Patent ID: 8443673

Claim:
A method for measuring vibrations comprising: disposing one or more coils within a flux gap created between a plurality of ferromagnetic masses, wherein at least two of the plurality of ferromagnetic masses have an inner magnetic pole separated from one another by the flux gap, and wherein the magnetic polarity of each inner magnetic pole is similar to the magnetic polarity of the inner magnetic pole on the opposite side of the flux gap; measuring voltage generated on the one or more coils in response to changing magnetic flux arising from motion of at least one of the ferromagnetic masses; and generating an indication of vibrations based at least in part on the measured voltage, wherein disposing the one or more coils comprises disposing the one or more coils within the flux gap between the at least two ferromagnetic masses and wherein a portion of the one or more coils are within a region bounded between inner surfaces of the at least two ferromagnetic masses.