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Likewise, people ask, how the direction of rotation of Barlow's wheel can be changed?
The pool of mercury is kept in between the two oppositepoles of a strong magnet. On passing current through the circuitthe wheel will begin to rotate due to the action ofthe magnet on the current. The direction of rotation of thewheel can be determined by applying Fleming's left handrule.
Secondly, why Barlows wheel does not work in AC?
Because the current down the spoke into themercury interacts with the permanent magnets in such a way to moveit in a particular direction. If the current was AC thespoke would just vibrate forward and backwards andnot have any net rotation.
Basically, theinteraction between the electric current and the magnet made thestar shaped wheel turn. The pool of mercury was electrifiedthrough the battery and one point of the star wheel wasdipped into it.