Understanding Air Compressor Specifications
It’s easy to get overwhelmed when shopping for an air compressor and reviewing the various specifications and other data. Here’s a brief rundown of what some of the most commonly cited facts, figures and configurations mean:
- Pressure: An air compressor’s primary goal is to pressurize air. We measure its ability to do this in pounds per square inch gage, or PSIG. Most pneumatic tools require 90 PSIG to operate. Heavy-duty applications may require more.
- Capacity: The capacity of an air compressor is the amount of air it can produce at a specific PSIG. Capacity is measured in cubic feet/minute, or CFM. Capacity is an important factor in air compressor selection if you intend to run multiple tools at once.
- Horsepower: All compressors have an engine. As with automotive engines, we measure the amount of work it can perform in horsepower. One important thing to remember is while a minimum amount of air compressor horsepower is required to deliver certain levels of pressure or capacity, many compressors are overpowered and inefficient. A well-designed compressor should be able to produce 4 CFM at 100 PSIG for every unit of power.
- Tank size: Most compressors have a tank to store pressurized air. A larger tank means you can go longer without running the compressor motor while still having enough air on hand to power your tools. However, some larger tanks are often more expensive and can take up more space in your work area.
- Duty cycle: An air compressor’s duty cycle is a measure of the amount of time it can run before needing to be shut down. We express duty cycle as a percentage. For example, a compressor with 15% duty cycle would need 8.5 minutes of downtime for every 1.5 minutes of run time. Heavy-duty compressors typically have a duty cycle of 35% or higher. Compressors with a 100% duty cycle are considered “ultimate duty.”
- Motor type: Air compressor motors are typically either electric or gas powered, though alternative fuel machines are slowly becoming available. Most electric motors are suitable for standard duty or home use only. Gas-powered air compressors tend to be more powerful and offer portability.
- Lubrication: Most air compressors have movable parts that are lubricated to reduce wear. Alternately, oil-free compressors are available and often used in clean environments where there can’t be any contamination.
- Regulation: Pressure regulation is essential for larger HP units that don’t need to be running at full capacity all the time. An air compressor pressure regulator avoids having to continually start and stop the motor. The two main types are load/no load control — which vents the unit when a given pressure is reached — and modulation control — which throttles the inlet plate, causing the unit to draw in less air.
- Cooling features: Cooling an air compressor is essential to preventing failure during continuous use. Several different technologies achieve this, including heat exchangers, intercooling, diaphragm cooling and more.
- Mounting options: Compressors come in all shapes and sizes, including portable, stationary and trailer-mounted units. Choose the configuration that gives you the most flexibility but beware of the additional footprint a larger model will have and always check that your power supply is adequate.
Need more information or want to learn about the various additional options available on our products? Contact a Quincy Compressor representative for assistance or use our sales and service locator to find a dealer near you!