In an electric motor......((see more))?

Question

In an electric motor, how does the electric current in the wire get turned off as the coil spins??

the coil meaning the armature

Answer 1

Sounds like you're talking about an A.C. induction motor. Current is fed to both the field and the start capacitor. when the motor starts up, a centrifugal switch opens the stationary switch at the top casing. Opening the stationary switch turns off current to the start capacitor, which isn't needed to keep the motor running. Only the field current is needed to keep the motor running.

Answer 2

Assuming your are talking about a DC motor....

A DC motor has a commutator mounted on one end of the armature. The commutator is a series of conductive strips with each lead of the coil connected to its own counductive strip.

Electrical connection to the armature coils are made through carbon brushes (One posiive the other negative) which are mounted on opposite sides of the communtator. The brushes are held against the commutator by springs . Upon applying power the shaft starts to rotate due to the magnetic field generated by the current flow through the coil. As the shaft rotates the conductive strips of the commutator move along the fixed brushes . Eventually each commutator strip moves out from under the brushes all together momentarily stopping current flow. As inertia cause the shaft to continue to rotate the conductive strips make contact with the brushes again re-establishing power flow through the coil but this time in the opposite direction. (The shaft has only rotated 180 degrees sofar) In other words the commutator reverses (Switches)current flow through the armature coil for every 180 degrees of revolution of the shaft. There is a momentary period just as the switching ocurrs when the power flow through the coil is interrupted.

Answer 3

You will need to be more specific. Is it an AC or DC motor. What wire, the armature or field coil?