A.C. and D.C. motors serve the same function of converting electrical energy into mechanical energy
They are powered, constructed and controlled differently. The most basic difference is the power source. A.C. motors are powered from alternating current (A.C.) while D.C. motors are powered from direct current (D.C.), such as batteries, D.C. power supplies or an AC-to-DC power converter. D.C wound field motors are constructed with brushes and a commutator, which add to the maintenance, limit the speed and usually reduce the life expectancy of brushed D.C. motors.
The AC motor commonly consists of two basic parts, an outside stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft producing a second rotating magnetic field.
Gear motors are mechanisms that adjust the speed of electric motors, leading them to operate at a certain speed. They are composed of a series of gears that make up a kinematic chain, working on a set of rotary parts
AC motors and gear motors include single-phase motors used with a single-phase AC power supply and three-phase motors used with a three-phase AC power supply. A single-phase motor can be operated by simply connecting it to a single-phase power supply via the supplied capacitor. A three-phase motor does not require a capacitor. All you need is to connect the motor directly to a three-phase AC power supply.
Most AC motors are induction motors. Induction motors are favored due to their ruggedness and simplicity. In fact, 90% of industrial motors are induction motors. So you will need one for that your project