[Steve D]

The wrap protects the coil windings and the terminations of the fine coil wire to the hookup leads. When I rewound my field coil I re-used the paper band and secured it with a few layers of friction tape.  Friction tape holds securely and looks original.

Typically field coils are not secured to the pole piece and are free to rotate. Once you disconnect the field coil hookup wires you should be able to rotate the coil to gain access to the start lead. If the break is at the finish wire connection you can unwind a few turns to get enough wire length to re-solder the connection.  My field coil from a RCA V-210 was 1100 ohms and had 10,000 turns of 34AWG wire so a few turns will not matter. 

If the break is at the start wire, hopefully there is enough wire lead left to re-solder it. It is almost impossible to remove turns from inside the coil. If the break is internal then the field coil will have to be re-wound which will require removing the cone/voice coil, pressing the pole piece out with an arbor press and rewinding it.  This will become quite a chore and perhaps it might be better to locate a replacement speaker or use a permanent magnet type with a 10H or so choke to replace the field coil for ripple filtering.

Here is a link to a thread showing my field coil re-winding:

https://philcoradio.com/phorum/showthread.php?tid=19722

Good luck,

Steve D