tachogeneratoren

Tachogeneratoren are electromechanical devices that convert the rotational speed of a shaft into an electrical signal, typically a voltage proportional to speed. They are used as speed sensors in feedback loops of control systems, especially in older or rugged industrial equipment, as well as in laboratory and CNC applications to monitor and regulate motor velocity.

The most common form is a DC tachogenerator, a small brush-type generator whose output voltage is proportional to shaft speed. There are also brushless and AC variants that produce a signal suitable for conversion to a DC level or for direct speed indication. In practice, the relationship between speed and output voltage is described by a speed constant, with a linear range chosen for the application.

Construction areas typically include a rotor connected to the drive shaft and a stator with windings, or in some designs a magnet assembly and windings. In brushed designs, carbon brushes collect the generated voltage. The unit is designed to provide a relatively linear response over a specified speed range, but performance can drift with temperature and aging. The electrical signal is commonly fed into a motor controller or data acquisition system as feedback for velocity control, requiring attention to load impedance and wiring losses.

Applications and considerations: tachogenerators offer a simple, robust means of measuring speed with low latency, but they incur mechanical wear and limited resolution compared with modern encoders. As technology advances, encoders and electronic tachometers increasingly supplement or replace traditional tachogenerators, though the latter remain in use in certain simple or harsh environments.