  Compact, ultra-high-speed self-bearing permanent-magnet motors enable a wide
scope of applications including an increasing number of optical ones. For
implementation in an optical setup the rotors have to satisfy high demands
regarding their velocity and pointing errors. Only a restricted number of
measurements of these parameters exist and only at relatively low velocities.
This manuscript presents the measurement of the velocity and pointing errors at
rotation frequencies up to 5 kHz. The acquired data allows to identify the
rotor drive as the main source of velocity variations with fast fluctuations of
up to 3.4 ns (RMS) and slow drifts of 23 ns (RMS) over ~120 revolutions at 5
kHz in vacuum. At the same rotation frequency the pointing fluctuated by 12
$\mu$rad (RMS) and 33 $\mu$rad (peak-to-peak) over ~10000 roundtrips. To our
best knowledge this states the first measurement of velocity and pointing
errors at multi-kHz rotation frequencies and will allow potential adopters to
evaluate the feasibility of such rotor drives for their application.
