Differences Between AC and DC Electric Motors.

An electrical motor converts electrical energy into mechanical energy in the form of torque (rotational energy). There are two types of motors, direct current (DC) and alternating current (AC), which differ both in the type of electrical energy they use and how they generate torque. DC motors were invented earlier, but are less commonly used today. AC motors have a simpler design and are used in most appliances and industrial equipment.

Structure

• Both AC and DC motors contain two essential components: a stator and a rotor. An electrical current creates torque when it moves within a magnetic field, according to Faraday's Law. In a DC motor, the rotor receives a direct current and a commutator reverses the current as the rotor rotates in a stationary magnetic field created by a permanent magnet in the stator. In an AC motor, the rotor receives an induced alternating current, and the stator is an induced magnetic field.

Mechanics

• The advantage of DC motors is that you can easily adjust their speed simply by increasing the voltage. However, DC motors have a more complex design, requiring brushes to transfer energy to the moving parts and a commutator to periodically reverse the voltage. These parts will wear out over time due to friction and eventually need to be replaced. AC motors have a simpler design, but they work at fixed speeds and cannot operate at low speeds.

Usage

• Due to their variable speed, DC motors can be used for both low-power and high-power applications. However, due to their higher cost and need for replacement parts, they are typically only used to power devices that require a variable power input, such as hybrid cars and certain toys. AC motors are cheaper to make and are compatible with the majority of modern appliances which have an AC energy source.