Measurement of Turbine RPM with Hall Effect Principle

Hall effect sensory devices, invented by Edwin Hall introduced new techniques to obtain measurements wirelessly. Through the presence of a changing magnetic field, an induced current in principle gave off a corresponding voltage value. Stemming from demand for more portable and eco-friendly power generative devices, one of the current engineering solutions shifted towards bladeless turbines. The application of Hall effect sensors shown in these experiments did attempt to produce rpm measurements for bladeless turbine prototypes. With a freedom for geometric design, bladeless technologies are argued to be more cost efficient and quieter than their bladed counterpart. New challenges rose to obtain a sensor that maintained consistent data collection and robustness for both complex geometries and more importantly, environmental settings. A repurposed water flow meter (with Hall effect sensor) was connected externally to bladed and non-bladed prototypes. Under the Hall effect principle, between each revolution created voltage spikes which were analyzed through Arduino as step response signals, to continue, the rate of step impulses could then be calculated to rpm. Under various flow regions, prototypes were observed for autorotative behavior mainly in the vertical orientation. Primarily, results focused on analyzation of rate of revolutions per minute and in cases of bidirectionality and motion halt. To compare results from Hall effect experimentation, the wireless water flow meter was compared to a commercial, wired rotation sensor.