ASA 127th Meeting M.I.T. 1994 June 6-10

2aEA2. Developments in electromagnetic (variable reluctance) transducers for the generation of low-frequency, high-power underwater sound.

Donald P. Massa

Massa Products Corp., 280 Lincoln St., Hingham, MA 02043

There is a need to develop improved methods for generating low-frequency, high-power sound in the ocean. Electromagnetic transducers can have many advantages over other transduction technologies in the design of transmitters to meet this need. An historical overview of various electromagnetic transducers that have been developed will be presented, including the 300 000-lb. megawatt array manufactured for project Artemis in the early 1960s. Several high-power, low-frequency electromagnetic transducer designs will also be discussed that can be fabricated by using multiple push--pull driver modules as building blocks to produce the final structure. They can be configured into a wide variety of different array configurations, including linear, planar, cylindrical, conformal, or volumetric. These transducers possess many desirable characteristics, including immunity to explosive shock damage; no corona problems because transducers use low voltage drive; mechanical Q<1 when array loaded; no temperature sensitive components; and linear responses with low distortion due to push--pull design.