As an example, look at a person riding a bicycle, with the individual acting like the motor. If see your face 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 balance and achieve an rpm that will allow them to climb the hill. However, if indeed they shift the bike’s gears into a acceleration that will create a higher rpm, the rider could have
a much easier time of it. A continuous force can be applied with smooth rotation being supplied. The same logic applies for industrial applications that want lower speeds while preserving necessary
torque.
• Inertia complementing. Today’s servo motors are producing more torque relative to frame size. That’s because of dense copper windings, lightweight materials, and high-energy magnets.
This creates greater inertial mismatches between servo motors and the loads they want to move. Utilizing a gearhead to raised match the inertia of the electric motor to the inertia of the load allows for using a smaller motor and outcomes in a far more responsive system that’s simpler to tune. Again, that is accomplished through the gearhead’s ratio, where the reflected inertia of the load to the electric motor is decreased by 1/ratio2.
Recall that inertia is the measure of an object’s resistance to improve in its motion and its own function of the object’s mass and shape. The higher an object’s inertia, the more torque is required to accelerate or decelerate the thing. This implies that when the load inertia is much larger than the electric motor inertia, sometimes it could cause extreme overshoot or increase settling times. Both conditions can decrease production range throughput.
On the other hand, when the engine inertia is larger than the load inertia, the electric motor will require more power than is otherwise necessary for this application. This improves costs because it requires having to pay more for a engine that’s bigger than 
necessary, and because the increased power usage requires higher operating costs. The solution is to use a gearhead to match the inertia of the engine to the inertia of the load.
Servo Gearbox, the right selection for you.