Abstract: A standard, unmodified induction motor starts with reduced input current, energy consumption and mechanical stress and is further protected from AC power source "phase loss", excessively low or high voltage or a locked-rotor condition during start-up or any subsequent moment while running when its stator winding is energized from a sine wave source through a signal-responsive wave modifier operative to control the portion of each cycle of the sine wave which is coupled from said source to the stator winding.

Abstract: A standard, unmodified AC induction motor has its stator winding energized from a sine wave source through a signal-responsive wave modifier operative to control the portion of each cycle of the sine wave which is coupled from said source to the stator winding. An improved motor current demodulator, responsive to efficiency-related parameters and excessive stator winding inrush current each time said current increases from zero, produces signals for controlling the wave modifier, thereby to maintain optimum motor efficiency with varying motor loads and power source variations, and the signals also control a motor protector circuit which inhibits said wave modifier thereby to deenergize said stator winding under excessive input current conditions, excessive motor temperature or a potentially damaging combination thereof.

Abstract: A standard, unmodified AC induction motor has its stator winding energized from a sine wave power source through a signal-responsive wave modifier operative to control the portion of each cycle of the sine wave which is coupled from said source to the stator winding. Load detecting means, comprising a comparatively small AC generator coupled to the rotor of the motor, produces a control signal, varying with variations in the load on the motor, for controlling the wave modifier to increase the field density of the stator winding with increases in load on the motor, and to decrease the field density of the stator winding with decreases in said load.

Abstract: A Direct Current electric motor comprises a stator consisting of a plurality of coils interconnected to one another, and a plurality of gate controlled solid state rectifiers responsive to forced commutation below a particular rpm and self-commutation above said rpm which are connected to the junctions of the coils for selectively conducting current into and out of the stator coil junctions in dependence upon which of said rectifiers is rendered operative. This produces a plurality of stator poles which are angularly displaced from the poles of the rotor of the motor and which shift in position as the rotor rotates. A plurality of trigger assemblies are provided for controlling the energization of the various gate electrodes, each of said trigger assemblies comprising a pick-up coil which forms a portion of a frequency selective circuit whose resonance frequency varies in dependence on the position of a magnetic element that is moved relative to the pick-up coils as the rotor rotates.

Abstract: A standard, unmodified AC induction motor has its stator winding energized from a sine wave source through a signal-responsive wave modifier operative to control the portion of each cycle of the sine wave which is coupled from said source to the stator winding. A motor current demodulator, responsive to efficiency-related parameters of the inrush current to the stator winding each time the current in the stator winding increases from zero, produces a control signal for the wave modifier, which signal varies with a decrease in motor operating efficiency below the maximum inherent efficiency of the motor to increase the field density of the stator winding in response to increases in motor load and to decrease said stator field density in response to decreases in said load and/or to maintain the most energy-efficient stator field density at rated motor loads when the voltage magnitude of the sine wave source increases or decreases from its nominally rated magnitude.

Abstract: A standard three phase induction motor starts with all three of its input connections connected to the three phase power line. Two of these connections are through triacs which remain continously conducting below said motor's particular most energy-efficient speed, which is above about 95% of synchronous speed. This assures full starting torque and undiminished overload handling capability. The triacs, in response to a control signal, may open the circuits over a sufficiently wide portion of the sine wave input voltage to substantially maintain said particular efficient speed under all rated load conditions. To assure smooth operation and maximum energy savings, the two triacs conduct differently at very light motor loads. The DC control voltage which determines the operation of the triacs is generated by a frequency discriminator circuit which receives its information from a load detecting device that is frequency modulated by load/speed related properties inherent to induction motors.

Abstract: A standard, unmodified AC induction motor has its stator winding energized from a sine wave power source through a signal-responsive wave modifier operative to control the portion of each cycle of the swine wave which is coupled from said source to the stator winding. Load detecting means, comprising a comparatively small AC generator coupled to the rotor of the motor, produces a control signal, varying with variations in the load on the motor, for controlling the wave modifier to increase the field density of the stator winding with increases in load on the motor, and to decrease the field density of the stator winding with decreases in said load.