Description of a DC motor

Electric motors turn electricity into motion by exploiting electromagnetic induction. A current-carrying loop that is placed in a magnetic field experiences a turning effect.A simple direct current (DC) motor is illustrated here. ABCD is mounted on an axle PQ. The ends of the wire are connected to a split ring commutator at position X and Y. The commutator rotates with the loop. Two carbon brushes are made to press lightly against the commutators.

The motor features a external magnet (called the stator because its fixed in place) and an turning coil of wire called an armature ( rotor or coil, because it rotates). The armature, carrying current provided by the battery, is an electromagnet, because a current-carrying wire generates a magnetic field; invisible magnetic field lines are circulating all around the wire of the armature.

The key to producing motion is positioning the electromagnet within the magnetic field of the permanent magnet (its field runs from its north to south poles). The armature experiences a force described by the left hand rule. This interplay of magnetic fields and moving charged particles (the electrons in the current) results in the magnetic force (depicted by the green arrows) that makes the armature spin because of the torque. Use the slider current I to see what happens when the flow of current is reversed. The checkbox current flow and electron flow alows different visualization since I = d(Q)/dt and Q= number of charge*e. The Play / Pause button allows freezing the 3D view for visualizing these forces, for checking for consistency with the left hand rule .

Options

"Real 3D","Isometric","Front View","Side View","Top View" allows different views in 3D and different perspectives

"Fz show","Fz hide","Ix show","Ix hide","By show","By hide" allows force, current and magnetic field to be shown and hidden

"split ring","no split ring" allows split ring or no split ring for pedagogical explorations of when if scenario

"FLHR show","FLHR hide" allows a Fleming's Left-hand Rule to appear on the wire to support students doing their own visualizations using their own left hand

"Labels show","Labels hide" allows texts A,B,C,D etc to appear to support discussion of current flow and specific wire clearly

It is very important to learn to interpret other forms of representations such these animations which are similar to what engineers used for visualization and simulation.