GLOSSARY OF TERMS

• alternating current (AC) - electrical current that reverses direction at a certain frequency. For example, alternating current from a wall socket in the U.S. reverses current at 60 Hz, or 60 cycles per second.
• armature - the rotating axle of a motor
• brushes - points where power source makes contact with rotating commutator.
• commutator - ring or similar object fixed to end of armature. Allows continuous contact with power source.
• direct current (DC) - electrical current that maintains a single direction.
• electromagnet - magnet created by coiling current-carrying wire, thereby polarizing the induced magnetic field.
  
• stator - the stationary part of the motor. Contains the armature and the external magnetic field it is immersed in.
• torque - a force acting on a moment arm. In this case, the force that causes the armature to turn.
• windings - coils of wire used to make electromagnets in a motor.