how do dodgems work?

[LIZMOO]

How do fairground dodgems or bumper cars work?

[Skids]

You may have noticed that the 'floor' they run on is metal and that each car has a big long aerial type thing that touches a wire mesh suspended above them.  Each car is powered by an electric motor.  An electrical current is supplied to the wire mesh from a generator.  The aerial type thing is an electrical pick-up that transmits the current to the car's motor, hence the sparks.  The circuit is completed by a metal earthing brush that is in contact with the metal floor which is in turn connected to the negative side of the electrical generator.

[jetgriff]

Power is commonly supplied by one of two methods:

The oldest and most common method uses a conductive floor and ceiling, each with a separate power polarity. Contacts under the vehicle touch the floor while a pole-mounted contact touches the ceiling, forming a complete circuit.
A newer method uses alternating strips of metal across the floor separated by insulating spacers, and no ceiling grid.[2] The alternating strips carry the supply current, and the cars are large enough so that the vehicle body can always cover at least two strips at any one time. An array of brushes under each car make random contact with whatever strip is below, and the voltage polarity on each contact is sorted out to always provide a correct and complete circuit to operate the vehicle.

File:Autotamponneuse.oggPlay media
A ride in a bumper car, short video clip

The metal floor is usually set up as a rectangular or oval track, and graphite is sprinkled on the floor to decrease friction