Phase-sensitive LVDT transducer testing system

A system has been developed to measure mechanical and electrical parameters of ultralinear STA0.05% (full scale) nonlinearity! displacement transducers of the linear variable differential transformer (LVDT) type. From these measurements, transducer pretravel, over travel, maximum percent nonlinearity, null voltage, and half-range output voltage can be determined. The system measures transducer stylus position with a precision digital micrometer. Corresponding output/input voltage ratio (transfer ratio) data are measured using a phase-sensitive, AC bridge circuit. From these measuremerts the maximum percent nonlinearity of an LVDT transducer is determined with an accuracy of plus or minus 0.024% (full scale) for a 0.200-inch (5.08-mm) transducer. (auth