For external faults, the restraining windings receive the total secondary current and function to
desensitize the operating winding, particularly at high currents. The effect of the restraint windings
is negligible on internal faults, since the operating winding has more ampere-turns and it receives
the total secondary current while the net ampere-turns of the restraint winding are decreased by
virtue of the opposite direction of current flow m the windings during an internal fault.