Compare the application of a DC and AC motor for two contrasting modern electrical installations.

An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this would be the conversion of mechanical energy into electrical energy and is done by an electric generator.

In normal motoring mode, most electric motors operate through the interaction between an electric motor's magnetic field and winding currents to generate force within the motor. In certain APPLICATIONS, such as in the transportation industry with traction motors, electric motors can operate in both motoring and generating or braking modes to also produce electrical energy from mechanical energy.

AC Motors are commonly run by an AC variable frequency drive, an AC electric motor operates by applying alternating current (AC) power to the electric motor. An AC electric motor consists of several parts but the main parts are the stator and rotor. In the other hand, DC Motors DC electric motors are powered from direct current (DC) power and are mechanically commutated machines. DC electric motors have a voltage induced rotating armature winding, and a non-rotating armature field frame winding that is a static field, or permanent magnet.

The AC electric motor’s stator has coils that are supplied with the alternating current and produces a rotating magnetic field. The AC electric motor’s rotor rotates inside the electric motor’s coils and is attached to an output shaft that produces torque by the rotating magnetic field. There are two different types of AC electric motors and each of them uses a different type of rotor. The first type of AC motor is called an induction motor (also known as an asynchronous motor).

DC electric motors use different motor connections of the field and armature winding to produce different speed and torque regulation. Unlike AC electric motors, DC electric motor speed can be controlled within the winding by changing the voltage applied to the DC motor armature, or by adjusting the field frame current.

An induction motor uses a magnetic field on the rotor of an induction motor that’s created by an induced current. The other type of AC motor is called a synchronous motor and rotates precisely at the supply frequency or on a sub-multiple of the supply frequency.

Most DC electric motors today are manufactured to be controlled with industrial electronic DC drives. DC electric motors are still used in many APPLICATIONS across the globe such as paper producing machines, and steel mill rolling machines.

AC and DC Motors DC motors are usually seen in applications where the motor speed needs to be externally controlled. AC motors work best in applications where power performance is sought for extended periods of time. All DC motors are single phase, but AC motors can be single phase or three phase.

AC and DC motors use the same principle of using an armature winding and magnetic field except with DC motors, the armature rotates while the magnetic field doesn’t rotate. In AC motors the armature does not rotate and the magnetic field CONTINUOUSLY rotates.

In some applications today, DC electric motors are replaced by combining an AC electric motor with an electronic SPEED CONTROLLER, known as variable frequency drives. DC electric motors are replaced with an AC electric motor and an electronic speed controller because it is a more economical and less expensive solution.

Found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives, electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as from the power grid, inverters or generators. Small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use. The largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, and so on.

The difference between AC and DC electric car motors, and which one will work best:

Direct current (DC) motors are the most popular choice for EV conversions, for a few good reasons. First, they are the least expensive and most readily available, and has enough power for a small or medium-sized car.

The DC Series electric motors are known for their high torque capacity from standstill. While combustion-style engines lack power when getting started, Applications such as diesel locomotive traction motors and drill motors (both of which are usually DC electric) help illustrate this feature. While torque is considered a benefit, though, continuous hill-climbing high-load driving with a DC motor is not ideal; AC motors do this much better. This is because DC motors have permanent magnets mounted on the inner surface of the motor housing. These magnets are able to provide high torque, but they don’t transmit heat well, leading to heat buildup in the windings.  DC continuous operating horse power is substantially less than peak horse power (HP).

Alternating current (AC) motors aren't used in DIY electric cars nearly as often as DC motors; it isn't because they don’t perform well. On the contrary, AC motors is better in many ways — including continuous power for hill climbing, regenerative braking, wide range, light weight and overall power. AC motors just tend to be a lot more expensive than DC. Why it’s so expensive? A few reasons why it’s expensive are: one of which is the fancy converter system that changes the direct current coming out of EV batteries into an alternating current. Another is the sophisticated exchange system that allows for regenerative braking. As mentioned previously, AC motors are more efficient, and when combined with regenerative braking they are a clear winner for distance applications.

The speed of DC motors is controlled using pulse width modulation (PWM), a technique of rapidly pulsing the power on and off. The percentage of time spent cycling the on/off ratio determines the speed of the motor, e.g. if the power is cycled at 50% (half on, half off), then the motor will spin at half the speed of 100% (fully on). Each pulse is so rapid that the motor appears to be continuously spinning with no stuttering.