Keeping things straight - laser shaft alignment

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L&S Electric's Laser Shaft Alignment

If you’ve ever spun a top, you know that a smooth rotation free of wobble results in a longer spin than a wobbly top. The same principle applies to electric motors, turbines, and all manner of rotating equipment. In any rotating system, proper balance and alignment are of the utmost importance. Error in these areas inevitably leads to mechanical stress and likely failure.

When a rotating device, like an electric motor or turbine, is coupled to a driven element like a fan blade or pulley and belt system, this alignment becomes even more important. The shafts of the rotating bodies must be aligned to within the tolerances specified by the design engineers. If not, mechanical stress caused by unwanted oscillation undoubtedly results in failure. Laser shaft alignment is the preferred method of many an engineer and technician, and for good reason.

Misalignment between a rotating driver and the element it is coupled to can be separated into one of two classes, parallel and angular. Parallel misalignment refers to a situation where the center lines of the two shafts are parallel but separate, meaning one is shifted with respect to the other in either the vertical or horizontal plane. Angular misalignment means that the center lines of the shafts are oriented at an angle to one another, whether in the horizontal or vertical plane. Either of these situations can cause mechanical failure, but both can be remedied with Laser shaft alignment.

For the same reason that lasers make excellent tools for leveling, they are perfectly suited for shaft alignment. A laser always shoots perfectly straight and can be designed to operate within the exacting tolerances necessary for precision shaft alignment. The only other method for shaft alignment commonly used today involves gyroscopes, but it is typically less precise and more cumbersome to set up and use.

Modern laser shaft alignment systems usually consist of three components. Two of the components are often identical, and are made up of an array of lasers and photo sensors. One of each of these is installed on each of the rotating components, either on the shaft itself or a flange attached to the shaft. Each laser fires into an opposing sensor. The third component is some type of electronic brain that features controls and a display that interprets the data gathered by the sensors. The system is then rotated, data are gathered, and adjustments can be made. Advanced laser shaft alignment systems can align shafts to within hundredths of a millimeter, and can even compensate for the thermal growth that occurs when components heat up during use.