Single-phase motors are known due to the fact that their field windings are connected directly to a single-phase source. In this way, single-phase induction motors have emerged as a natural alternative to three-phase induction motors in places where we do not find three-phase power, such as buildings, homes, offices, mechanical workshops and even rural areas. https://www.mrosupply.com/hydraulics-and-pneumatics/hose-reels/2793427_ca33122-l_reelcraft/
Because they have only one phase of power, they do not have a rotating field like three-phase electric motors, but rather a pulsating magnetic field. This factor does not guarantee that they have starting torque, taking into account that magnetic fields are induced in the rotor in line with the stator field, for example. To solve the starting problem, auxiliary windings are used, dimensioned and distributed in a manner capable of creating a second dummy phase, thereby allowing the formation of the rotating field required for starting. We only explain its use for low power, from 1 to 2 KW. Amongst the various types of single-phase electric motors, squirrel-cage rotor motors are emphasized for their simplicity of manufacture and also for robustness and less maintenance.