Motor and generator winding services suppliers specialize in producing custom motors, generators and custom windings per customer specifications, as well as companies that specialize in motor repair and refurbishing.
Optical choppers are mechanical or electronic devices that pass and then interrupt a beam of light for a known brief interval. Optical shutters are used to control the amount of time that a light sensitive material is exposed to radiation.
Tachometer generators and tachogenerators are small AC or DC generators that output a voltage in proportion to the rotational speed of a shaft. They are capable of measuring speed and direction of rotation, but not position.