Some of the larger generators have stator windings that are cooled by water circulating
through the windings. If the flow of cooling water is impeded or stopped for some reason,
the winding will quickly overheat. The cooling water is circulated by water pumps, which are
backed up by standby pumps.
Flow detectors placed in the water line monitor the adequacy of the coolant flow. If the
flow is reduced for any reason, these detectors can start the standby pump. If this restores the
normal flow, no further action is taken, but if not restored within I minute, the turbine and
generator are tripped sequentially, starting with the turbine and then the generator [4).