143results about How to "Accurate speed measurement" patented technology

An alternating current/direct current tachogenerator is disclosed. The tachogenerator comprises an engine base, an external flux-insulation sleeve, an external stator, permanent magnetic steels, a hollow cup-shaped rotor, an internal stator, an internal flux-insulation sleeve, hall elements, a rotating shaft, a left end cover and a bearing, and a right end cover and a bearing, wherein the external flux-insulation sleeve is fixed on the inner side of the engine base; the external stator is fixed on the inner side of the external flux-insulation sleeve; the permanent magnetic steels are embedded in clamping grooves among the parts of the external stator; the internal flux-insulation sleeve and the right end cover are fixed; the internal stator is fixed on the outer side of the internal flux-insulation sleeve; the hall elements are embedded in the clamping grooves among the parts of the internal stator; one end of the rotating shaft passes through the left end cover bearing while the other end of the rotating shaft passes through the cup bottom of the cup-shaped rotor, the central through hole of the internal flux-insulation sleeve and the right end cover bearing; and the cup wall of the cup-shaped rotor is positioned an gap between the internal stator and the external stator. The alternating current/direct current tachogenerator provided by the invention can convert the rotating speed into the corresponding alternating current or direct current electric signal to output according to needs, is free of a reversing device, a winding, a toothed slot and residual voltage, and capable of accurately measuring the rotating speed at a low speed.