Two Pole Example Electric Motor

When giving presentations or displaying at shows I feel you can never have too many visual aids. On my website I had created a project article for the Simple Electric Motor but when demonstrating it is nice to have examples of more complicated electric motors. Awhile back I had purchased a 2-pole motor that was just made for demonstrations, it was large in size and completely open so you can see all the internal workings.  The polarity of the magnets is displayed and you can easily switch the magnets around to see what happens when polarity is reversed.  No assembly was required but I created a base to mount the motor, switch, and battery box to.

 

 

Although this electric motor is an improvement over the single coil / single magnet motor in my project article it did have drawbacks. First of all the motor will not start when the end of the wound wire poles are inline with the permanent magnets as seen below. You need to move the armature from this position with your fingers before switching on the electricty.

 

 

There is also a brief segment when the brushes will short across the commutator as seen in the picture below.