Brian, the 52Y is actually referred to as the anti-PUMP relay. This circuit will prevent the breaker from reclosing if the close signal is held on and the breaker either trips free or receives the trip signal after the close. It is designed to prevent the breaker from cycling open-close-open-close (ie pumping) if the operator holds the close in the on position.
By the way, the standard is the ansi C37.2 and can also be found in the IEEE red book.
Bruce