When dealing with air tools, you will run into the phrase "duty cycle" quite often. This refers to how long the compressor motor is engaged when you are getting air supply to your air tools. There is a common 50/50 duty cycle, which means the motor runs half the time, and the other 50 percent is air supplied from the pressurized air tank. It's important to pay attention to how quickly your tools drain off the air during the "engine off" part of the cycle. If your tools drain the tank too quickly it can lead to excessive wear and premature breakdown of the compressor motor. This is true even for gasoline powered units where the engine runs constantly. Even though the engine is running, it is not always engaged and pushing air.