I am using a bare copper wire to build a simple DC motor for a project and the motor is not working. Would the problem be because of the wire? I am using copper for the brushes and Aluminum foil for the split ring commutator, neodymium magnets of pull 16kg, and a 9V battery. Or can the problem be from the brushes? They are 0.41mm thick. Is a thinner sheet better and should the wire have a layer of insulation?