Electrical Motors

Exibit A: Electric Motor

Electrical motors, just like Legos, make the world go round.  But seriously, they do make the world go round.  The earth spins on a giant motor, you didn't know that?  Anyways it would probably be a good idea to tell you about the basic types of motors: AC and DC.  AC, or alternating current, motors are driven by AC power and can power anything from a refrigerator to HVAC system in Brown Building.  Typically, AC motors are used for constant speed applications.  DC, or direct current, motors are driven by DC power and are typically used to power anything that operates on a battery.  Robots, automobile starters, and the playstation 3 controller are all powered by batteries and require DC power to drive their motors.  One significant advantage of DC motors is their ability to provide a high starting torque, approximately 6x that of AC power.  This large starting torque is need for various applications, such as starting your car on a cold winter morning.

Below is a video demonstration of how the internal components of a DC motor work together.  It is a bit technically but honestly the only way to understand a motor is get technical.  Here is the untechnical side of a motor:  I plug the electrical cord into the wall and it starts spinning. Done.

For the techs (do not read if you do not have an engineering degree, it will only melt your mind): So basically an electric DC voltage is applied across the green +- potential, which induces a current in what is called the rotor.  This current thereby creates a magnetic field which interacts with a permanent magnetic field provided by the stator in blue.  This interaction between the two magnetic fields results in a force which caused the rotor to spin a specific direction.