What are at least two disadvantages to using single-phase motors?

When single-phase motors are used, they will be limited to relatively low horsepower and low torque load requirement applications.Single-phase induction motors are larger per horsepower, draw more current to generate the same horsepower, they present an unbalanced load to the electrical distribution system, and they are more complicated than three-phase motors.The most complicating factor of single-phase induction motors over three-phase induction motors, is that they require additional auxiliary windings to operate.These additional mechanical parts in single-phase induction motors simply present more things that can go wrong with the motor, which causes them to be less reliable than three-phase induction motors.