How would you explain in short the working of a DC motor?

A simple DC motor, like one in a motorized remote control (RC) vehicle, works on a simple electromagnetic principle. The idea is that if you can generate a magnetic field in a coil on a rotor by applying a voltage, and you can set this field up to "buck" against a fixed magnetic field in the case or stator of a device, you can get the applied force to move the rotor. Further, if you can then change the polarity of the applied voltage to the coil as it moves and tends toward an alignment of the magnetic fields, you can get the rotor to rotate continuously. The torque delivered by the interaction of the generated and the fixed magnetic fields will not be linear, but will be sufficient to spin the rotor. The rotor will turn toward a point where the magnetic fields can be "aligned" with Norths to Souths. At a point "half way" through the rotation where the fields are coming into alignment, a set of contacts or brushes on an armature reverse the polarity of the applied voltage to the coil. This sets up a reverse current in the coil, and a reverse magnetic field around the coil. This again "bucks" the stationary field of the stator's permanent magnets. The rotor again responds to the torque generated by the interacting magnetic fields, and it rotates more. And again the commutator breaks the circuit to the coil in the rotor and reverses the polarity of the applied voltage. This process repeats, and the rotor is in continuous motion. Though there are variations on the theme, the simple idea delineated here is what makes the basic DC motor function. Use the links below to learn more.