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Fundamental Measurements in Gravitational Physics Using Precision Rotations: I. Motivations and Unprotected-Rotor Results

George R Jones Jr1, R C Ritter1 and George Thomas Gillies2

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Decay time constants for magnetically-suspended rotors undergoing inertial spin-down have been measured at room temperature. Bearing-rotor interactions have been studied and evidence found that there is a driving mechanism capable of accelerating or decelerating a rotor with a moment of inertia of ≈1100 g cm2 at the 10-14 W level. The complicated rotor decay structure suggests that there exist unfavorable rotational frequencies at which mode coupling exists and leads to unavoidably large levels of angular momentum dissipation. The length of the rotors (≈20 cm) also produces a pendulum motion which at times results in ambiguities in the spin-down data due to interference with the normal operation of the optical-lever timing system.


PACS

84.50.+d Electric motors

06.30.Ft Time and frequency

06.30.Gv Velocity, acceleration, and rotation

06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Subjects

Electronics and devices

Instrumentation and measurement

Dates

Issue 4 (October 1982)

Received 13 April 1982



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