Abstract: A gapped resonant current transformer that has a pre-determined gap in a split-core. The invention eliminates the need for a magnetic flux shunt between the primary and secondary windings. Further, the sensitivity to the clamping force holding the two halves of the split-core is reduced as well as temperature effects on the core. Finally, excess heat is removed from overload (saturation) by circulating power back into the line.

Abstract: A switching power supply (30) uses a transformer 37 having a first primary winding (38A) and a second primary winding (38B) wrapped around the same core (52, 53) but wrapped around opposite sides of the core (52, 53). One of the ends from each of a pair of secondary windings (61, 62) are electrically connected together to form a conventional transformer center tap and the remaining ends of the secondaries (61, 62) become conventional transformer end taps.

Abstract: An electronic circuit in which resistors R.sub.0 . . . R.sub.n+m are coupled in series with fusible cut-outs Q.sub.0 . . . Q.sub.n+m and in which at least one fusible cut-out Q.sub.n+1 . . . Q.sub.n+m is bridged by an additional resistor R.sub.n+1 ' . . . R.sub.n+m '. Each of the fusible cut-outs Q.sub.0 . . . Q.sub.n+m can be blown from a conductive to a non-conductive state. The total conductance Y.sub.total of the electronic circuit can thus be adjusted by targeted blowing of individual ones of the fusible cut-outs Q.sub.0 . . . Q.sub.n+m.

Abstract: In a magnetron drive apparatus a high frequency voltage converted and outputted by a frequency converter is inputted to a primary winding of a transformer and a high voltage power outputted from a secondary winding of the transformer is rectified and supplied to an anode of the magnetron and a power outputted from a heater winding of the transformer is supplied to a heater of the magnetron. The magnetron drive apparatus comprises a magnetic flux leakage device disposed in a magnetic path formed by the primary and secondary windings of the transformer and increasing a leakage magnetic flux in the magnetic path; and a device for winding the secondary winding and the heater winding therearound in a position opposite the primary winding with the magnetic flux leakage device arranged therebetween.

Abstract: A magnetic amplifier including a magnetic core having a primary leg, a secondary leg, and a control leg. A primary winding is wound about the primary leg of the magnetic core for generating a non-saturating magnetic AC flux in the magnetic core, and a secondary winding is wound about the secondary leg of the magnetic core. A control winding for conducting DC current is wound about the control leg of the magnetic core for controlling as a function of the DC current, without saturating the magnetic core, the reluctance of the control leg relative to the reluctance of the secondary leg. By controlling the relative reluctance, the amount of magnetic AC flux coupled to the secondary winding is controlled, thereby relative reluctance, the amount of magnetic AC flux econtrolling the output voltage provided by the secondary winding.

Abstract: A variable transformer, reactor having a core combining at least two complete core elements wiht a common yoke; primary winding divided into two independently fed sets of phase coils wound in opposite direction, arranged on symmetrical legs of core elements and separated by the common yoke; secondary winding with each phase coil divided into two wound in opposite direction portions carried by symmetrical core legs, adjacent to the primary coils and separated by common yoke. The secondary short-circuited reactor winding is reduced to at least one close loop member with loop portions separated by the common yoke. The single, polyphase apparatus has at least one primary coil per set that includes a controllable device in circuit relation therewith to enable control of one primary coil relative to the other, either in current magntidue or in current phase shift. The controllable device being either a silicon control rectifier, triac or transistor.

Abstract: The transformer comprises a three-limbed magnetic core having two outer limbs each defining a central air gap. Two windings, an alternating current one and a direct current one, are wound around each outer limb. Primary and secondary windings are disposed on the center limb, the primary one being supplied with alternating current from a source, and the secondary one supplying with alternating current an external load. The two alternating current windings are connected in series and supplied with alternating current by the source, possibly through an additional winding wound around the center limb, while the two direct current windings are connected in series and supplied by the current in the alternating current windings rectified through a diode bridge. The current in the two direct current windings induces a magnetic flux in a closed circuit defined by the outer limbs.

Abstract: An electric power apparatus, namely a variable inductor comprising a magnetic core provided with a center limb and two outer limbs all having first and second ends. The first ends are interconnected through a first common point of the magnetic core, and the second ends through a second common point of this core. Two primary windings disposed respectively around the two outer limbs are connected in series and supplied with an alternating current, while two control windings also connected in series are respectively superposed to the two primary windings. The alternating current of the primary windings is rectified through a diode bridge for supplying with direct current the control windings.

Abstract: A control system for driving a variable speed AC motor employing a fixed frequency AC power source, combines pulses representative of a desired slip frequency with pulses of a frequency proportional to the speed of the motor. The combined pulses are employed with a speed command signal to set a threshold which determines the fraction of each cycle of the AC primary power which is fed to the motor. In addition, the speed and slip pulses are employed to direct the AC power to specific ones of the windings of the motor to thereby create a rotating magnetic field in the induction motor. An array of silicon-controlled rectifiers does the actual gating and an SCR protect circuit ensures that transfer of control from one SCR to another is inhibited until all current ceases to flow in an SCR being extinguished. A forced commutation circuit forces the extinction of all current remaining in the last conducting SCR feeding a motor winding at the transfer time from that motor winding to the next.

Abstract: Variable ratio transformer constructed around a control transformer comprising: two closed magnetic circuits each constructed around a ferromagnetic core. An alternating current magnetic field circulates in the first core and a direct current magnetic field circulates in the second core. The two circuits are located so as to define at least two common magnetic spaces in which the fields are superposed orthogonally. Around the first core is wound a primary winding, a secondary winding and, for a specific application in a three-phase circuit, a tertiary winding. A conventional transformer can be associated with the control transformer to reduce the load supported by the control transformer. The variable ratio transformer according to the invention can be used as a static balance compensator.

Abstract: An adjustable current source comprises a choke (1) and a capacitor (2) whose reactive impedances are equal at the frequency of a variable voltage source (3), as well as a load current matching and adjusting unit made as a magnetic amplifier (4). Some outputs of the choke (1), the capacitor (2) and a primary winding (6, 7) of the magnetic amplifier (4) are coupled to respective phases of the variable voltage source (3). Other outputs of the choke (1), the capacitor (2) and the primary winding (6,7) of the magnetic amplifier (4) are joined in a star connection. The secondary winding (9, 10) of the magnetic amplifier (4) is coupled to the load (11). The control winding (13) of the magnetic amplifier (4) is coupled to a constant voltage source (14).

Abstract: A voltage regulator using a saturable transformer comprises a transformer having a primary and secondary windings, an AC power source for supplying the primary winding a fluctuating alternating current, and a rectifier connected to the secondary winding for rectifying an AC voltage derived therefrom to produce a DC output voltage. The transformer includes a core having four legs and two common portions magnetically joining the four legs, and a control winding supplied with DC control bias from a control circuit. The primary and secondary windings are wound on the first and second legs and the control winding is wound on the first and third legs.

Abstract: A variable leakage transformer having a closed main magnetic path and a closed submagnetic path having a leg common with said main magnetic path. A primary winding is wound on said common leg, and a secondary winding is wound on said main magnetic path. The magnetic flux in the common leg is controlled by other control windings which are connected to a control DC power source. The primary winding has two portions, and one of them is closely coupled magnetically with the secondary winding in order to improve the output waveform. By controlling the magnetic flux in the sub-magnetic path, the leakage of the flux induced by the primary winding from the main magnetic path to the sub-magnetic path can be controlled; thus the coupling between the primary and the secondary winding, and conduction period in each cycle of the AC output voltage are controlled. The control of the conduction period in each cycle provides control of the power transmitted from the primary winding to the secondary winding.