Hall sensors use the effect named after the American physicist Herbert Edwin Hall: When a current flows perpendicular to a magnetic field, the charge carriers are deflected to one side of the conductor by the Lorentz force, and, as a result, a voltage is produced transverse to the direction of current flow between opposing sides of the conductor. This Hall voltage is proportional to the product of magnetic field strength and current. If the current is known, Hall sensors can be used to measure the field strength and vice versa. Hall sensors are produced from thin semiconductor plates in which the charge carrier density is small and the electron speed is high. Large Hall voltages are thereby produced.
The term sensor refers to digital or analog Hall sensors which, in the FAULHABER brushless DC-motors, are usually mounted directly on the motor circuit board.
Digital Hall sensors
Digital Hall sensors are used primarily for the commutation of the brushless DC-motors and for simple speed control. In block operation, so-called digital Hall sensors only provide information about which windings are switched on or off next. The sensor signals thus have a rectangular shape.
Nearly all FAULHABER brushless DC-motors are equipped standard with three integrated digital Hall sensors and are thus ideally suited for use in combination with incremental encoders from FAULHABER.
Analog Hall sensors
Due to the higher resolution, the analog Hall sensors can also be used for exact rotational speed control or position control in addition to commutation. The option for analog Hall sensors from FAULHABER can be found directly in the data sheets of the motors under "Controller combinations." No encoder is necessary with this choice. If you opt for an analog Hall sensor, it is recommended that you use FAULHABER controllers, which are perfectly designed for the analog Hall signals.