Calnetix Technologies Awarded Patent for Novel Eddy-Current Position Sensor

The United States Patent and Trademark Office (USPTO) has recently awarded a new patent to Calnetix Technologies for its novel eddy-current position sensor, invented by Principal Research Engineer Alexei Filatov.

“We have developed a unique eddy-current position sensor that allows measurements of both the radial and axial positions of a rotor in an active magnetic bearing (AMB) system using a single sensor target,” said Filatov. “The existing AMB eddy-current position sensors measure rotor positions as the gap changes between a sensor target surface normal to the rotor axis and the sensor. In most cases, such a target surface does not exist and needs to be added to the rotor, complicating the design and negatively affecting rotordynamic margins. In contrast, our new sensor allows high-fidelity axial position measurements of a target that ‘slides by’ the sensor placed next to its outer circumference. The same target can also be used for the radial position measurements.”

The new sensor delivers a combination of the following advantageous properties not found collectively in prior technologies:

  • “Slide-by” operation for the axial position measurements – no sensor target surface normal to the rotational axis is needed.
  • Single target for both axial and radial position measurements.
  • Simple and robust construction.
  • Twisted wire pairs are used, which are much easier to route through machine interfaces than the coaxial cables required for other eddy-current sensors. Excellent linearity over a wide displacement range.
  • High operating temperature potential (>225°C).
  • Approximately 200kHz operating frequency offers an excellent compromise between the sensor bandwidth and the electronics complexity.
  • Well suited for high-volume production.

“The latest patent is evidence of Calnetix’s commitment to the importance of research and development,” said Vatche Artinian, CEO of Calnetix. “We have a remarkably strong team of engineers, who have developed highly innovative products that are driving energy efficiency and productivity in various industries. With every invention and every patent, our researchers and engineers are paving the way for Calnetix’s continued growth.”

About Calnetix Technologies

Calnetix Technologies, LLC (“Calnetix”), headquartered in Cerritos, Calif., is focused on Innovation That Drives Industries®. The company specializes in high-performance, high-speed motor generators and best-in-class advanced magnetic bearings and control systems. Calnetix’s patented, underlying technologies, which have been in use since the company’s inception in 1998, have made Calnetix a world leader in the design and production of high-speed machines. The company’s overall technology portfolio and system integration capabilities have led to development and production contracts with industry leaders and the start of many successful subsidiaries that focus on unique niche markets. For more information, please visit