Device for the contact-free measurement of the air-gap width between the rotor and stator of electrical machines

摘要

The described device determines the air-gap width by measuring the separation of light marks which a light-mark transmitter produces on the rotor surface and stator surface. The arrangement of an objective and of an optoelectronic sensor in the axial extension of the air gap to be measured is used as a distance converter. In this case, the rotor and stator light marks are imaged on the optoelectronic sensor. The latter converts the brightness distribution imaged on it into a time-dependent electrical signal which is proportional to said distribution. The evaluation of this sensor signal in an electronic circuit provides an electrical variable which is proportional to the light mark separation, and hence to the air-gap width.