The most commonly used single-phase motor is that which employs an auxiliary starting coil in series with a suitable capacitor for that use, connected in series with a centrifugal switch, and called auxiliary phase or starting auxiliary coil BX Cogged V-Belts. The motor consists of two more coils, called main coils or working coils. The auxiliary coil is only traversed by electric current at the start of the motor and when the motor reaches approximately 85% of the value of its nominal speed through the centrifugal force generated by the rotation of the rotor causes the breaker contact to open, interrupting the current that circulates on the auxiliary coil.
Like three-phase motors, single-phase motors are designed to work in two different voltages, such as 110-220 V or 220-440 V. It allows some flexibility in this voltage, for example, the windings can work in the range of 110 to 127 V no problem. The connections must be made in such a way that the tension in the windings is always the lowest among those specified on the motor plate. The lag between the voltage and the current is obtained through the capacitor, helping the motor to obtain a high starting torque.