Characteristics of pumped air of spray dryer rotary atomizers depend on their design and operating variables. By measuring the wheel vacuum pressure and required power pump air together, the air-pumping characteristic of a spray dryer rotary atomizer was studied. The experiments were conducted using three types of atomizer wheels: vaned, pin type, and multihole. Parameters of pumped air contain shear power, air-pumping power, and differential pressure, which were measured for three wheels in different air gap and atomizer speed. The rotary atomizer speed range was from 7000 to 27,000 rpm and the air gap varied from 0.5 to 1.5 mm. Results indicated that by increasing the wheel speed, shear power, air-pumping power, and differential pressure increased for all wheels. In addition, by increasing the air gap, shear and air-pumping power increased and differential pressure decreased for all wheels.