[Application Note 40518] Piezoelectric transducers produce small electrical charges in response to pressure. Their sensitivity, ruggedness, and stability at high temperatures make them an essential building block of many accelerometers and pressure sensors. Applications include turbine vibration measurement (accelerometers) and combustion dynamics monitoring (pressure sensors). Typically, the high-impedance charge output produced by a piezoelectric transducer must be conditioned and amplified before transmission across system cabling to the data acquisition and measurement instrumentation. This conversion is accomplished with a device called a charge amplifier. Problem Over time, a charge amplifier’s signal response can drift. Damage to the charge amplifier or associated [...]

Tire manufacturers wants to satisfy their customers, and protect themselves from liabilities, manufacturers are moving to 100% tire inspection for defects and abnormalities. Defects not only cause potential safety issues but they can also introduce unwanted vibration into the vehicle suspension system. Belts can be overlapped, or not cover the complete tire surface, causing weak or bubbled areas and imbalances. The tread depth can be too shallow, leading to decreased service life. An uneven tire can cause excessive runout and vibration. MTI was approached by a major manufacturer requesting a solution to measure tread depth, runout and blistering. They [...]

[Application Note 11718] One of the primary concerns in large generator design is vibration. Excessive vibration can lead to premature breakdown of insulation and other materials, ultimately resulting in early failure of the generator itself. The Problem A leading manufacturer of power generating equipment required a sensing system able to measure stator bar vibration in a partial generator mockup. Specifically, the company’s multi-day testing program demanded a sensing system that was immune to the large magnetic field generated by live stator bars capable of withstanding high heat built up from prolonged testing, and compatible with a proprietary stator bar [...]