Abstract
Electromagnetic tachometers (EMTs) are used with products from many different industries. Evaluation of their performance requires magnetic field analysis. We simulated the electromotive force (emf) dependence on the yoke in circular cone shape and the thickness of the cylindrical permanent magnet, using the simpler emf calculation method with the finite element method. As a result, the value of emf/ (coil turns) in this simulation was 380% of that for the current yoke shape. Next, we compared the emf of an Al-Ni-Co magnet with that of a Sm-Co magnet. For the current magnet thickness (12 mm), the emf values of the magnets were close. For smaller magnet thicknesses, (3-9 mm), however the emf of the Sm-Co magnet was higher than that of the Al-Ni-Co magnet Therefore, EMTs can be made smaller and with higher emf than current models.
