This appears to be a 12-wire motor. There are provisions for wiring as Y for both 230 and 460 volts. There are also provisions for wiring as ∆ for both 398 (really, 400) and 796 (really, 800) volts.
We can ignore the ∆ options as those are generally not encountered in North America.
On such a motor, being wired as a 480 volt Y, there is a "star point" at T10, T11 and T12, where these are connected together, and connections between T4 and T7, T5 and T8 and T6 and T9.
As usual, the line is T1, T2 and T3.
To rewire such a motor for 240 volts, there is a second "star point" at T4, T5 and T6 and, additionally, there are connections between T1 and T7, T2 and T8 and T3 and T9.
Also as usual, the line is T1, T2 and T3.
The challenge, then, is to determine which of the twelve threaded studs are T1, ..., T12.
The nameplate states the motor is presently wired for 480 volts, and tracing the wiring should identify most of those terminals, with T1, ..., T3 obviously being the line.
The three copper or brass bars appear to be there for the purpose of connecting T4 to T7, T5 to T8 and T6 to T9, for 480 volts.
It would appear that the additional jumpers are there for the purpose of making a "star point".
Only testing, using a DMM in continuity checking mode, can say for sure.