Abstract: A latching mechanism comprises a stationary chamber (1), a spring-loaded main slide (2) which is guided along the stationary chamber (1) in a first direction, a spring-loaded message slide (3) disposed inside the stationary chamber (1) which is guided in a second direction perpendicular to the first direction, and a spring-loaded snap lever (4) which is pivotally mounted inside the stationary chamber (11) and which supports the switch lock's toggle linkage during the switched-on position of an overload protection switch. The main slide (2) is mechanically coupled to a manual actuator. During switching-on, the main slide (2) is moved in the direction of the message slide (3), such that the message slide (3) is moved via interacting bevels (19, 28), and locks the main slide (2). During tripping, the trip latch moves the message slide (3), causing the main slide (2) to be locked into a tripped position and causing the snap lever (4) to be released.

Abstract: A multilayer circuit board or laminated circuit board includes an insulated mounting area for a surface mount package. The mounting area is provided in a recess or portion of the circuit board where the circuit board is only a single layer thick. The insulated mounting area is provided in a blind via in the multilayer circuit board. The insulating medium associated with the single layer provides a heat conductive yet highly electrically insulative mounting area for a heat sink. The heat sink may be mounted on a side opposite the electrical device. The heat sink may be a standard heat sink or a copper coil directly soldered to the circuit board. The heat sink mounting advantageously eliminates the need for bolts, nuts, brackets, and an additional insulating layer necessary to insulate power semiconductor components.

Abstract: A multiphase circuit interrupter includes a plurality of power phase sections for establishing and interrupting electrical power carrying paths for a plurality of phases. Each power phase section includes first and second conductive regions which contact one another to complete the current carrying path for the phase. The second conductive region is movable to an interrupted position to interrupt the path. An interphase current carrying path is established between the power phase sections to conduct electrical energy between the sections following a trip event in any one of the sections. The interphase current carrying path may be established by a conductive element extending between the power phase sections. Channels may be formed in the interrupter housing between the power phase sections to communicate conductive plasma generated during separation of the contact regions from one another between the power phase sections.

Abstract: A method and apparatus for selecting one of several different modulating signals for use with a system including a PWM controller and an inverter to generate low frequency alternating voltages on three motor supply lines, modulating signals selected as a function of a modulating index to minimize harmonic distortion in the alternating voltages, minimize switching losses, maximize overall system gain at high modulating index values and maximize the linear range of system operation.

Abstract: A motor is reconnected to a motor drive by exciting the motor to induce a back EMF, determining a speed of rotation of the motor based on the induced back EMF induced, and reconnecting the motor drive to the motor based on the speed determined. In order to induce the back EMF, current which flows through the motor is controlled using first and second regulators. The outputs of the first and second current regulators are separated from each other in phase by approximately 90.degree.. A positive feedback loop is established by using the output of one of the first and second regulators to generate an input for the other one of the first and second regulators. The positive feedback loop advantageously causes the back EMF to continually increase as the motor continues to be excited, or at least not decay so rapidly that the speed of the motor cannot be accurately determined.

Abstract: An integrated RISC and relay ladder logic processor uses shared registers, program counter, bus lines, and processing circuitry to eliminate delays associated with transfer of control in co-processor type architecture. The RISC instructions do not significantly interfere with the specialized hardware needed for rapid relay logic execution, the latter which may be further improved through the use of a pipeline well suited for relay ladder logic which creates few pipeline hazards. Two levels of condition codes are used for the arithmetic and logic instructions to permit nested arithmetic operations without interference with those instructions visible to the user. Hybrid instructions are provided to synchronize the relay ladder instructions with the arithmetic instructions, thus truly integrating the two instruction sets.

Abstract: A method and apparatus for starting a motor drive into a rotating motor, the method including determining an initial search frequency and search current wherein the current is less than a rated drive current, providing a d-axis flux generating current to the motor at the search frequency and at a magnitude equal to the search current, monitoring a q-axis flux error, decreasing the search frequency until the d-axis flux error is less than a threshold value, thereafter increasing the search current to the rated drive current and, after a flux-up period, providing both q-axis torque producing current and d-axis flux producing current to the motor.

Abstract: A method for retaining a movable contact in a circuit interrupter is applicable to interrupters including first and second contacts, at least one of the contacts being movable. A movable element supporting the movable contact is displaceable between a conducting position wherein the movable contact abuts a cooperating contact to complete a current carrying path through the device, and a non-conducting position wherein the movable contact is electrically separated from the cooperating contact. In accordance with the method, the movable contact is displaced by an interrupt initiation device, and a carrier or retainer is displaced by gas pressure resulting from arcs generated by movement of the contact. The carrier is guided in its displacement within the device housing from a normal operating position to a retaining position. The carrier includes an abutment element that physically contacts the movable element to prevent it from rebounding into contact with the cooperating contact.

Abstract: A method and apparatus for determining the critical dwell time required between firing pulses generated by a PWM inverter to eliminate greater than twice overvoltage on motor supply lines. Critical dwell time is correlated with line parameters including inductance and resistance per unit length and is then provided to a controller to alter voltages provided to a motor to eliminate overvoltage.

Abstract: A multi-tasking operating system for real-time control of industrial processes integrates ladder type programs and state-type programs by viewing each as a series of instructions with an implicit pointer list pointing to the next instruction. A fixed number of instructions of each program task are executed after which the effective pointer to the next instruction is stored toward the next time that task is invoked. Multiple tasks that need to be coordinated can be linked with subtasks that can be guaranteed complete execution by allocating sufficient instructions to those subtasks.

Abstract: A redundant controller employs two controller chassis having replaceable functional modules interconnected electrically within the chassis. System back up modules in the chassis coordinate the switching of control from a primary to a secondary chassis according to chassis redundancy state information of the chassis stored in the backup modules and module redundancy state information stored in the modules unique to the modules.

Abstract: An apparatus for receiving and modifying a PWM trigger signal such that consecutive ON and OFF periods have durations at least as long as a critical dwell time where the critical dwell time is the minimum time required to avoid greater than twice overvoltage. The trigger signals are modified by, each time a trigger signal changes from low to high, providing a minimum pulse signal which remains high for the greater of a critical dwell time or the time over which the trigger signal remains high, when the minimum pulse signal changes from high to low, providing a maximum pulse signal which remains low for a critical dwell time, adding the maximum and minimum pulse times using a logical AND gate and providing the output of the AND gate as a modified trigger signal.

Abstract: An apparatus for essentially eliminating transmission line reflected waves and standing waves and for reducing common mode transient currents for use with a three phase motor controller, the apparatus including a common mode choke in series with a filter network between an inverter and a motor, the filter including three inductors and three resistors, the inductors and resistors together forming three inductor-resistor pairs, each pair including an inductor in parallel with a resistor, each pair linked to a separate one of three transmission supply lines which link the inverter to the motor, values of the resistors and inductors selected according to transmission line theory.

Abstract: A programmable controller reduces the power used by the relays. The controller design permits energization of relay coils without subsequent maintenance of the relatively high voltage required for energization. The design permits the voltage across the relay to be lowered to an activated relay coil maintenance level with a design that minimizes the space required for the relay circuitry.

Abstract: A circuit card of an industrial controller may be removed or inserted under power without loss of memory or disturbance to the power supplies of other modules through the use of a power failure signal derived from shortened pins on the connector between the card and the industrial controller. The power failure signal activates a timer delaying connection of the board components to power until the physical connection between the card and the industrial controller has stabilized. At this time current drain is ramped up by a controlling series FET. Upon removal of the card, the power failure signal causes outputs of an on-board microprocessor to be pulled to particular states necessary to prevent disturbance of a battery backed-up RAM and to eliminate current flow through protection diodes on other memory type devices attached to the microprocessor.

Abstract: A method and apparatus for minimizing motor instability under no load conditions, the method including identifying instability by comparing consecutive current half cycle periods and, where the difference between half cycle periods is sufficiently large, determining that instability exists and modifying controller modulating waveforms by reducing waveform magnitude until stability is achieved. Preferably the apparatus for achieving stability includes only a single current zero crossing sensor to minimize hardware costs.

Abstract: A bidirectional lateral insulated gate bipolar transistor (IGBT) includes two gate electrodes. The IGBT can conduct current in two directions. The IGBT relies on a double RESURF structure to provide high voltage blocking in both directions. The IGBT is symmetrical, having an N-type drift region in contact with an oxide layer. A P-type region is provided above the N-type drift region, having a portion more heavily doped with P-type dopants. The double RESURF structure can be provided by a buried oxide layer, a floating doped region, or a horizontal PN junction. The IGBT can be utilized in various power operations, including a matrix switch or a voltage source converter.

Abstract: A loosening-resistant threaded fastener system and method of use includes a washer that is axially movable on a threaded stud, a threaded nut having threads which cooperate with the threaded stud, and a washer anti-rotation mechanism to prevent the washer from rotating on the stud about a fastening axis. One of the washer and the nut may include a plurality of protrusions while the other of the washer and the nut has a plurality of detents. The protrusions and the detents engage one another at a plurality of angular positions. Rotating the nut on the stud while in contact with the washer results in distinct, audible clicks which may be counted to obtain a pre-determined tightness.

Abstract: Inter-operability of products connected together to form an industrial control system is determined by defining each product as a set of services describing points of interface between the products and by determining complementary services necessary for inter-operability from a table listing complementary services. A new product may be evaluated for inter-operability by comparing its services to services of products with which inter-operability is desired. In one mode of operation after definition of the products in which inter-operability is desired, a necessary list of services is compiled from a database and translated by a relationship map to complementary services which define a virtual product having the desired inter-operability. Inter-operability of an entire control system may be thus modeled prior to construction.

Abstract: An industrial controller provides a primary controller and a redundant secondary controller and allows switchover between the controllers in the event of a failure in the primary controller. The process of qualification of the secondary controller in which its programming is made to match the primary controller may be inhibited to permit the secondary controller to maintain a clean version of an upgraded program executing on the primary controller. The clean program may be reverted to in the event an upgrading of the program in the primary controller is unsuccessful. Switchover is permitted even though the qualification of the secondary controller is not enabled.