Abstract: Circuit apparatus for providing a signal indicative of speed and direction of rotation of a d-c machine is provided which utilizes an a-c tachometer output as the speed signal from the bi-directional d-c machine. The circuit apparatus includes means responsive to the armature terminal voltage and armature current to provide a signal proportional to the counter electromotive force generated in the armature. Polarity circuit means responsive to nulls in the armature current and the signal proportional to the counter electromotive force generates a signal which is a function of the polarity of the counter electromotive force. An absolute value circuit means is provided for receiving the output of an a-c tachometer driven by the d-c machine.

Abstract: A speed regulator and control system for controlling a motor from a polyphase AC source includes a data processor and a regulator and rectifier control interfacing the data processor with a controllable rectifier driving the motor is disclosed. The regulator and rectifier control, under control of the data processor, selectively transfers system parameters to the data processor, receives a calculated value proportional to firing angle from the data processor and supplies firing pulses to the rectifier to selectively connect each phase of the AC source to the motor as calculated by the data processor.

Abstract: A control circuit for a direct current motor having separately excited armature and field windings and operable in both the constant torque and constant horsepower modes includes a speed control circuit having a transfer characteristic providing an extremely high gain at lower frequencies and a low gain, for example unity, at higher frequencies and further includes means to reduce the low frequency gain when motor operation is switched from the constant torque to the constant horsepower mode.

Abstract: A circuit for generating a signal proportional to the average current of an inductive load supplied from a supply of intermittent electrical power and having a free-wheeling path through which load current flows during periods in which the load is not connected to the power supply, includes means to provide a first signal which is a function of the current in the free-wheeling path and second means to provide a second signal which is a function of the supply-load current. By appropriately combining the two signals an output proportional to the average load current is obtained. The output signal can be utilized for control functions such as controlling the operation of switching devices which, in turn, control the application of electrical power to a d.c. motor.

Abstract: An apparatus for determining the temperature of railroad car wheel journals (i.e., "hotbox" detector) includes a sensor including a pyroelectric cell responsive to infrared radiation signals, which are focused onto the cell, to output voltage signals as a function of the radiation signals inputted thereto. The sensor exhibits a nonlinear gain response to different frequencies of input signals and compensation is provided by coupling the output of the sensor to a differentiating circuit which has a similar but relatively negative gain response. The output of the differentiating circuit is a substantial voltage replica of the infrared input signal and this voltage signal may be applied to a suitable utilization device such as one which records journal temperature and/or provides a suitable alarm when a sensed journal temperature exceeds a predetermined value.

Abstract: In a continuous hot strip mill comprising a roughing mill, a finishing mill and an intermediate delay table including a coiler, a method and apparatus are provided for determining the temperature of a hot metal bar entering the finishing mill based upon the temperature of the bar leaving the roughing mill. Taken into account are the times spent on the open portion of the delay table and in the coiler and the differences in heat loss by the bar in these two conditions.

Abstract: A circuit for the generation or development of a gating signal for a semiconductor device which is isolated from the circuit of the device itself is comprised of a pulse generating section which feeds pulses to the primary winding of a transformer to thereby induce pulses into the transformer secondary winding. An output section is connected to the secondary winding of the transformer which provides alternately, relatively positive and negative going output signals which serve as the gating signals for the semiconductor device.

Abstract: A circuit for monitoring semiconductor junction temperature includes means for obtaining a signal representing the current flowing through the semiconductor, a current controller, an electrical analog of the thermal system of the semiconductor, a direct current supply, and a voltage level detector. The current controller is connected in circuit with the analog and the combination to the d.c. supply. The current conducted by the controller via the analog is controlled by the signal such that the voltage across the analog indicates junction temperature and this voltage is monitored by means of the level detector.

Abstract: A circuit for shifting the phase of an input voltage provides an output voltage of the same magnitude but of a phase differing from that of the input voltage by a variable amount in accordance with a selectively variable control input.

Abstract: A shorting clip, for use with a semiconductor package, for shorting the several package leads comprises a conductive member having leg portions to electrically contact each of the leads of the package. Retaining means cooperating with resilient means operative to bias the package and clip apart serve to maintain the clip-package assembly in positive registration.

Abstract: Ramp signals having rounded starts and finishes are provided through the method of producing an electrical voltage signal comprised of approximately circular portions and approximately straight line portions wherein the straight line portions are approximately tangential to the circular portions. In achieving the desired ramp signals, suitable circuitry is provided in which, in one embodiment, a high gain amplifier is selectively fed a step input voltage to initiate the ramp signal. The amplifier has a voltage limited output and is series connected to a first integrator. The first integrator has a voltage limited output and is series connected to a second integrator which produces the required ramp signal. The circuit also contains two feedback loops. The output from the first integrator is fed to the input of the high gain amplifier via an inverting amplifier. The output of the second integrator is fed to the high gain amplifier via a resistor.

Abstract: A motor control system of the type employing phase controlled rectifiers for controlling the power supplied from a polyphase alternating current source to a direct current motor includes circuitry to detect the existence of a rectifier which is conducting at an improper time and to provide appropriate corrective action to terminate such improper conduction.

Abstract: A power supply system includes a plurality of power supplies having their outputs connected in parallel to provide a common voltage to an electrical load. Each power supply is self-regulating and capable of automatically turning off under power supply malfunction and overload conditions and turning back on after the condition is removed without affecting the operation of the other power supplies or interrupting the common voltage.

Abstract: A power regulating system controlling a flywheel-type load peak shaver is described wherein average power to a cyclic load is continuously subtracted from instantaneous load power to provide a command signal proportional to the required load peak shaver power flow. To this command signal is compared a feedback signal proportional to the power being supplied by the load peak shaver. The difference between the command and feedback signals controls the firing angle of a cycloconverter supplying power to the slip rings of the wound-rotor load peak shaver.

Abstract: An electronic filter circuit comprised of summing circuits and integrating circuits is interconnected such that the filter may use the same components to serve either as a band-reject or a band-pass filter having the same natural frequency. Changing of the filter operation between the two modes is accomplished simply by the interchange of two component values.

Abstract: A current sensor provides a voltage signal which is proportional to the average current flowing through a semiconductor device junction. This voltage signal is applied to a first analogue circuit which produces an output voltage indicative of the average power dissipated at the junction. The output of the first analogue circuit is applied to a second analogue circuit which outputs a voltage signal indicative of the temperature difference between the junction and a heat sink associated with the semiconductor device and to a third analogue circuit which outputs a voltage signal indicative of the temperature difference between the heat sink and ambient. The ambient temperature is sensed by an ambient temperature sensor which outputs a voltage signal indicative of the ambient temperature. A voltage summing circuit sums the output voltages from the second and third analogue circuits and from the ambient temperature sensor, and produces an output voltage indicative of the junction temperature.

Abstract: A power supply system includes a plurality of power supplies having their outputs connected in parallel to provide a common voltage to an electrical load. Each power supply is self-regulating and capable of automatically turning off under power supply malfunction and overload conditions and turning back on after the condition is removed without affecting the operation of the other power supplies or interrupting the common voltage.

Abstract: In a power system, control signals derived from a measurement of dynamoelectric machine output voltage and current are selectively applied to an exciter to control the current in a field winding of the machine to control the machine reactive volt-amperes and output voltage.

Abstract: A power supply system includes a plurality of power supplies having their outputs connected in parallel to provide a common voltage to an electrical load. Each power supply is self-regulating and capable of automatically turning off under power supply malfunction and overload conditions and turning back on after the condition is removed without affecting the operation of the other power supplies or interrupting the common voltage.

Abstract: In a turbine powered generating system the rate of fuel flow for auxiliary firing of a steam turbine is automatically controlled to control the generation of steam for the turbine in accordance with turbine operating parameters and system power demands. Fuel flow rates are controlled within program selected limits to minimize stresses on the steam turbine, thus increasing the performance and life expectancy of the turbine.