You’ve found the right compressor for your downstream air tools in terms of pressure and air flow, but you keep stumbling across of the term compressor duty cycle. What is duty cycle and is it important?
The simple answer is yes, very.
What is a compressor’s ‘duty cycle’?
The run time of a compressor is the amount of time it can be run on full load before it needs a period of rest to cool down. The amount of run time versus the down time required is known as the ‘duty cycle’ which is usually expressed as a percentage. Simply put, the duty cycle is the percentage of time that a compressor can run versus how long it needs to rest before it can start compressing air again.
How duty cycle works
For example, during an hour of operation under standard conditions, a compressor which has a duty cycle of 25% would be able to run for 5 minutes on full load before needing 15 minutes off.
A 50% duty cycle compressor with a maximum runtime of 5 minutes would be 5 mins on, 5 mins off repeated 6 times to make up the hour. Not, as it may be assumed, running for 30 minutes with 30 minutes off every hour.
This can have quite a significant impact on how a compressor can be used, and can significantly affect the life expectancy of a compressor if the compressor is not used properly. Only a compressor designed to run with a 100% duty cycle can be run continuously with no adverse effects on performance or lifetime of the machine or air tools.
Why duty cycle is important
Compressed air is vital to many businesses, and is used to power various pieces of equipment, from pneumatics on manufacturing lines, to hand held tools and even fibre optic cable installation equipment. The length of time that each of these applications requires compressed air to complete the job varies from intermittently to continuous. This is where the duty cycle comes in. If a compressor with a 25% duty cycle is used to power a requirement for continuous air then it won’t be long before problems arise.
What happens if the compressor duty cycle is ignored?
When the cooling off time required for a 25% or 50% duty cycle compressor is interfering with day-to-day business operations then the natural temptation is to keep the compressor running, pushing it to its limit. However, running an air compressor beyond its duty cycle limit leads to over-heating, premature wear and tear on the motor, higher maintenance costs and, at its most extreme, breakdowns which can seriously affect business productivity.
So, what can seem like a good deal on the price of your compressor can actually become an expensive mistake, not to mention a lot of additional hassle if the compressor can’t keep providing air for as long as you need it. Understanding the terminology of compressors alongside just pressure and flow is key to keeping you and your business up and running.