The Use MEMS to Detect Vibrations Associated With Abnormal Scroll Compressor Operation
Abstract
MicroElectroMechanical Systems (MEMs) are silicon microchips that have both electrical and mechanical components. The mechanical components convert mechanical signals to electrical signals for further processing. The application of MEMs technology to compressors is being explored by the National Institute of Standards and Technology for the Copeland Corporation, a manufacturer of scroll compressors. This project investigates the use of MEMs to detect vibrations associated with abnormal scroll compressor operation. The mechanical component on the MEMs is a vibration sensitive micro-cantilever beam with an encapsulated piezoresistor. Results for circuit operability are presented and piezoresistive vibration sensitivities of various length cantilevers are determined. A model for the vibration sensitivity is developed using the dimensions and properties of the piezoresistive cantilevers. A testing technique is developed that can be used to determine sensitivity for any cantilever geometry. The vibration sensitivity model and experimentation are used to identify the most sensitive cantilever design. The value of the piezoresistive coefficient is shown to be 190. This study shows that sensitivity increases with beam length end frequency of vibration. The best length cantilever is 1.6 mm. A shorter length may be acceptable if a built-on amplifier is used.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 03, 2000
- Accession Number
- ADA392408
Entities
People
- Kenneth M. Roman
Organizations
- United States Naval Academy