Controllable power transferring device utilizing a short-circuited controlled reactance

A power transferring device of the type used for regulating or controlling the application of alternating current electric power to a load by means of a reactance controlled by selectively short-circuiting a control coil with a controllable short-circuiting switch, characterized by:

• a power transformer having a power core and primary and secondary coils each encircling the power core and arranged for connection respectively to means acting as a source of alternating current electric power and to means forming a load;
• a control core separate from the power core and encircled by the selectively short-circuited control coil;
• one and only one of the primary or secondary coils being arranged to encircle both the control core and the power core, thereby to subject that coil to the controlled reactance of the control core;
• the control core being arranged to subject the coil encircling both cores to essentially complete choking reactance without saturation of the control core when the control coil is open-circuited, thereby to substantially prevent power transfer between the primary and secondary coils;
• the control coil loading the control core with the small resistance of the control coil and switch when the switch is short-circuited, thereby to transfer power substantially unimpeded between the primary and secondary coils;
• whereby the control core and coil are enabled to efficiently control the transfer of power between the primary and secondary coils by selective opening and closing of the switch with little power dissipation occurring in the transferring device in either switch state.