Design of the a.c. servomotor

The modern servomotor is required to meet a stringent performance specification. This specification is shown to present basic design restrictions. In addition, manufacturing limitations and techniques provide extra restrictions on the design. The approximate design will be modified towards an optimum which is defined by quantities detailed in the specification. A general theory can be developed in terms of primary machine dimensions which will provide performance equations. These equations allow comprehensive design curves to be computed, which exhibit the effect of variation of all the normal design parameters on motor performance. The final design will be chosen by the designer from a range of possibilities made apparent from the curves. This choice will be dictated by such practical considerations as ease of construction, cost and availability of construction materials.