Condition monitors and fault detectors find faults in mechanical, electrical, optical or other systems before a system failure condition occurs. An example of a fault in an electrical system is an arching circuit breaker. An example of a fault in a mechanical system is a failed roller bearing. Both mechanical and electrical faults produce characteristic sounds, which can be detected using air or structure borne acoustic detection techniques.
Electrical Faults / Condition
The instrument or recorder is capable of detecting electrical faults in circuit breakers, switches, relays, transformers, motors, generators, distribution panels, switchgear, switchboards, or electrical systems or circuits for electrical power transmission or distribution. Electrical faults can include short circuits, ground faults, high impedance faults (HIF), phase faults, asymmetric faults, overload conditions, power deficits and power excesses. Arcs, discharges or other electrical faults that can produce an audible or ultrasonic noise (hum or buzz), as well as visible or UV light emission, can be detected by sound microphones, ultrasonic transducers, acoustic emission sensors, or UV sensors. Electrical faults at lower amperage can produce thermal emissions, which can be detected with optical infrared sensors. Many electrical faults can be detected by monitoring circuits for changes in phase current, phase voltage, power direction, current zero sequence, frequency changes, and temperature.
Mechanical Faults / Machine Condition
Instrument or recorder is capable of detecting mechanical faults or monitoring the machine condition of rotating mechanical systems or system critical components such as bearings, couplings, shafts, gears, transmission, belts, pulleys, slides, guides, motors, actuators, or other mechanical parts or mechanisms. Acoustic emission instruments can to monitor conditions and detect changes in mechanical systems. Mechanical components and fault produce specific acoustic or vibrational responses. Changes in the acoustic emission or spectrum can indicate a fault or deteriorating condition. For example, if a break, deformation or other failure occurs, acoustic emission (AE) sensors can detect the burst of high frequency caused by the event.
Process Faults / Condition
The instrument or recorder is capable of detecting process faults or monitoring the condition of process systems or critical system components such as valves, pumps, pressure vessels, piping, pipe fittings, tanks, mixers, or other process parts or equipment. Acoustic emission instruments can monitor conditions and detect changes in process systems. For example if a break, leak, blockage, deformation, or other failure occurs, acoustic emission (AE) sensors can detect the burst of high frequency caused by the event. Monitoring acoustic emissions can also access the location and severity. This NDT technique is particularly useful in determining the structural adequacy of tanks and pressure vessels. AE is also used for the detection of faults or leakage in pressure vessels, tanks, and piping systems. Welds and stress corrosion cracking can be monitored on-line with AE techniques.