Title :
A note on the response characteristics of the VACM compass
Author :
Patch, S. ; Beardsley, R. ; Lentz, S.
Author_Institution :
Courant Inst. of Math. Sci., New York Univ., NY, USA
Abstract :
Several simple laboratory experiments have been conducted to study the dynamic behavior of the vector averaging current meter (VACM) compass. These experiments demonstrate that the combined eddy current and bearing friction torque on the compass magnet is proportional to the angular velocity difference between the compass magnet and housing. This combined friction torque tends to critically damp the free oscillation of the compass as originally intended by the compass´s designers. Step-forcing experiments on the six compasses indicate all (undamped) resonant period of 3-5 s at 41°N. Periodic forcing experiments with one compass yield a more accurate determination of the resonant period of 4.0 s
Keywords :
flow measurement; oceanographic equipment; oceanographic techniques; VACM compass; angular velocity; bearing friction torque; compass magnet; direction determination; dynamic behavior; eddy current; measurement technique; orientation; resonant period; response characteristics; vector averaging current meter; Aluminum; Damping; Eddy currents; Equations; Friction; Magnetic levitation; Magnetic resonance; Sea measurements; Torque; Velocity measurement;
Conference_Titel :
Current Measurement, 1990., Proceedings of the IEEE Fourth Working Conference on
Conference_Location :
Clinton, MD
DOI :
10.1109/CURM.1990.110899
