The Right Dipole has a normal short between windings inside the magnet. This makes changing the current in the magnet problematic. The solution was to slow the rate of change for the current in the magnet. The concern is that a faster rate will tear the magnet windings apart. In the immortal words of Joe Mitchell, "If you're not happy with how it moves, we can leave it where it is. We don't HAVE to move the HMS." Or something to that effect.