What happens / why do motors stall?

[maclaren]

When I was reading this thread I was doing great till somone mentioned "back EMF" and then I got confused. So I decided to go out and look for more info on the back EMF phenomena. So I went to google and found very useful and very CONCISE which, in my opinion, all the replies to this thread singly lacked. This is what I found:

-EMF stands for Electro Motive Force or Voltage (being it's more common name).
-Back EMF occurs when a magnetic field is collapsed.
-This collapse of magnetic field cuases a spark (easily visible in AC motors).
-The voltage of the power source to the motor creates a positive potential which is then neutralized by the negative potential of the spark or back EMF when the brushes lose contact with the commutator contacts.
-The flow of electrons that cause the motor in this case to move is from positive to negative the spark that occurs is in the opposite direction from negative to postivie hence the back part of back EMF.

Useful Website

I don't know If this clarified anything for others but it sure did for me. Thanks for your time.