Primary Calibration of Accelerometers at NIST Using a Dual Coil Shaker
Beverly F. Payne, David J. Evans
Until recently, the primary calibration of accelerometers at NIST over a frequency range of 50 Hz to 5 kHz utilized three different shakers with separate measurement systems. With the development of the NIST supershaker and associated calibration system, this frequency range can be covered in its entirety using one test setup. Three independent primary vibration calibration methods consisting of fringe counting, minimum point, and reciprocity can now all be used on one shaker system. There is an overlap in the range of frequencies over which each of these three methods can be used. This gives added capability in that one need not rely on just a single calibration method. Uncertainty estimates associated with the new system when using these methods show improvements in the estimated uncertainty of accelerometer calibrations performed at NIST. Examples of both single-ended and back-to-back accelerometer calibrations are given along with estimated uncertainties.