ABSTRACT
This chapter shows that product design can proceed by trial and error, by repeated analysis, or by synthesis. Design methods for each of these items are known or may be devised from the knowledge already in the engineer's tool kit. The task of the designer is to decide every detail of these devices so that the device may be made in such a way that the specifications are met. The way in which a designer proceeds to determine design parameters depends on the designer's success in establishing various types of model. For some devices it is impossible to establish mathematical models, or at least models that are simple enough that their manipulation is tractable. The mechanical engineer had to determine the forces required to open and close the breakers, translate those forces into the torques on the cam and its shaft, determine the torque losses in the speed reducer. The supply voltage of 120 volts was selected for convenience.
