How exactly do motors and generators work by using magnetic fields?

[abcd]

So I know if you move a charge in a magnetic field it induces voltage and hence a flow of charge is created which is current. ( Please correct me if I'm wrong). But that's pretty basic right. However, I'm having trouble understanding the use of split rings in the functioning of a motor. I would like anyone to give me a good explanation of how motors and generators actually work using the magnetic fields.

Thanks a bunch in advance.

 

[Baarken]

Split rings or commutator are used to reverse the direction of direct current, see the picture 1 below how it is done.

Why do we want to change the direction of the current? If we use the right hand rule (third picture) on the conductor that is to the right inside the magnetic field in picture 1, we get a force pointing down (see picture 2).

Similarly if we use the right hand rule on the left conductor in the magnetic field we get a force pointing up (remember to point your finger in the right direction of the current, since it has changed now compared to the other conductor). This results in a net torque trying to rotate the coil clock wise.Now let's see what happens after our coil has rotated 180 degrees. If we again apply right hand rule, observe from picture 2 that we now get a net torque trying to rotate our coil counter clock wise, which is opposite as before.

As a result we use commutators to change the direction of current, so that we get a torque trying to rotate one direction only and not change after it has rotated 180 degrees. Try it yourself using the right hand rule and see the effect of changing the direction of the current after rotating 180 degrees.

FIGURE 1:

FIGURE 2:

FIGURE 3: Charge or current moving in a magnetic field results in a force, direction is given as shown in figure blow. Right hand rule explained: Index finger in the direction of current, middle finger in the direction of magnetic field and then your thumb is pointing in the direction of the force.

EDIT:
Animations are perfect when you are trying to understand the basics of electric motors, for a general understanding of two common motor types (DC motor and induction motor) see these videos:




I hope my response did not get to messy.

 

[tech99]

In distinction to a commutator, split rings do not have a reversing action. They just make the connection to the rotating armature, and are used with alternators, where we are happy to have an alternating output.

 

[abcd]

Thank you so much, both of you. I learned a lot.
Thanks for helping out:) I wish my teacher made it this clear! haha

 

[Baarken]

If you are interested in calculating e.g. the magnitude of the force see this:

Source: http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/forwir2.html