Abstract: An apparatus for controlling the output and torque of a synchronous alternator has a controlled bridge rectifier operable off synchronous for rectifying the alternating output and establishing a desired phase relationship between the alternating voltage and alternating current of the output winding. Phase locked loop control may be employed for establishing and maintaining a desired phase relationship to control the output and torque.

Abstract: An electric power generation system having two main sources of ac power comprises a first and a second main power conversion and distribution unit (MPCDU1, MPCDU2), each electrically coupled to one of the sources of ac power. The MPCDUs controllably supply ac electric power to an associated main distribution bus and additionally convert that power to a second type of power. This second type of power is supplied to an associated secondary distribution bus and to a converted power output. The system also includes an auxiliary source of ac power and an auxiliary power conversion and distribution unit (APCDU) which is electrically coupled to the auxiliary source. The APCDU controllably supplies ac electric power to a ground service distribution bus and additionally converts that power to a second type of power which is then supplied to an associated secondary distribution bus and to a converted power output.

Abstract: A programmable autosynchronizer for use with a system having generator and bus voltages and having a breaker circuit for connecting the generator and bus voltages to each other. The autosynchronizer synchronizes the frequency and phase of the generator and bus AC voltages by controlling the generator voltage. A microprocessor compares the frequencies of generator and bus voltage signals, the microprocessor generating a proportional difference signal having a parameter representative of a proportional difference in frequency between the generator and bus voltage signals. The proportional correction range extends within the synchronization range. The microprocessor permits a sync signal when the frequency difference of the frequencies of the generator and bus voltage signals is within the synchronization frequency range. A first output circuit responsive to the proportional difference signal provides a correction signal to the generator for varying the frequency of the generator.

Abstract: An autosynchronizer for use with a system having generator and bus voltages and having a breaker circuit for connecting the generator and bus voltages to each other. The autosynchronizer synchronizes the frequency and phase of the generator and bus AC voltages by controlling the generator voltage. A microprocessor compares the frequencies of generator and bus voltage signals, the microprocessor generating a proportional difference signal having a parameter representative of a proportional difference in frequency between the generator and bus voltage signals. The proportional correction range extends within the synchronization range. The microprocessor permits a sync signal when the frequency difference of the frequencies of the generator and bus voltage signals is within the synchronization frequency range. A first output circuit responsive to the proportional difference signal provides a correction signal to the generator for varying the frequency of the generator.

Abstract: A power inverter for use in the system interconnection of a direct-current supply with a commercial alternating-current supply includes an inverter circuit and a filter circuit. Feedback signals affecting the frequency of an output to be produced by the inverter circuit are taken from the filter circuit having frequency response characteristics such that the phase angle is reduced to 0.degree. at three frequencies consisting of a higher frequency, lower frequency and commercial frequency, the last of which lies halfway between the first and second. Under the normal condition, the frequency of the output produced by the inverter circuit is equal to the commercial frequency. In the event of a power failure or power cut in the commercial alternating-current supply system, deviation from the commercial frequency is caused by the characteristics of the filter circuit.

Abstract: An Uninterruptible Power Supply (UPS) for de-centralized operation in a distributed UPS system is described. The UPS system includes a number of UPS units that do not have communication links between them and therefore operate in a de-centralized manner. Coordinated operation in the UPS system is achieved through a controller associated with each UPS unit. The controller identifies when the operating power signal frequency on the UPS system does not correspond to a nominal operating frequency. In response to this condition, the controller generates a frequency reference signal that is used to control the inverter of the UPS unit. The controller continuously estimates the fractional loading of the distributed system by gauging the system response to disturbances, and sets its own operating point accordingly. The controller also ensures that the system operates at its nominal frequency independent of loading.

Abstract: An integrated varactor and piezoelectric device for an acoustic ink jet ejector includes a substrate having a first surface, the silicon substrate forming a first electrode, an epitaxial layer formed over the first surface of the silicon substrate, a silicon dioxide layer formed over the epitaxial layer, a second electrode formed over the silicon dioxide, a piezoelectric layer formed over the second electrode, a third electrode formed over the piezoelectric layer and an acoustic lens formed over a second surface of the silicon substrate. The acoustic lens is aligned with the center of the piezoelectric layer generally along an axis perpendicular to the first and second surfaces of the silicon substrate.

Abstract: Symbol recovery for multi-level digital signals has traditionally been difficult because of the nature of the eye pattern output by the discriminator (103), and especially its response to a noisy or impeded signal environment. This method and apparatus for recovery thresholds adjusts (411 and 417) to the current state of the discriminator (103) output of the received signal, based on an attenuated (301) version of that signal. Using a fast adjust mode and slow adjust mode, the threshold generating circuitry (331 and 361) adapts to the signal based on data from the received signal fed into lock detectors (329 and 359) which determine the mode to use.

Abstract: An uninterruptible power supply for supplying a load with AC output power generates the AC output power from an AC input source when the AC input source is within settable voltage limits and transfers to generating the AC output power from an auxiliary source of DC power when the AC input source is outside the voltage limits. A microprocessor provides monitoring and sampling of the AC input voltage to determine its amplitude and frequency, and uses this information to set the magnitude and frequency of the AC output voltage by generating a sine reference signal to control the AC output frequency and voltage phase angle. The microprocessor maintains a voltage phase relationship between the AC input power and AC output power to eliminate voltage and current transients at transfer times between the AC and DC input sources that would be present if the AC output suddenly had a drastic, voltage phase angle change.

Abstract: A ground power unit capable of no-break power transfer includes a rectifier for converting power from commercial mains to direct current, a switching circuit, a power transformer, and a pattern generator for controlling the operation of the switching circuit. Voltage and current sensors monitor whether the phase of the ground power unit is leading or lagging the phase of the aircraft power bus at the tinge of power transfer. The frequency and phase of the pattern generator converter is adjusted to bring the two systems into alignment quickly, well before the power transfer operation is completed. The ground power unit limits the power transfer between the two systems to prevent the overloading of either.

Abstract: A programmable power supply having a plurality of channels wherein each channel is adapted to output a selectable DC voltage, AC voltage, DC current or AC current. Each channel is adapted to select a DC reference signal or an AC reference signal and to scale the selected DC reference or the AC reference to output the selected signal. The outputted selected signals are monitored to provide a monitored channel signal indicating the value of the selected signal. The programmable power supply outputs monitored channel signals for each of the channels in a human perceivable format such as a display or printed format. At least some of the channels are adapted to be connectable to a temperature probe which outputs temperature signals and, in this embodiment, the temperature signals are monitored to provide monitored channel temperature signals, the monitored channel temperature signals being outputted in a human perceivable format such as a display or printed format or both.

Abstract: A linear feedback shift register comprises a shift register formed of first to (n)th flipflops cascaded in such a manner that an output of a (i)th flipflop is connected to an input of a (i+1)th flipflop, where 2.ltoreq.n and 1.ltoreq.i.ltoreq.(n-1). First to (n)th output terminals are connected to outputs of the first to (n)th flipflops, respectively, and a clock terminal connected to a clock input of each of the flipflops. First to (n-1)th multiplexors of a "1-out-of-2" type are connected at their first input to a common preset value input terminal. Second inputs of the first to (n-1)th multiplexors are connected to the outputs of the first to (n-1)th flipflops, respectively. Each of the first to (n-1)th multiplexors has a control input connected to an individual control terminal.

Abstract: A power switching system for controlling the conductivity of a plurality of thyristors of the gate turn-off type (GTOs) which are connected in parallel between two power sources by gradually introducing a time compensation to force the times of turn-off of each of the thyristors toward matched values by determining the turn-off time during each conduction cycle and thereafter advancing or retarding the turn-off signal for the following conduction cycle to correct for the difference in turn-off times. A difference signal is generated between time of turn-off of an average current of the thyristors and the time of turn-off of an individual current in one of the thyristors from which a time advance or delay signal is added to the thyristor turn-off signal in response to the current flowing in a capacitor type integrator. This allows the turn-off times to reach a perfect match during periods in which the current is the same for several cycles.

Abstract: A drive motor for each loom is selectively connected to a given commercial frequency power source for high speed rotation at normal running of the loom and to a low frequency power unit for low speed rotation at inching operation, thereby assuring accurate inching operation with cheap cost on looms under mass drive condition.

Abstract: An emergency apparatus for elevator which converts a DC power into an AC power by an inverter device in an emergency state to feed the AC power to an AC traction motor and an AC motor for door-opening and closing which have different rated voltages so as to drive a cage of the elevator and to open and close a door of the cage comprises selectively feeding a power through said inverter device to either of said traction motor or said motor for door-opening and closing, in an emergency state.

Abstract: This application discloses circuits for use with arc discharge devices wherein a D.C. or A.C. high frequency, high voltage source is provided in conjunction with either a low frequency or D.C. voltage source. The high frequency, high voltage circuit is a low power circuit providing sufficient voltage to ionize the arc. If desired the low power circuit may also control the major arc power obtained from the low frequency or D.C. source which does not require a ballast. By virtue of this arrangement much smaller, lighter and lower cost circuits than conventional ballast circuits can be used.

Abstract: To prevent high-intensity-discharge (HID) lamps from extinguishing for prolonged periods due to a power interruption or an appreciable drop in line voltage, a rectifier-battery combination provides standby power for operating a high-frequency inverter. The output of the inverter connects to the HID lamps through impedance means which passes a greatly reduced high-frequency current as compared to the normal lamp operating current, in order to sustain the operation of the lamps at a very reduced power level. Upon restoration of the normal line voltage, the lamps again operate with normal power consumption. The same wiring can be used for both the normal lamp operating current and the high-frequency sustaining current or separate wiring systems can be used if desired. The high-frequency current can be supplied simultaneously with the normal operating current or the high-frequency current can be supplied only during periods of power interruption.