Abstract: A high temperature magnetic amplifier, which utilizes the nonlinear properties of square loop magnetic cores to achieve very large amounts of both voltage and power amplification. By combining square loop, grain-oriented magnetic materials with high temperatures along with high temperature packaging approaches, high temperature long lifetime components can be produced. The high temperature magnetic amplifier is used as a building block to develop high temperature versions of operational amplifiers, comparators, voltage regulators, timers, counters, modulators, motor starters, servo systems, converters, inverters, power switches and many other devices.

Abstract: A method and current sensor arrangement for measurement of a primary current in a primary conductor which is magnetically coupled to a secondary conductor via a ferromagnetic core, with a voltage of a specific amplitude being applied to the secondary conductor, such that a secondary current flows for remagnetization of the ferromagnetic core, and the secondary current is measured during the remagnetization of the core, in order to obtain a first measured value. The voltage polarity is then reversed such that a secondary current flows for renewed remagnetization of the ferromagnetic core, and the secondary current is measured during the remagnetization of the core, in order to obtain a second measured value. The primary current is calculated as a function of the first and of the second measured value, with the polarity reversal being carried out at least once at a time which occurs before that time at which the ferromagnetic core reaches its saturation magnetization.

Abstract: A DC current sensor has a detecting core with a plurality of detecting core members adapted to be divided in a circumferential direction for receiving the lead wire. A pair of annular exciting cores on one of said detecting core members formed of saturable magnetic material has a core intersection inter-connected perpendicularly to the circumferential direction of said detecting core members, and are disposed oppositely in spaced relation with said detecting core members to magnetically saturate a portion thereof by a magnetic flux produced substantially in the perpendicular direction against a magnetic flux in the circumferential direction, produced by the DC current flowing through said lead wire being detected, and to interrupt a magnetic path by the magnetic flux in the circumferential direction periodically. Exciting coils are wound around the exciting cores in negative-phase excitation.

Abstract: A method and circuit for measuring direct and high duty factor current in a conductor (1) with minimal interference with the operation of a monitored circuit. Current flow in the conductor is magnetically sensed with a transformer T1 having a primary winding connected electrically in series with the conductor (1). The transformer T1 is driven into saturation during a first time interval and brought out of saturation during a second time interval. After the transformer T1 is brought out of saturation, an output signal is provided which is proportional to the flow of current in the conductor (1).

Abstract: A magnetic amplifier package (1) comprises a diode rectifier (6) and a plurality of saturable reactors in the form of toroids (2) having cores (3), gate windings (4) and control windings (5). The diode rectifier and the saturable reactors are located within a housing (7) of the package. The housing has an inlet (18) and outlet (19) for cooling fluid and a passage (20) within the housing for circulating coolant between the inlet and the outlet for cooling both the diode rectifier and the saturable reactors. The magnetic amplifier package is compact, lightweight and efficiently cooled to facilitate its use in aircraft.

Abstract: A variable electrical current in a first winding on a magnetizable core produces a magnetomotive force in the core. A second core winding produces an opposing magnetomotive force digitally adjustable periodically by a third core winding, a pair of switches and a flip-flop coupled to a center tap for alternately closing such switches when triggered to opposite states. The flip-flop is triggered between opposite states when the third winding current reaches a particular magnitude. In each cycle, the time differences for producing the particular magnitudes and the opposite polarities are dependent upon the remanent core flux. Such time differences are counted digitally upwardly and downwardly for opposite polarities. The second winding current is adjusted digitally in each cycle in a direction to minimize such count. The magnitudes of successive adjustments may be compared periodically by adaptive tracking techniques to control the magnitudes of subsequent adjustments.

Abstract: A low power consumption current transducer utilizes a saturable core reactor which includes a pair of opposed gate windings and a control winding. The control winding of the saturable reactor is arranged to receive the current to be measured. A square wave generator is connected to the gate windings via a transformer with the primary winding of the transformer connected across the square wave generator and the secondary connected in series with the gate windings of the reactor. A full wave rectifier is connected to the gate windings and a resistor is connected across the rectifier to provide a DC voltage thereacross representative of the current flow through the control winding. A DC power supply is provided to supply power to the square wave voltage source.

Abstract: A magnetic amplifier employing a single four-legged ferrite core having orthogonally disposed through holes in the core. Biasing is provided of the magnetic core so as to provide operation in the non-linear parts of the core's hysteresis cycle. A first coil on the ferromagnetic core has an AC excitation signal applied thereto and a second coil on the core is wound orthogonally to the first coil and is adapted to have an output signal derived therefrom. A control or input current in a third coil is used to unbalance the magnetic bridge formed by the four legs, so as to produce a mutual inductance different from zero between the first and second coil. The biasing may be provided by a fourth coil or by permanent magnet means.

Abstract: A current measuring system includes three toroidal magnetic cores. The first core has a non-linear B-H characteristic and being adapted for operation in and between its saturation ranges of its B-H characteristic. The second and third cores are adapted for operation in their substantially non-saturating range of their B-H characteristics. The first core is coupled in a flux oscillator configuration to provide a first error signal representative of low frequency flux changes in the core. The first core and the second core each have noise cancellation windings which are shorted in a manner cancelling noise. A high frequency sensor winding on the third core provides a second error signal representative of intermediate and high frequency flux changes in that core. A feedback network combines the first and second error signals to generate a bucking current which is coupled by way of bucking windings on all three cores.

Abstract: A single-ended switching circuit is constituted by a primary winding of a transformer, a switching circuit connected between the primary winding and a DC power supply and on-off operated with a predetermined cycle and also with a predetermined "on" period and a resonance capacitor connected in parallel with the primary winding. A magnetic amplifier, a rectifying element and a choke coil are connected in series between a secondary side circuit of the transformer and the load. The magnetic amplifier includes a saturable reactor which is held saturated during a half cycle of the voltage induced in a secondary winding of the transformer and remains unsaturated during the other half cycle of the voltage.

Abstract: In an apparatus having a saturable magnetic core, a control winding wound on the magnetic core and supplied with a D.C. voltage in accordance with a desired phase angle, and an output winding wound on the magnetic core and supplied with an A.C. voltage through a load resistor, whereby the firing phase of a thyristor is controlled by a voltage across the load resistor, an additional winding is wound on the saturable magnetic core to detect the saturation of the saturable magnetic core by a rapid drop of a voltage across the additional winding. When the saturation is detected, the magnitude of the A.C. voltage applied to the output winding is increased. The phase angle characteristic of the magnetic phase shifter is determined under a low voltage condition prior to the saturation of the magnetic core, and after the saturation a high voltage is applied to the load resistor.

Abstract: A direct current detecting device is disclosed in which two pairs of saturable cores are provided so as to enclose a conductor carrying a direct current to be measured. On each of the saturable cores, a bias winding, a feedback winding and an output winding are wound. First and second output circuits are provided, each connected with a pair of output windings and each including two closed current paths consisting of the output winding, a common load, a common A.C. supply source and a diode. The diodes function to allow the greater one of current flows of the two closed paths to be passed through the common load. An amplifier is connected to receive the difference between output signals of the two output circuits. The output of the amplifier is supplied to the feedback winding whereby the magnitude of the feedback current becomes a function of the magnitude of the current flowing through the conductor.

Abstract: An improved signal isolator including two nonlinear circuits having nonlinear voltage-to-current characteristics, in which an input network is formed by connecting one of the nonlinear circuits in series with the primary winding of a transformer, and an output network is formed by connecting the other nonlinear circuit and an averaging circuit in series with the secondary winding of the transformer. A pulse signal is applied to the input network, the output network or the tertiary winding of the transformer to develop an output signal corresponding to the input signal while the input network and the output network are isolated from each other with respect to direct current.

Abstract: A switching current amplifier for stepping motors utilizing a square hysteresis loop transformer to measure the motor winding load current directly, to determine the high and low switching points in reference to the position command signal, to compare the motor winding current to the determined switching points and to provide a switching signal to switch the output devices of the amplifier when the motor winding current reaches the switching points. The square hysteresis loop transformer is constructed to have a high common mode signal rejection.

Abstract: A magnetic amplifier sensor for measuring the magnitude and polarity of a DC current flowing in a line includes a pair of saturable cores, each having a primary and secondary winding mounted thereon. The primary coils are connected in series and a portion of the DC current component to be measured is diverted to a shunt circuit which includes the primary windings. The secondary coils are connected to a push/pull type of AC source so that the flux levels in the cores operate in a drive/reset mode. A DC current in the primary winding causes a variation in the absolute magnitude of the flux levels of the two cores as a function of the time constant of the shunt circuit so that during the drive interval one core saturates before the other.

Abstract: A magnetic amplifier having two saturable reactor cores with a separate excitation winding on each connected in series opposition, a common control winding and a common output winding, is adapted for use as a low level signal transducer by exciting the separate excitation windings in push-pull mode through a center tapped transformer, and including at least one diode in series with a load resistor connected to the output winding. A resistor in series with the output winding and load resistor is connected between the center tap of the excitation transformer and the connection between the two excitation windings of the saturable cores. This series resistor provides a return current path for the output winding and allows the excitation windings of the saturable cores to operate as primary windings of transformers.

Abstract: A system for detecting an output of a controllable semiconductor device includes a controllable semiconductor device, a magnetic amplifier to which an output of the semiconductor device is fedback to control the semiconductor device, and a monitor device for monitoring an output of the magnetic amplifier. The monitor device serves for determining that the output of said semiconductor device exceeds a predetermined level, when the output of the magnetic amplifier is in a remanent output region of the magnetic amplifier.

Abstract: A magnetic phase shifter control system comprises a magnetic phase shifter for producing an output signal in accordance with a control command at a predetermined amplification degree, a circuit for suppressing the output signal of the magnetic phase shifter to a level lower than a predetermined level on command, and a circuit for reducing the amplification degree of the magnetic phase shifter when the suppressing circuit is operative, whereby a delay for response due to a dead time which the magnetic phase shifter inherently has is eliminated.

Abstract: A control circuit comprises two series-connected pairs of saturable reactors, the two pairs being connected in parallel between a supply line and a load. Between one pair of reactors are connected two back-to-back diodes, the center tap of which is connected to the common point of the other pair of reactors. The difference between the voltages across the reactor main windings causes feedback which increases the magnetization of the cores and reduces further the impedance of the low impedance windings.

Abstract: A magnetic amplifier having a magnetic core in the shape of a hollow cylinder is provided with a gate winding comprising series-connected coaxial conductors passing through the center of the hollow core.

Abstract: Disclosed is an isolation amplifier, wherein a DC input signal is applied to the primary winding of a saturable reactor, the secondary winding of which is coupled with an oscillating circuit so as to supply the secondary circuit with a high-frequency current, and then the current flowing through the secondary winding is applied to a feed-back type low-pass filter, with which an output signal proportional to the DC input signal is extracted from the current flowing through the secondary winding.