Abstract: An apparatus and method for reducing certain harmonics in the output of static inverters. Static inverters which employ a switching device arranged in a bridge circuit to convert direct current power to alternating current power produce undesired harmonics in the output of the inverter. Harmonic neutralization techniques are further improved by the invention utilizing selective notching of the inverter pole voltage and a coordinate phase shift between the set of pole voltages produced by the individual inverters. The notch angles in the individual pole voltage outputs are chosen to minimize or eliminate specific undesired harmonics.

Abstract: A high voltage high power DC source includes a magnetic flux pole structure responsive to a high frequency, relatively low voltage source inductively coupled to the pole. Multiple AC to DC converters inductively coupled to the pole are connected in series, stacked relationship with each other, to derive the high voltage, high power DC output. Each stage includes a pair of oppositely wound planar coils on opposite sides of a printed circuit board. The printed circuits of the different stages are displaced from each other and a coil driven by the high frequency source.

Abstract: The switching power supply has sinusoidal or constant input current. The latter one results in best possible line and component utilizations at any time. The switching power supply comprises a first capacitor for storing a base voltage and second capacitor for storing output voltage. A first inductor is coupled between a first terminal and ground. A second inductor is coupled between a second and third terminals. A first switch selectively applies input voltage to the second terminal. A second switch selectively applies the base voltage to the third terminal. A first and second diodes are coupled to the first terminal and further respectively to the second terminal and first capacitor. A third and fourth diodes are coupled to the second capacitor and ground respectively. The third and fourth diodes are further separately coupled to the second and third terminals in either order.

Abstract: A current sharing circuit for each of a plurality of parallel coupled power conditioners, each current sharing circuit for each power conditioner having a filtering circuit responsive to a voltage signal representative of the input current to the associated power conditioner for providing an averaged signal indicative of the average load current for the associated power conditioner. The averaged signals for all of the current share circuits are summed at a summing node to provide a reference voltage signal indicative of the average load current for the parallel coupled power conditioners. Each current share circuit further includes a differential circuit for providing a difference signal indicative of the difference between the average load current and the averaged signal, and an output circuit for adding the difference signal with the associated power conditioner output voltage to provide a feedback signal for the error amplifier of the associated power conditioner.

Abstract: A dual state power system utilizing power drivers to switch an alternator from 12 volt to 24 volt charging. A 12-24 volt alternator regulator charges a 12 volt battery or a 24 volt battery depending on the position of a mode switch. The invention allows the use of one alternator/engine combination to charge either a 12 volt or 24 volt system. The invention uses a 12 volt mode priority to override a 24 volt charging mode. The 24 volt charging mode is interrupted to provide voltage to a 12 volt battery for a predetermined time period. A voltage controller drives a smart electrical current driver which controls the output of an alternator. A reset circuit determines from system parameters reported from system components whether the charging system to a reset error circuit whether or not the alternator is operating correctly. A sense lamp driver indicates to the user that the system is in a non functioning state.

Abstract: A voltage regulator generates an output voltage between an output line and an output reference voltage from an input voltage between an input line and an input reference voltage. The voltage regulator combines a self excited series resonant oscillator and a switching regulator control circuit. The self excited series resonant oscillator includes an oscillator circuit which produces an oscillating signal. The oscillating signal is rectified to produce a rectified signal. The rectified signal is filtered to produce the output voltage on the output line. The switching regulator control circuit switches the self excited series resonant oscillator on and off at a duty cycle which maintains the output voltage on the output line at a predetermined value.

Abstract: An apparatus and method is disclosed for an improved variable impedance transformer for controlling the power from an alternating input power source to a load in accordance with a direct current control signal. The invention comprises a DC control winding simultaneously wound about a plurality of saturable reactor cores and a plurality of AC power input windings simultaneously wound about a power core and each of the saturable reactor cores. A power output winding is wound about the power core for delivering power to the load. A low impedance equalizing winding is wound about the saturable reactor cores for shunting any resultant alternating voltage as a result of physical variations between the saturable reactor cores.

Abstract: A rectifier power supply automatically adjusts to operate over either of two separate ranges of AC line voltages by reconfiguring filter capacitors so as to charge the capacitor serially when operated over the higher range of voltages and to charge the capacitors separately over each half cycle when operated over the lower voltage range. A triac device, used to control charging of the capacitors, is selectively activated only during a small portion of each half cycle to minimize power consumption. The device includes a bridge rectifier circuit receiving an AC line voltage and supplying pulsating DC to the serially connected two filter capacitors. The triac is used as a switch and is connected between one input terminal of the diode bridge and a node point between the two capacitors. An AC line voltage range detector and triac control circuit responsive to the range detector causes the triac to conduct when the AC line voltage is detected within the lower range.

Abstract: A circuit for converting on d.c. voltage to another d.c. voltage including a transformer having a center tap and first and second end leads. A d.c. source voltage is connected to the center tap of the transformer. The end leads are connected to ground through first and second MOSFETs and to the gate of the MOSFET through which the other end lead is connected to ground such that the circuit is nominally self-oscillating due to transformer saturation. Current spikes may be minimized with a control circuit, consisting of an oscillator, a flip-flop, and first and second transistors, connected to the gates of the first and second MOSFETs. The control circuit turns the MOSFETS off prior to their natural oscillation turn off caused by transformer saturation. The circuit is particularly suited to operation with a low voltage d.c. source and low voltage MOSFETS.

Abstract: A starter motor including an electric motor (1) having an armature (1b) balanced in terms of rotation, thereby preventing the generation of a centrifugal force and its application to a bearing (8).

Abstract: This power supply system for a D.C. electrical load, such as an illuminated sign, is normally energized by batteries. A central processing unit monitors the battery voltage and when it falls below a predetermined magnitude, the central processing unit then activates a starter motor which cranks an engine coupled to it. The central processing unit also actuates a valve and fuel pump to pass fuel to the engine. The engine drives an alternator which produces A.C. voltage which is then rectified by aa rectifier to recharge the batteries. When the batteries are fully charged the central processing unit stops the engine. The central processing unit employs a microprocessor chip to control operations of the system.

Abstract: A piezoelectric actuator includes a pair of piezoelectric members which are oriented to shear laterally toward each other in the presence of an applied voltage. A hinge having translational members (which act similarly to a rack) and a rotating member (which acts similarly to a pinion) is attached to the top of the piezoelectric members with one translational attached to a respective one of the piezoelectric members. A driven member attached radially outward from the rotating member will then move through an arc when the piezoelectric members laterally shear. An object, such as a mirror, when carried by the distal end of the driven member, will then be actuated.

Abstract: A control system for controlling an inverter having a connector for connecting the output of the inverter to a load wherein a temperature sensing arrangement senses the temperature of the connector and a controller responds to the temperature of the connector for controlling the inverter in order to control the inverter output.

Abstract: A protection device for a power converter utilizing GTO thyristors. A reactor is connected in series with the switching elements to suppress the current change rates. A capacitor is connected to the reactor by way of a coupling diode to receive and store energy from the reactor. An overvoltage prevention device is connected in parallel with the capacitor to keep the voltage of the capacitor below a set value. A single protection device may be utilized with a polyphase converter or a multiplex converter, thus providing a compact low cost protection device.

Abstract: A power converter comprising a current-type inverter is disclosed, in which an output of a converter unit is applied as an input to the inverter unit through a DC reactor, and AC power is supplied to a load from the inverter unit. A ripple component of the DC input of the inverter unit is detected, and the switching elements of the inverter unit are controlled by modulation rate if they are to be subjected to PWM control, thus completing a sinusoidal waveform of the output of the inverter unit. Specifically, since the input to the inverter unit is allowed to contain a ripple, the DC reactor is reduced in size. The output of the inverter unit is a sinusoidal AC power containing no high harmonics and therefore the load is free of effects of high harmonics.

Abstract: A charging apparatus for a multiunit system includes a portable unit (101) and a base unit (103). The portable unit (101) includes first and second conductive contacts (119, 120) disposed on the portable unit (101) essentially opposite each other, and rechargable energy storage means (311) electrically coupled to the first and second conductive contacts (119, 120). The base unit (103) includes an indentation (124) formed in the base unit (103) and having a receiving surface shaped to receive at least a portion of the portable unit (101), first and second conductive protrusions (127, 129) extending outwardly beyond the receiving surface essentially opposite each other, and energy source means (131) electrically coupled to the first and second conductive protrusions (127, 129). The first and second conductive protrusions (127, 129) contact the first and a second conductive contacts (119, 120), respectively when at least a portion of the portable unit (101) is placed in the indentation (124).

Abstract: A noise-shielded transformer is constructed with a toroidal core having mounted thereon a secondary winding, a bifilar shield winding, a conductive plate, an insulating member, a high voltage winding, and a primary winding. The secondary winding is located inside the other windings, making the assembly work easier and increasing the noise shielding effect. Multiple shielding, by the bifilar shield winding and the conductive plate, increases the capacitance between the secondary winding and ground and decreases the capacitance between the primary winding and the secondary winding, so that the noise eliminating characteristic with respect to pulse-property noise and high frequency-property noise is enhanced substantially. It is also possible to obtain a grounding effect and a noise-bypass effect by connecting a resonance condenser from ground to one end of the bifilar shield winding.

Abstract: A power tool includes an internal wiring structure having a first terminal board secured to a commutator motor stator and a second terminal board releasably engaged with the first terminal board to electrically connect terminals on the first and second terminal board. The second terminal board includes first and second conductive resilient brush terminals respectively resiliently engaged with first and second conductive brush holders when the stator is installed in a housing of the power tool. Internal wiring of the power tool is thereby automatically completed upon installation of the stator in the housing.

Abstract: In a quarter-bridge circuit for high currents the total current is subdivided into a plurality of parallel current paths. In each current path a semiconductor component (5.1, . . . , 5.n, 6.1, . . . , 6.n) that can be turned off via a gate, a freewheeling diode (7.1, . . . , 7.n, 8.1, . . . , 8.n) located opposite a midpoint, and a clamping capacitor (9.1, . . . , 9.n, 10.1, . . . , 10.n) are arranged in parallel with the freewheeling diode (7.1, . . . 7.n, 8.1, . . . , 8.n) and the turnoff semiconductor component (9.1, . . . , 9.n, 10.1, . . . , 10.n) in such a way that the respective freewheeling path has as minimal an inductance as possible. Provided between a load terminal (3) of the quarter-bridge circuit and each midpoint of a current path is one inductor (L11.1, . . . , L11.n, L21., . . . , L21.n) each which limits the rate of current rise, so that a current rush caused by an operating delay does not overload the turnoff semiconductor component (9.1, . . . , 9.n, 10.1, . . . , 10.n).

Abstract: A circuit for reducing the commutation transient in a switch-driven (12) free-wheeling rectifier (20) applied to a load (10) via a continuously conducting energy conducting inductor (28), in which a further inductor (34) and diodes (32, 38) are interconnected with the switch-driven rectifier (20) to free-wheel recovered commutation energy from rectifier (20) when the switch is non-conducting. In other circuit variations temporary energy storage is aided by one or more capacitors (72) and additional diodes (52, 54, 80, 107, 122) during turn-on of rectifier (20), which energy recycled back into the circuit to minimize power dissipation and reduce circuit component heating.