Shock and Vibration Testing: Are Electrodynamic Shakers Superior to other Shakers?

Electrodynamic shakers are similar in principle construction to loudspeakers -- they convert electrical current flow into mechanical force over the widest frequency range with minimal spectral distortion of the input waveform. This moving “voice coil ” configuration offers a large test-article attachment surface with a lightweight moving mass.

The shaker's voice coil is attached to a suspended aluminum support and test article attachment structure called the "armature". The shaker's armature is guided so that it's allowed to move relatively easily in the direction of the generated force and have the highest stiffness possible in all other directions. In this respect, shakers are primarily unidirectional vibration devices. It's very important that the armature suspension be stiff in all transverse directions to minimize any lateral deflections caused by load attachment that could cause lateral armature coil deflection.

Electrodynamic shakers utilize normal current/force motor principles to generate vibrations. Electrodynamic force is inherently linear, and offers wider bandwidth with lower noise and harmonic distortion than mechanical- or hydraulic-based vibration generation. Electrodynamic shakers may be air-cooled, eliminating requirements for oil and water used in conjunction with other types of shaker cooling.

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