A motor's Kv rating refers to its RPM per volt (RPM stands for revolutions per minute—but you knew that one, right?). For example, a motor with a 2200Kv rating should spin at 2,200 RPM when powered by one volt. A 3500Kv motor would spin at 3,500 RPM at one volt. When comparing Kv, a bigger number means more RPM per volt, a lower number. A2212-2200KV Brushless Outrunner Motor Aircraft Spec:KV: 2200Max Efficiency: 80%Max Efficiency Low kv for higher voltage battery pack, eg/ 4S and above Brushless Motor KV To In a motor that is brushless, the commutation is For a servo motor, high torque means a mechanism is able to handle heavier loads For a servo motor, high torque means a.