Employing ‘ball-on-cylinder’ philosophy, a non-rotating steel ball is held in a vertically mounted chuck and using an applied load is forced against an axially mounted steel cylinder. The test cylinder is rotated at a fixed speed while being partially immersed in a lubricant reservoir. This maintains the cylinder in a wet condition and continuously transports a lubricating film of test fluid to the ball and cylinder interface. The diameter of the wear scar generated on the test ball is used as a measure of the fluid’s lubricating properties. The apparatus can be used, by adjusting the operating conditions, to reproduce two different wear mechanisms; mild and severe wear, the ALTE therefore has the ability to assess a lubricant’s performance in that regard.
The Aviation Lubricant Tribology Evaluator (ALTE) is a device designed to assess the relative lubricating performance of aviation turbine oils. The aim of the ALTE is to produce test conditions which allow lubricants to be evaluated on a laboratory scale, in a timely manner without deviating greatly from representative wear mechanisms.