High Temp Accelerometers ≥ +490 to +1200 °F (+254 to +649 °C)
Voltage mode (ICP type) sensors can only operate to a limited ambient temperature. The ICP sensors internal electronics is the limiting factor at high temperatures. Many test articles, such as gas turbines, steam turbines, jet engines, high power motors, exhaust systems and under the hood testing have high temperatures exceeding this types sensors temperature rating. In order to properly function at these higher temperatures a different sensor technology is needed. PCB®’s Charge Mode Output accelerometers utilize piezo-ceramic sensing elements to directly output an electrostatic charge signal that is proportional to applied acceleration. This type sensor is termed a PE style or charge mode style. These sensor can operate at extreme high temperatures.
Charge Mode Output accelerometers do not contain built-in signal conditioning electronics. As a result, external signal conditioning is required to interface their generated measurement signals to readout or recording instruments. The sensor’s charge output signals can be conditioned with either a laboratory style, adjustable charge amplifier or, for an economical approach, with an in-line, fixed charge converter. The charge amplifier converts a charge output to a low impedance voltage output. It is easier for a data system to be setup and calibrated with a simulated a voltage signal.
Since there are no electronics built into Charge Mode Output accelerometers, they can operate and survive exposure to very high temperatures (up to +1200 °F/+649 °C for some models). In addition, Charge Mode Output accelerometers are used for thermal cycling requirements or to take advantage of existing charge amplifier signal conditioning equipment.
It is important to note that measurement resolution and low-frequency response for charge mode output acceleration sensing systems are dependent upon the noise floor and discharge time constant characteristics of the signal conditioning and readout devices used.
- High Temperature Vibration Measurements
- Engine Compartment Studies
- Exhaust Component Vibration Tests
- Steam Turbine Testing
- Engine Vibration Analysis
The most popular PCB® Series 357 high temperature accelerometers specifications are highlighted below.