Direct Current Motors. Physics 12 . Joke of the day:. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. Direct Current Electric Motor.
An electric motor has two basic parts:
The stationary part (external magnets, power source, brushes)
The rotating part of the electric motor is called the rotor.
Brushes attached to battery
While both A.C. and D.C. motors serve the same function of converting electrical energy into mechanical energy, they are powered, constructed and controlled differently. 1 The most basic difference is the power source. A.C. motors are powered from alternating current (A.C.) while D.C. motors are powered from direct current (D.C.), such as batteries, D.C. power supplies or an AC-to-DC power converter. D.C wound field motors are constructed with brushes and a commutator, which add to the maintenance, limit the speed and usually reduce the life expectancy of brushed D.C. motors. A.C. induction motors do not use brushes; they are very rugged and have long life expectancies. The final basic difference is speed control. The speed of a D.C. motor is controlled by varying the armature winding’s current while the speed of an A.C. motor is controlled by varying the frequency, which is commonly done with an adjustable frequency drive control. 2Published by Ohio Electric Motors: http://www.ohioelectricmotors.com/what-is-the-difference-between-an-ac-motor-and-a-dc-motor-673#ixzz2PFxVRFMG