Endevco accelerometers are used in vehicle dynamic testing of engines, exhaust systems, components and suspension systems due to their micro-miniature size, high temperature performance and rugged construction. Endevco pressure transducers are used in the automotive testing systems such as Anti-Lock Brake Systems (ABS), transmissions, fuel and oil systems due to their wide frequency response and high level of output in a miniature size, making it ideal for use in places traditionally inaccessible due to size.
|TYPICAL APPLICATIONS||REPRESENTATIVE MODELS|
|Noise, Vibration, and Harshness (NVH)||66F, 44A, 42A|
|Component qualification testing||35B, 25A|
|Road load||7290E, 7298|
|Modal/chassis design||41A, 42A, 43A, 44A, 45A, 46A|
The accelerometer should weigh significantly less than the object under test as additional weight can change the dynamic characteristics of the object resulting in erroneous data. A general rule of thumb to follow is that the accelerometer should not weigh more than 10% of the test object. Endevco’s single axis, pigtail Model 25A or 25B (side connector) and its triaxial Model 35B are the world’s smallest IEPE accelerometers weighing 0.2 and 0.55 grams respectively. For those applications where a slight amount of additional weight (0.5 grams) is acceptable there is a triaxial mounting block available (2950M16) for the 25A and 25B. These products will handle many of the component qualification requirements. Where even more lightweight accelerometers are needed, test professionals may want to consider piezoelectric Model 22 (0.114 grams).
Noise, Vibration and Harshness (NVH)
As excessive vibration plays a major role in vehicle safety, passenger discomfort and high repair costs, manufacturers continually test those areas where vibration problems are most liable to occur. These typically are the braking system, engine, motors, radiator fan, seat, steering, suspension, transmission and wheel. IEPE technology is most commonly employed with both single axis ( 42A) and triaxial (44A) modes in a networking TEDS configuration. The 42A is available in five sensitivities and the customer may select the mounting stud size that is included standard with the unit. There are special instances, such as the study of motion sickness, where a low range DC accelerometer is required. Here the single axis 7290D (TEDS) or the triaxial 7298 might be appropriate.
Transmission and other pressure tests
The 8530B piezoresistive pressure transducer is used in for transmission test applications and is compatible with such Endevco electronics as the 126 and 136 general purpose three channel conditioners, or the 4990A-X (Oasis) multi-channel rack. As media in measurand port is exposed to CRES, Parylene C, epoxy and the Viton O-ring, care must be taken to ensure this sensor is not used with high pH or low pH liquids. The lower pressure 8510 C is often used for monitoring vehicle cabin pressures during door slamming or air bag tests. For higher temperature applications (1000 ͦF) such as combustion testing, the more appropriate choice would be the piezoelectric 522M17 pressure sensor. Featuring Inconel construction, this all-welded sensor includes an integral hardline cable. Electronic accessories include the 2771C in-line charge converter for use with constant current source or the remote 2721B charge amplifier.
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