As an example, consider a person riding a bicycle, with the person acting like the electric motor. If that person tries to ride that bike up a steep hill in a gear that’s created for low rpm, she or he will struggle as
they try to maintain their stability and achieve an rpm which will permit them to climb the hill. However, if indeed they change the bike’s gears right into a velocity that will create a higher rpm, the rider could have
a much easier time of it. A continuous force could be applied with simple rotation being provided. The same logic applies for commercial applications that require lower speeds while keeping necessary
torque.
• servo gearbox inertia matching. Today’s servo motors are generating more torque relative to frame size. That’s due to dense copper windings, light-weight materials, and high-energy magnets.
This creates greater inertial mismatches between servo motors and the loads they are trying to move. Using a gearhead to better match the inertia of the engine to the inertia of the strain allows for using a smaller electric motor and results in a far more responsive system that’s easier to tune. Again, that is accomplished through the gearhead’s ratio, where in fact the reflected inertia of the strain to the engine is decreased by 1/ratio2.
Recall that inertia is the measure of an object’s level of resistance to change in its movement and its own function of the object’s mass and form. The higher an object’s inertia, the more torque is needed to accelerate or decelerate the thing. This implies that when the load inertia is much bigger than the motor inertia, sometimes it can cause extreme overshoot or enhance settling times. Both circumstances can decrease production line throughput.
However, when the electric motor inertia is bigger than the strain inertia, the electric motor will require more power than is otherwise essential for the particular application. This increases costs since it requires paying more for a motor that’s bigger than 
necessary, and because the increased power usage requires higher operating costs. The solution is to use a gearhead to complement the inertia of the engine to the inertia of the strain.