Abstract: Apparatus for controlling power transfer in an electrical induction device uses a controlled reactance to regulate the power transferred from an alternating current power source to a load without distorting or degrading the transferred power waveshape. The apparatus includes a power transformer having a power core and a primary coil and a secondary coil each encircling the power core. A number of control cores, separate from the power core, have associated control coils which are selectively short-circuited to provide the controlled reactance. The primary coil is arranged to encircle the control cores and coils and the secondary coil so that the primary coil is subject to the controlled reactance of the control cores.

Abstract: A noninvasive blood pressure measuring and recording system includes an inflatable cuff for encircling a portion of the human body, a pump for inflating and deflating the cuff for selectively occluding an arterial vessel, a detector for detecting flow variation through the arterial vessel as cuff pressure is decreased, and a recorder for recording cuff pressure values corresponding to the detected flow variation. The pump is a reversible single stroke sleeve diaphragm pump pneumatically coupled to the cuff and provides a selected, repeatable linear rate of pressure change for accurate, repeatable measurements through an automatically controllable motor operating at a selected constant speed to actuate the pump. A speed control changes the linear rate of pressure change in response to detected flow variations to enhance accuracy of measurement of selected variations, such as those identified with the systolic and diastolic pressures.

Abstract: A controllable power transferring device of the type used for controlling or regulating the application of A.C. electric power to a load by means of a reactance controlled by selectively short-circuiting a control coil with a controllable short-circuiting switch such as an SCR. The device employs a power transformer with a power core and a primary coil and a secondary coil each encircling the power core. A control core, separate from the power core, is encircled by the selectively short-circuited coil and is also encircled by one of the primary or secondary coils to subject that coil to the controlled reactance of the control core. By arranging the primary or secondary coil to encircle both independent cores, more efficient use is made of core and coil material, and more efficient controlled power transfer is obtained.

Abstract: A power transferring method and device of the controlled reactance type designed to regulate or control the application of alternating current electric power to a load. Reactance is controlled by using the signal to be controlled to develop a controlled magnetic flux in opposition to the reactive magnetic flux, the resulting flux cancellation effectively eliminating reactance. The device includes a reactance means with a core and a first coil around the core to be connected into the circuit in which power transfer is to be controlled. The opposing magnetic flux in the core is developed by a second coil around the core and having one end connected to one end of the first coil. Controllable means, such as an SCR, connect the other end of the first coil to the other end of the second coil to place the two coils in parallel. The coils are arranged on the reactor core so that parallel currents through the coils produce opposing magnetic fluxes in the core.