3. Choosing a single-phase motor

3.1 Comparison of single-phase and three-phase motors

Single-phase and three-phase motors are similar in construction, with the important difference that, in the single-phase motor, only two-thirds of the stator slots are generally used. As a result, the materials used in this motor are less efficient. Furthermore, for the same dimensions, the single-phase motor has lower performance than its three-phase counterpart and, in particular, has no starting torque, making it necessary to use a device to start it.

A priori, the three-phase motor is the obvious choice, unless you don't have a three-phase power supply, or you want to take advantage of the greater ease of installation of the single-phase motor. At present, these two reasons can only be found in the low-voltage...