摘要 |
The air gap between a rotor (12) and a stator (10) in rotating electrical machinery is determined using sonar techniques. An ultrasonic signal transmitter and receiver (16) are mounted on, for example, the rotor (12) for transmitting ultrasonic signals to the stator (10) and receiving reflections therefrom. The time between signal transmission and reflected signal reception is determined by a computer (18), and the spacing of the rotor (12) and stator (10) is determined from the time, the velocity of sound, and the speed of rotation of the rotor (12). |