there's no reason really as to why the superconductivity principle can practically make a dc-motor running as perpetual except during starting only (which needs input first). Perpetual in a sense that it can run indefinitely without requiring input current always as it becomes self-sustaining and able to run with ease even with loads.
but there are sceptics and nay-sayer or other savants and researchers who still say it is not possible ? Why, what's the reason ?
in my view, the resistance per se is actually (unit of which is the ohm) in fact the physical reaction of the material from the passage of the electrons (which constitutes current) per second flowing through the entire lenght of the conductive material which is proportionate to it's longitudinal dimension and inveresely to it's cross section and once this wire becomes superconductive, therefore no resistance at all, then the current flows indefinitely (ad infinitum) without losses. Then if that's the case, what remains is the inductance of the wire only as it is formed into a loop and the more the loop it increases the better the inductance and with this inductance (analogous to inertia) then as the electrical energy (current flow) is stored in the magnetic field and it does in fact supports the storage of the current in magnetic the flux. So, with the help of the permanent magnet's field flux and in reaction with this stored electrical energy in the magnetic flux of the wire loops as in the stator, then one in theory, can make the dc-motor run perpetually, as the rotor rotates (using permanent magnets)!, right ? So, now, why this can not be done or will not work ?