Perhaps the most apparent is to increase precision, which is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the guts distance of the tooth mesh. Sound can be suffering from gear and housing materials as well as lubricants. In general, be prepared to pay out more for quieter, smoother gears.
Don’t make the mistake of over-specifying the electric motor. Remember, the insight pinion on the planetary should be able deal with the motor’s output torque. Also, if you’re utilizing a multi-stage gearhead, the result stage should be strong enough to absorb the developed torque. Obviously, using a more powerful motor than required will require a larger and more costly gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, result low backlash gearbox torque can be a linear function of current. So besides safeguarding the gearbox, current limiting also protects the motor and drive by clipping peak torque, which may be anywhere from 2.5 to 3.5 times continuous torque.

In each planetary stage, five gears are at the same time in mesh. Although it’s impossible to totally get rid of noise from this assembly, there are several methods to reduce it.

As an ancillary benefit, the geometry of planetaries fits the form of electric motors. Thus the gearhead can be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are usually more expensive than lighter duty types. However, for rapid acceleration and deceleration, a servo-grade gearhead could be the only sensible choice. In such applications, the gearhead could be seen as a mechanical springtime. The torsional deflection caused by the spring action adds to backlash, compounding the consequences of free shaft motion.
Servo-grade gearheads incorporate many construction features to reduce torsional stress and deflection. Among the more prevalent are large diameter output shafts and beefed up support for satellite-equipment shafts. Stiff or “rigid” gearheads tend to be the most costly of planetaries.
The kind of bearings supporting the output shaft depends upon the load. High radial or axial loads usually necessitate rolling element bearings. Small planetaries can often get by with low-cost sleeve bearings or other economical types with fairly low axial and radial load capability. For bigger and servo-grade gearheads, durable result shaft bearings are usually required.
Like most gears, planetaries make noise. And the faster they operate, the louder they obtain.

Low-backlash planetary gears are also available in lower ratios. Although some types of gears are generally limited to about 50:1 or more, planetary gearheads lengthen from 3:1 (solitary stage) to 175:1 or even more, depending on the number of stages.