In my eyes This looks like a gyro of some sort, What purpose could it have had? It was partly installed on my boat which has a spartan level of electronics. :
MD52A/B Magnetic Compass Fluxgate Sensor - Marine Data Systems
Fluxgates used as compasses. (a) Illustration showing how the signals... | Download Scientific Diagram
Fluxgate Compasses, Part 1 – Context and principles