Pneumatic tools like impact wrenches and air ratchets require a steady supply of high-pressure air to operate. An air compressor uses an electric motor or gas engine to drive a piston pump, drawing in air and squeezing it into a steel storage tank. The compressor automatically shuts off once the tank reaches a preset pressure limit (typically 125 to 175 PSI) and kicks back on when the pressure drops.
Compressing air generates significant heat, which condenses into water inside the steel tank. You must open the drain valve at the bottom of the tank daily to drain this water. If left inside, the water will rust the tank from the inside out, leading to catastrophic failure, and will travel through the hoses to rust your air tools. Use an inline water filter and oil lubricator to protect your equipment.