[9][10][11] The main[citation needed] benefits of a direct-drive system are increased efficiency (due to reduced power losses from the drivetrain components) and being a simpler design with fewer moving parts.
Major benefits also include the ability to deliver high torque over a wide range of speeds, fast response, precise positioning, and low inertia.
[12][13] The main drawback is that a special type of electric motor is often needed to provide high torque outputs at low rpm.
High-speed motors with speed reduction have relatively high inertia, which helps smooth the output motion.
In high-speed motors, this effect is usually negligible, as the frequency at which it occurs is too high to significantly affect system performance; direct-drive units will suffer more from this phenomenon unless additional inertia is added (i.e. by a flywheel) or the system uses feedback to actively counter the effect.