Most of the homopolar motor demonstrations have a limitation that they cannot work with any DC source other than battery. The battery does not last very long, and needs frequent replacements.
The model shown here overcomes this limitation. It consists of a single turn coil made of thick copper wire. Lower end of the coil is supported on copper tape placed on a washer made of insulating material. Upper end of the coil surrounds a neodymium magnet, which in turn is covered with copper tape. This arrangement is set up in a frame for mechanical support.
Although the magnet itself is made of electrically conductive material, the copper tape provides better electrical contact. In addition, wires can be easily soldered to the copper tape. In this setup, these wires are connected to an AC to DC converter. The coil starts rotating as soon as the converter is switched on.
A precaution required here is that the converter should be able to limit its output current. Alternatively, a series resistor may be used for current limiting.
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