Abstract: A three-position actuating mechanism (10) for a transfer switch (11) is disclosed. The transfer switch is movable by the actuator (10) between a contact block (13) corresponding to a normal power source, and a contact block (14) interconnected to a standby or emergency power source. The actuator (10) has a pair of disk drives (22, 23) interconnected to solenoids (20, 21) by means of linkages (33, 34). The disk drives (22, 23) are interconnected to each other and to a driven disk (26) by means of a pin (30). Energization of the solenoids (20, 21) causes movement of the corresponding solenoid plunger (31, 32) and rotation of the disk drives (22, 23), so as to cause rotation of the contact crossbar (16) and transfer of the contacts (15, 18) between the two power sources.