Criterion of selection between a AC and a DC motor advantages and the disadvantages of them?
Since you are asking for the criterion of selection, here it is.. AC motors have two coils: an outer coil to produce magnetic field, and an inner coil to produce counter electric field. DC motors have an outer magnet, and an inner electric field. DC motors need DC voltage supply, and since all of the household supply is AC conversion is needed (thus making DC more inefficient, although the loss is minor) AC motors give better torque than similar DC motors. Since AC motors have two ciols, the magnetic field between the two colis can be adjusted to give maximum efficiency or power (something that DC motors cannot do)
DC motors work when powered by batteries (car starter motors?). AC motors run on house current (window fans?). Selection of a suitable motor often depends on the nature of the load (horsepower required) and the power source that is available available.
