Air-start system

An air-start system is a power source used to provide the initial rotation to start large diesel engines and gas turbines.

When starting the engine, compressed air is admitted to whichever cylinder has a piston just over top dead center, forcing it downward.

[2] As the engine starts to turn, the air-start valve on the next cylinder in line opens to continue the rotation.

All vane type air starters should have a lubricator installed to insure long-life and maximum performance.

[4] Lubricators give the moving parts a needed friction barrier, reduce metal corrosion and keep vanes sealed properly against the cylinder walls.

Even the so-called lube-free air starters require lubrication to prolong trouble free life.

One is an in-line or reservoir type that typically stores up to 2 quarts of lubricant, and is installed along the air supply line.

It has a dual function as a generator (is known as a starter/generator) at speeds above which the engine no longer requires starter assistance.

Air starter on Caterpillar Diesel Engine
Air-starter high pressure on a Cummins Engine. It is mounted at the flywheel housing in the engine. The starter when receive air or gas start to engage the pinion in the ring-gear. After engine gets the firing speed pinon disengage.