The convenient and non-contact mapping of operational deflection shapes is a specialty of Polytec’s Laser Scanning Vibrometers. Now even rotating objects such as fans for consumer products and vehicles, turbines or tires can be characterized under operational conditions up to 24,000 RPM.

The actual deflection shapes and resonant frequencies due to stiffening effects at high RPM  are measured and can be taken into account in the validation process of FE models. By means of the Optical Derotator order analysis and vibration measurement become feasible in a simple manner. Telemetry systems become unnecessary. Sophisticated control electronics track the motion of the rotating object, resulting in a steady position of the laser beam. The actual measurement is astonishingly simple. Due to the synchronized speed of the derotator, and the object appears to stand still.

The PSV-A-440 Optical Derotator is supplied either as an add-on for PSV-400 Scanning Vibrometers or as a complete solution comprising the rotating unit with encoder input, a control unit, an adjustable base frame for angular and height adjustment, a PSV-400 Scanning Vibrometer and a single-point reference laser. A software module installed in the Data Management System of the PSV allows easy configuration of the derotator for dynamic run–up tests and static tests.