Understanding Electric Motor Coils and Direction: Exploring DC Motor Theory

[XxsithlordxX]

Homework Statement

Why must the coil in an electric motor kit be wound in only one direction?
Why must the current change direction every 180 degrees in the motor?

Homework Equations

No relevant equations. Just a simple answer.

The Attempt at a Solution

NI-Prentice Hall DC Motor Theory states that The armature (rotor) of a DC motor has coils of wire wrapped around its core. The ends of each coil are terminated at commutator segments located on the left end of the shaft. The brushes make contact on the commutator to provide current for the armature.

 

[Simon Bridge]

NI-Prentice Hall DC Motor Theory states that The armature (rotor) of a DC motor has coils of wire wrapped around its core. The ends of each coil are terminated at commutator segments located on the left end of the shaft. The brushes make contact on the commutator to provide current for the armature.

So far so good ... but how does that mean the coils all have to be wound the same way?

If you made the coil with, say, 20 turns clockwise and another 20 anticlockwise - how would that affect it's performance compared with 40 all the same way?

 

[CWatters]

Perhaps think about why a motor rotates in the direction it does.

 

[Simon Bridge]

@XxsithlordxX: how did you get on?

 

[rezeew]

The coil in an electric motor kit must be wound in only one direction because this allows for a consistent flow of electricity through the coil. If the coil were wound in multiple directions, it would create a chaotic and inconsistent flow of electricity, which would result in an inefficient and unreliable motor.

As for why the current must change direction every 180 degrees in the motor, this is due to the design of the commutator and the brushes. The commutator is a rotating switch that allows the current to flow through the armature in a specific direction. As the armature rotates, the brushes make contact with different segments of the commutator, causing the current to change direction every 180 degrees. This ensures that the magnetic fields produced by the current in the coil are always pushing in the same direction, resulting in a continuous rotation of the motor. If the current did not change direction, the motor would not be able to rotate and perform its intended function.