Abstract: A desaturation detector receives signals from a gate driver and circuitry that indicate whether a power semiconductor device is on and in desaturation. A logic circuit produces a signal as a function of the signals, from which a latch circuit produces an output signal. The signal has first and second values respectively in an as-designed condition, and in a short-circuit condition in which the power semiconductor device is on and in desaturation. The output signal has the first value, and transitioned and latched to the second value in response to a transition to the short-circuit condition, which causes the gate driver to switch the power semiconductor device off. And filter(s) reduce noise within the desaturation detector.

Abstract: A desaturation detector receives signals from a gate driver and circuitry that indicate whether a power semiconductor device is on and in desaturation. A logic circuit produces a signal as a function of the signals, from which a latch circuit produces an output signal. The signal has first and second values respectively in an as-designed condition, and in a short-circuit condition in which the power semiconductor device is on and in desaturation. The output signal has the first value, and transitioned and latched to the second value in response to a transition to the short-circuit condition, which causes the gate driver to switch the power semiconductor device off. And filter(s) reduce noise within the desaturation detector.

Abstract: An undulating mixing device for precise, controlled agitation of sensitive biological and chemical solutions provides a base and a platform connected by four flexible connectors, a spring loaded motor mount assembly pivotally attaching a motor to the base, a turntable rotatably attached to the base, a tilt assembly pivotally and rotationally attached to the turntable and rigidly affixed to the platform, and a motor shaft that engages a groove on the turntable for causing rotation thereof. The tilt assembly includes an adjustable collar which controls the tilt or yaw movement of the platform as the motor effects rotation of the turntable. A selectively adjustable speed control switch sets the desired rotational speed of the motor via a microprocessor. The device functions without modification on a plurality of selected voltages and frequencies for achieving the desired rotational speed.

Abstract: An undulating mixing device for precise, controlled agitation of sensitive biological and chemical solutions provides a base and a platform connected by four flexible connectors, a spring loaded motor mount assembly pivotally attaching a motor to the base, a turntable rotatably attached to the base, a tilt assembly pivotally and rotationally attached to the turntable and rigidly affixed to the platform, and a motor shaft that engages a groove on the turntable for causing rotation thereof. The tilt assembly includes an adjustable collar which controls the tilt or yaw movement of the platform as the motor effects rotation of the turntable. A selectively adjustable speed control switch sets the desired rotational speed of the motor via a microprocessor. The device functions without modification on a plurality of selected voltages and frequencies for achieving the desired rotational speed.

Abstract: A device and method for adapting a computer terminal for connection to at least one external device communicatively couples an adapter to the computer terminal and to the at least one external device. The computer terminal is configured to transmit data and commands to the adapter in a manner prescribed by the computer terminal for communication with external devices. The adapter is configured to detect computer terminal signals and transform selected patterns of the computer terminal signals into instructions and information having a predetermined format for operating the at least one external device. The data and commands transmitted from the computer terminal are interpreted and transformed into instructions and information in a predetermined format for operating the at least one external device.

Abstract: Process and apparatus for calibrating an electrical device such as a circuit breaker, motor controller or monitor is taught. A precision power supply device is interconnected by way of appropriate input channels to the device to be calibrated for supplying a precise accurate calibration variable as an input. A personal computer PC is interlinked by way of a communications network with the apparatus to be calibrated and is also interlinked with the precision supply device so that the personal computer PC has available the exact value of input variable utilized. Gain adjustment calibration is made by supplying the predetermined value of circuit variables, for instance 10 amperes or 120V to the input terminals of the device being calibrated. Upon command, the personal computer PC instructs the device being calibrated to deliver to the personal computer PC those values of input variable which the device being calibrated interprets as the input variable value.

Abstract: A microprocessor used in solid state products has multiple interrupts and a single read only memory (ROM) masked for two or more product programs. The logic state of an input pin is set to select the appropriate program. If there is an error in one program or it becomes obsolete, the microprocessor does not have to be scrapped, but can be used to execute the other (another) product program. Separate interrupt selection routines for each interrupt, addressed from a common interrupt vector table, direct program execution to an interrupt branch table for the product indicated by the input pin. The product branch table contains addresses for the interrupt service routines for the selected product. The product programs are first separately linked with the interrupt branch table for the corresponding product.

Abstract: Process and apparatus for calibrating an electrical device such as a circuit breaker, motor controller or monitor is taught. A precision power supply device is interconnected by way of appropriate input channels to the device to be calibrated for supplying a precise accurate calibration variable as an input. A personal computer is interlinked by way of a communications network with the apparatus to be calibrated and is also interlinked with the precision supply device so that the personal computer has available the exact value of input variable utilized.

Abstract: A motor protection relay is taught which determines effective and RMS values of current on a cycle-by-cycle basis by measuring three-phase currents at 10.degree. intervals in a line cycle and then determining the positive and negative sequence components thereof by storing the accumulated information in a memory. In order to increase the dynamic range of the sensing apparatus, only the negative half wave of each current is sensed and the positive half wave is reconstructed by finding the 180.degree. phase shifted equivalent thereof in the negative half wave.

Abstract: Motor protection relay is taught in which a microprocessor is utilized in conjunction with a reduced voltage motor starter and the electrical motor system which it operates upon to cause the motor to start in stages. The microprocessor-based system infers a start by the presence of a minimal amount of electrical current flowing in the three-phase system which supplies power to the motor starter and thence to the motor. After the start has been inferred, the microprocessor controlled protection device will issue a transition command for the second stage of the start operation where higher voltage is placed across the motor terminals when the in-rush current has fallen to a predetermined programmable value which approximates full load current, for example. An "incomplete sequence" feedback line is provided which is supplied from the auxiliary contacts of the low voltage starter to the microprocessor.

Abstract: A motor protection relay is taught in which the temperature of a rotating rotor is inferred from the current flowing in the lines which supplies the motor and from resistance temperature detection devices in the stator of the motor. By utilizing a periodic predictable established interrupt routine within the software which controls the microprocessor which in turn controls the monitoring device the time based model for inferring rotor temperature can be freed of a requirement to use a fixed sampling time rather the time for calculations can be variable. The total number of counts that particular interrupt routine has taken place will be factored into the calculations to make the calculations accurate. The thermal model is further improved by expressing it in terms of current squared times time so that the component portions of the equation which represents the thermal model can use accumulator inputs into which values of line current squared have been previously placed.