As far as I can understand, after inducing a current inside a superconducting ring or spire, the current keeps flowing into the ring "for ever". Is this correct? Since electrons have no "friction" against the superconducting lattice, does this mean that I can virtually accelerate them "indefinitely", thus inducing an "indefinitely" high current? I mean, if current is caused by electric force applied to electrons, and resistance is due to electrons friction against lattice, maybe they accelerate indefinitely as long as I apply the force? "for ever" and "indefinitely" of cours refer to ideal conditions; so what does it actually happen in real world? How much a current can I induce into a superconducting ring?