Several home appliances, especially kitchen appliances, and various portable tools use another type of single-phase motor, called universal, whose operating principle is completely different from the induction motor.
The name of the universal electric motor comes from the fact that it can operate under both AC and DC power. In fact it is a DC series motor.
It is an electric motor of variable speed, with low speeds for large torque and high speeds for small loads.
The starting conjugate is also high and therefore is commonly used in small appliances, such as electric drills and sanders, requiring high torque, and in blenders, vacuum cleaners and centrifugal pumps, which require high speed.
They are usually manufactured for powers up to 3/4 HP. For powers above a few CV, these motors do not work very well in alternating current, therefore, a great friction occurs in the brushes what results in a decrease of the yield and the factor of power.
The stator is a set of protruding poles with coils wound on them and the rotor consists of a winding distributed in grooves and connected in series with the coils of the stator (armature). https://www.mrosupply.com/electrical/extension-cords-reels/cord-reels/2208276_lg3050-143-9_reelcraft/