Can you please explain the difference between Direct Current and Alternate Current? Also, what is the best way to describe the force on the armature -"torque" ?

Asked by Divya | 18th Sep, 2015, 09:17: PM

Expert Answer:

Direct current (DC)

Alternating current (AC)

It is the current of constant magnitude.

It is the current of magnitude varying with time.

It flows in one direction in the circuit.

It reverses its direction while flowing in the circuit.

It is obtained from a cell (or a battery).

It is obtained from an AC generator and mains.

The basic components in a motor are the armature (referred to as a rotor) and the field (i.e., stationary, also referred to as a stator). These two components magnetically interact with one another to produce rotation in the armature. 

The figure shows, the armature and the field are two separate circuits, next to each other to promote magnetic interaction.The armature has an integral part, called a commutator. The commutator acts as an electrical switch that switches the polarity of the magnetic flux to ensure that a "repelling" force taking place. The armature rotates as a result of the repelling motion created by the magnetic flux of the armature, oppositing to the magnetic flux created by the field winding.

The physical connection of voltage to the armature is accomplished by a device called brushes. Brushes are made of a carbon material that is in constant contact with the armature's commutator plates.
Torque: Torque is a measure of how much a force acting on an object causes that object to rotate. 

Answered by Faiza Lambe | 19th Sep, 2015, 05:22: PM

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