A novel axial position sensor is presented. The sensor offers a unique combination of advantageous properties not found collectively in other axial position sensing solutions. These include ability to work in dusty environments and in many working fluids, low sensitivity to temperature as well as external electrical and magnetic fields, good linearity over a large displacement range, large intrinsic gain, easy integration into a machine, robustness to the variations in parameters of the external wiring, simplicity of the signal processing electronics, sufficient frequency bandwidth and a commonality of used elements with radial magnetic reluctance position sensors. This paper describes the operating principle, test procedure and test results of the constant-flux edge sensor in both single-sided and differential configurations. Presently the sensor has been successfully integrated into several commercial machines and extensively tested under various operating conditions.