A state-of-the-art, rotary-disc atomizer driven by a permanent-magnet electric motor and supported by active magnetic bearings (AMB) was designed, fabricated, and tested as part of a spray-dryer system within a pharmaceutical-processing plant. The atomizing process imposed several challenges on the AMBs, including large, highly-dynamic rotor imbalances and large, quasi-periodic external radial impulses. Several design changes were systematically implemented to mitigate the effects of large rotor imbalances. A novel impulse detection and recovery system was introduced to alleviate the effects of external impulses. These changes, which have steadily improved the operability and reliability of the machine, are described here along with field test data.