Index of content:
Volume 118, Issue 4, October 2005
- TRANSDUCTION 
118(2005); http://dx.doi.org/10.1121/1.2011155View Description Hide Description
The mechanical and electrodynamic parameters of a small, potentially inexpensive, moving-magnet electrodynamic linear motor are determined experimentally. Employing the formalism introduced by Wakeland, these parameters are used to predict the electromechanical efficiency of the motor. The transduction coefficient, , was observed to be a function of position. But as shown in the paper, the variation in with position has a smaller effect on the driver’s output power because is largest around the equilibrium position, where the piston velocity is also largest. By mechanical colinear joining of the armatures of two such motors, an electrodynamic load (dynamometer) is created to measure the efficiency as a function of energy dissipated in the dynamometer. The measured efficiencies are shown to be in good agreement with the predictions if a position-averaged effective transduction coefficient is introduced. Based on these results, this linear motor is judged to be an attractive power source in small electrically driven thermoacousticrefrigerator applications.