We present results of an experiment with a 15.4-mm-dia, 150-mm-long rotor that uses HTS bearings for levitation and rotates in vacuum at kHz rates. Bearing losses are presented as a function of rotor speed up to a frequency of ${\rm f}=1681\ {\rm Hz}$ . For ${\rm f}>80\ {\rm Hz}$ (bearing resonances are at 28 and 41 Hz), the rotational drag increases monotonically with frequency up to a maximum at $\sim$274 Hz, then decreases monotonically with frequency. For ${\rm f}>160\ {\rm Hz}$, the rotational deceleration may be well represented by the term ${\rm B}+{\rm A}({\rm f}/{\rm f}_{0})/[1+({\rm f}/{\rm f}_{0})^{2}]$, where B and A are constants and ${\rm f}_{0}$ is the frequency at the drag peak. The frequency dependent term may be interpreted as the circumferential inhomogeneity of the PM interacting with the flux-flow resistivity of the HTS. At higher speeds, the frequency-dependent term is governed by the skin depth and becomes proportional to $1/{\rm f}^{1/2}$.