Transactions section: Preprint of corresponding pages from the current annual AIEE transactions volume

THE tapped-winding capacitor motor is used quite commonly to obtain a two-speed fan motor with a comparatively simple switching arrangement. With the open-end type of connection as shown in Figure 1, the high-speed connection gives a normal capacitor motor, and its performance under any load may be determined by calculation with the formulas of either the revolving-field theory or the cross-field theory. When a control winding is added to the already complicated capacitor motor circuits, the analysis by the usual methods becomes even more difficult, and the calculation more involved and tedious than ever. In the following discussion a method is presented for calculating the low-speed performance. This method while not absolutely rigorous, should give results well within the limits of variation of individual motors of the same design.