The module,depth and material of Gears are calculated according to the stress of gear at each step. By life test of motor to produce the motor with low noise and enough life time. Gearbox can be assembled with DC motors, DC brushless motors and shade pole motors.
Selection of a geared motor:A geared motor is selected according to the required usable power output.
useableP(W)=           useableP(W)=
useableP(W)=               useableP(W)=
Selecting the reduction gear ratio:Two selection criteria may be applied.
* The first criterion concerns the required speed output of the reduction gear only. It is adequate for most applications and is easy to apply. Given that :
             N1= required speed of geared motor             B1=basic nominal speed of motor
* The second criterion concerns the required usable power output of the motor. The rotational speed of the motor is given by :
                                            
N = speed of motor(rpm)                  No = no loadspeed of motor(rpm)         
P = required output power(W)         Cd = start-up torque of motor(Nm)
this gives the equation:                                                
 In order to avoid using numbers less than 1 where the reduction ratio is concerned, the value 1/R is employed.
Due to the fact that it is always a reduction gear and not a "ultiplier" gear, there should be no ambiguity concerning the number used.