PMDT Airbourne Acoustic
PD activity which is at or near the surface of an insulator will produce an ultrasonic and sometimes audible emission. Surface tracking and corona always produce airborne emissions. Other types of PD may also produce a detectable acoustic emissions. Three ultrasonic sensors are included in the kit. The range is from 20kHz to 80kHz with a center frequency of 40kHz. Surface tracking and corona are common types of PD on insulators and bushings. It can be easily detected and confirmed using the airborne ultrasonic dish.