90 seconds for every 30 seconds it runs.
With an air compressor with such a short run time, you can only take on small applications that require intermittent air power.
50% duty cycle
A 50% duty cycle compressor will run for 30 minutes (half the total cycle time) and require a 30-minute break.
This means that after using a tool for 60 seconds, it will need to rest for 60 seconds before absorbing air power again.
You can perform medium-scale activities that need intermittent aerodynamics with a 50% duty cycle.
If you don’t want to invest your money in a bigger compressor, then a 50% cycle compressor will be the right choice for you. You can purchase multiple smaller units at 50% capacity and run them alternately for constant airflow.
75% duty cycle
A compressor at 75% duty cycle will run for 45 minutes with a 15-minute break.
It means that if your compressor has a cycle time of 60 seconds, it will be able to pressurize the air for 45 seconds.
This applies to many applications, such as stores that use tools for a short period of time. In addition, it is sufficient to operate nail guns, air wrenches, screws, and hammers in a repair shop.
Short breaks won’t be a problem, as these tools don’t require constant air.
100% duty cycle
A 100% duty cycle compressor will run continuously for one hour and is called a constant duty cycle compressor. But 100% duty cycle rated compressor can maintain constant airflow, but only at specific PSI and CFM rates. A 100% duty cycle compressor is still prone to damage if you overwork it and use it with a tool that requires too much PSI or CFM.
These are suitable for operating tools that require uninterrupted airflow for minutes or even hours. These include pneumatic sanders and paint sprayers.
Intermittent and continuous duty cycle applications
Many people think that the closer you get to 100% duty cycle, the better. In some cases, especially in manufacturing, 0% downtime is the goal. However, for tools that do not need to run for more than a few minutes at a time, an intermittent air compressor is sufficient.
When to choose an air compressor with intermittent duty cycle
Often, intermittent duty cycles are sufficient to help you accomplish the task at hand without reducing productivity. Here are some examples:
- Filling tires or other types of inflators with air
- Powering mechanical tools, such as air wrenches and nail guns, requires only a few seconds of power every few minutes.
- Complete do-it-yourself home projects.
When to choose an air compressor with a continuous duty cycle
You may avoid downtime with continuous duty cycles by giving tools and equipment consistent power. Here are some useful applications:
- Power tools used to manufacture electronics.
- Hoisting heavy work in furniture factories and automobile factories.
- Operating conveyor systems in bottling plants.
How often should the compressor cycle?
The optimal compressor cycling frequency depends on various factors such as the size of the compressor, the type of refrigerant used, the size of the system, and the environmental conditions.
In general, the compressor should cycle on and off as little as possible to ensure efficient operation and prolong the lifespan of the system. A compressor that cycles too frequently can cause unnecessary wear and tear on the system and lead to higher energy consumption. On the other hand, a compressor that cycles too infrequently can lead to poor temperature control and reduced overall efficiency.
When an air compressor cycles quickly, it consumes more energy. Better to have longer cycle times and fewer cycles per hour to get the most out of the air compressor. Here are some ways to extend cycle time and improve air compressor efficiency:
- Use a larger tank.
- Reduce the pressure between the main storage tank and the compressor.
- Regular maintenance and inspections of the system can also help to ensure that the compressor is functioning properly and cycling at the appropriate frequency.
- Use a larger air compressor. This will allow you to run more tools simultaneously and reduce the time each instrument runs.
- Install an aftercooler on the compressor. This will cool the air before it enters the tank, which will help it last longer.
Conclusion
When it comes to air compressors, the duty cycle is important for many reasons, and hopefully, you now have a better idea of what to look for when looking at specs. Remember that the duty cycle is not a standard rating and, like decibel ratings, may or may not apply to a certain compressor. It’s a good indicator, if available, but taking this rating with a grain of salt is okay.
frequently asked questions about guide to air compressor duty cycles
What is a good duty cycle for a compressor?
A decent air compressor duty cycle typically relies on the task at hand. If you're only doing DIY work at home and using the tool every few minutes, a 50% duty cycle should suffice. If your goal is to finish painting or sanding, then you need to run the duty cycle 100% continuously, so you don't have to stop and start.
How do I know the duty cycle of my air compressor?
Checking your owner's manual is the best approach to determine the duty cycle of your compressor; it should be specified here. If not, we would recommend contacting your manufacturer directly to find out. Knowing your rating is important because you don't want to exceed it and cause premature compressor wear.
How to prevent over-cycling?
Properly sized air compressors limit the risk of over-cycling and shortening the system's life. The compressor you buy needs to operate at a duty cycle suitable for your application and meet your PSI and CFM requirements at that duty cycle.
It is important to remember that the duty cycle will also refer to PSI and CFM as a specified percentage of the total cycle time. For example, a compressor that advertises a 100% duty cycle might provide 140 PSI and 30 CFM for the entire compressor cycle time. However, the same compressor can also be advertised at 50% duty cycle, delivering higher power at 160 PSI and 15 CFM for only half of its total cycle time.
