Abstract: A compressor coupled to a load of smaller capacity is provided for loading with a setpoint adjusting circuit substituting a pseudo-setpoint signal for the pressure signal derived from the load, so that the master-controller operates in response to a signal increasing gradually from a low initial value until matching in magnitude with the assigned setpoint signal for normal operation. The master-controller is modified so as to bypass the normal modulation means during loading, a minimum inlet valve opening being imposed initially and concurrently the bypass valve being allowed to close under the low initial value, inlet valve control being enabled after the bypass valve has closed and in accordance with said gradual increase of the pseudo-setpoint signal. After load pressure has reached the assigned pressure setpoint in magnitude, the master-controller normal operation is reinstated.

Abstract: In a compressor control system, a subcontroller is coupled with the master-controller in order to detect, when the bypass valve is being modulated, whether there is a deviation between the minimum inlet valve position assigned to the system and the actual inlet valve position. In such case, correction of the inlet valve position is automatically effected by the subcontroller in either direction to restore the minimum assigned inlet valve position.

Abstract: A walking beam for interlocking control devices such as circuit breakers is characterized by a central bracket for supporting, on a mounting plate of the control devices, the beam through its central pin, and a single screw is provided for adjusting the central pin level within the bracket until the plungers at the two ends of the beam are fully engaged with their respective control members, which could be the crossbars of a circuit breaker. Once the walking beam has been properly adjusted, the central pin and the screw are fixed in position with nuts.

Abstract: In a compressor control system, surge upon a sharp demand for lower airflow is avoided by placing an offset value above the minimum airflow absolute limit. When reaching downward under inlet valve modulation such offset limit, the master-controller initiates bypass valve modulation and a subcontroller brings the inlet valve from the offset limit down to the absolute minimum airflow position. Provision is made against exceeding the offset limits during such excessive demand downward by imposing a limit to the inlet valve position command. Upon a return upward toward normal operation, provision is made against an intervening and sudden downward demand by imposing a limit to the inlet valve position command representing the minimum airflow operation.

Abstract: In a computer-based motor drive, a microcomputer is responsive to a plurality of input signals drived from the motor AC lines whenever contacts, or pushbuttons, commanding specific control operations to be performed, are closed. In such case, opto-couplers convert such AC voltage into a square pulse train which conveys a succession of digital high and low levels. A reference signal is derived, through an opto-coupler form the AC line, which in its high and low logic form is delayed in relation to the input signal trains. By sampling the input signal upon the occurrence fo a falling edge of the reference signal, then at least after the delay existing between the signals, the validity of the input signal is tested by comparing the two successive samples, thereby insuring a true command addressed to the microcomputer.

Abstract: A clip-connected terminal conductor uses a terminal lug for tightening together with a screw the line cable and the conductor end. A channel is provided in the lug for inserting therein, and guided by lateral wall of the channel, a spring-like member having centrally a boss which engages the aperture of the conductor end. The spring-like member has opposite ledges for clipping with the front and the rear edge of the base of the lug and channel.

Abstract: A control processor in a robotic system treats optically sensed locations along the path ahead of the tool, which are classified in relation to elapsed distances and identified in 3-D coordinates and 3-axes tool orientation, to apply in real time and under feedforward a control signal representing the error between anticipated tool position and anticipated sensed location on the path. In the process, the anticipated sensed location is obtained by reference to a model made ahead of time with the stored sensed locations grouped as a function of elapsed distances and having a common algebraic feature, such as the slope or the change of slope. A taught path for the robot has been recovered by the control processor also based on elapsed distances and control is related to actual tool position provided by the robot.

Abstract: An induction motor torque/flux control system the motor flux is forced down while accelerating and force up while decelerating to maintain a required flux level at all speeds. This is achieved through vector control by generating a direct current component in relation to the flux demand while imposing limits thereto corresponding to the maximum desirable resultant current vector, and by generating a quadrature current component which is held between limits defined by the sum of the squares of the two current components. The three-phase currents of the motor generated by vector control transformation are used to control a voltage-source inverter in a bang-bang fashion. The conventional bang-bang technique is improved by typing up one pole while controlling in the bang-bang mode the two other poles. To this effect the motor back emf is detected when the poles are simultaneously tied to one of the DC link terminals, and the tied-up pole is selected by the emf so detected.

Abstract: A circuit breaker combines DC and AC arc extinguishing capabilities by associating a magnet applied permanently upon the outside wall of the insulating housing of the breaker and a U-shaped member of ferromagnetic material lodged and held inside the housing, both being in line with the centrally disposed arc chamber and the fixed and stationary contacts thereof.

Abstract: A control processor in a robotic system treats optically sensed locations along the seam path ahead of the tool, which are classified in relation to elapsed distances and identified in 3-D coordinates and 3-axes tool orientation, to apply in real time and under feedforward a control signal representing the error between anticipated tool position and anticipated sensed location on the path. In the process, the anticipated sensed location is obtained by interpolation between actually sensed locations. A taught path is recovered from the robot. The control processor operation is also based on elapsed distances and related to actual tool position provided by the robot.

Abstract: In a compressor system, surge detection is provided by sensing the current of the motor driving the compressor and reading oscillations of the current about the average thereof and above and below two opposite threshold levels from such average current and counting the polarity changes within a time interval containing so many samples of the current and defining a sliding window.

Abstract: In a direct AC/AC converter, fault protection is performed with a minimal number of fault detecting devices and the rating of such fault detecting devices is reduced while still being able to respond quickly to a fault current. This is achieved by using a current sensor in common to at least all the current lines of one group of switches and by combining the operation of such common current sensor with the operation of one current sensor associated with the related output phase line. In another embodiment, all the current lines connected to a switch, for all the groups of switches, are passed through a common and single current sensor.

Abstract: In a multiphase AC/DC converter system a single transformer is used having phase shifted tappings drawn from a polygonal succession of long and short windings wherein some of the windings carry only the difference between the outputted currents derived from the tappings.

Abstract: A current source inverter for a load commutated induction motor drive is controlled in relation to the direct and quadrature components of the current vector as assigned in response to stator voltage, speed reference and actual speed. Control is on the inverter and the converter in relation to both components.

Abstract: An installation for the dynamic burn-in testing of a plurality of digital circuits, and/or microcomputer-controlled circuits, mounted in a burn-in chamber for testing includes a personal computer; power supply for the digital circuits, and a bilateral line of communication between the PC computer and each of the digital circuits; the PC computer interrogating separately, and at will, any of the digital circuits as to their status and capability of changing status while retrieving any indication of a critical testing condition from any digital circuit, to determine a failure-free burn-in time.

Abstract: Adaptive control is used in an asynchronous motor drive. A reference model based on the model equation of the motor is combined with an adjustable model responsive to the direct and quadrature components of the current and to an estimated speed. An adaptive mechanism counting in a P-I amplifier expands to the direct deviation between the direct and quadrature components of the flux outputed by the two models and generates a feedback signal representing the estimated speed. The adjustable model reacts to such feedback signal so that the estimated speed readily becomes the actual speed of the motor. As a result, a tacho-less AC motor drive is obtained in which under any running conditions the motor immediately takes the required speed.

Abstract: An image processing system uses the digital expression of the video image of a light stripe derived optically from a seam to create a 1-D signal representative of a one-pixel wide line. The target coordinates for the tool operating on the seam is converted directly into 3-D tool position and orientation from the 1-D signal. Matching with models is effected in real time by comparing symbolic attributes of the graphs built up with the 1-D signal and with standard seams. From such matching is selected the operative corner, or target for the tool.

Abstract: In a load commutated inverter induction motor drive a parallel capacitor bank is used in part to force-commutate the thyristors of the inverter as triggered by auxiliary thyristors and turned off by the other part of the capacitor bank.

Abstract: A look-ahead sensor attached to the its effector end deviates upon each control action upon the robot toward a new position along the seam path. The chord across the seam path from the present effector end to the contemporaneously sensed seam path location is determined and used with the present orientation of the effector end to determine an additional yaw angle compensating for the deviation. As a result, the look-ahead sensor is constantly brought back on track.

Abstract: In a load commutated induction motor drive stability is achieved in a runaway situation by generating in response to the motor speed reference signal a signal representative of the desired power factor angle and in using such signal to delay by that much the gating pulses controlling the current-sourced inverter.