Abstract: A method and apparatus for eliminating greater than twice over voltage by altering firing signals provided to a PWM inverter. The signals are altered by either limiting their maximum and minimum on-times or eliminating signal changes in a symmetrical fashion so that the overall fundamental component and magnitude of a resulting low frequency alternating voltage is substantially unaltered.

Abstract: A hydrodynamic sleeve bearing for supporting the shaft of a relatively large electromechanical machine. The bearing includes a base element and a cap element matable about the shaft to produce the bearing housing. The bearing housing when assembled includes a shaft receiving portion through which the shaft extends and a sump portion for containing a lubricant fluid. The design of the present invention minimizes the axial length of the shaft receiving portion to approximately that of the bearing liner contained therein. As a result, the weight of the cap element will be significantly reduced over many prior art constructions. Respective lubricant seals are attached at opposite end faces of the shaft receiving portion. The lubricant seals and the end faces are configured to permit lubricant fluid to flow directly back into the sump. The lubricant seals may be installed in a plurality of angular orientations, which may be particularly useful if a selected sensor device is installed thereon.

Abstract: A method and apparatus for testing a digital integrated circuit (IC) for faults wherein the IC includes a memory, a microprocessor, an operand register, and a random data generator which is responsive to integrated circuit data indicative of the instantaneous IC state. A short test code including operational code instructions in the memory is performed by the microprocessor which manipulates data in the operand register. Periodically, the random data generator provides seed data to the microprocessor which changes the test code in a random manner and modifies the data stored in the operand register. At the end of a prescribed number of passes through the test code, the data generator produces an IC signature which can be compared to a known correct signature to identify IC faults.

Abstract: A shaft-carried speed reducer is provided having an adaptable mounting arrangement. The hub of the speed reducer is configured having a substantially cylindrical axial bore. At least one annular groove may be defined in the axial bore to receive a snap ring when desired. A removable adapter having a tapered interior surface may then be situated in the hub bore to abut the snap ring. As an alternative to such a snap ring, an annular flange may be provided on the removable adapter to engage an end face of the hub. A tapered sleeve member engages the tapered interior surface defined on the removable adapter to effect securement of the hub to the shaft. If a single adapter is used, it may be inserted from either side of the hub in some configurations. Further, some configurations permit a pair of adapters and corresponding sleeve members to be used. The adapter and snap ring, if any, may be removed when the hub is to be secured to a screw conveyor drive shaft or the like.

Abstract: A method of providing a standard coordinated time throughout spatially separated functional modules of an industrial controller employs a module operating as a time master which transmits a coordinated time to various dependent modules through communication modules. The dependent modules have local clocks which are synchronized to the coordinated time value by adjusting their clock frequency according to the difference between local time provided by that clock and the coordinated time value. This gradual correction prevents lost count values and disruption to the control process. The most and least significant bits of the time value may be transmitted at separate rates to reduce link traffic.

Abstract: The present invention is directed to a flexible coupling device adapted to connect a first rotatable shaft with a second rotatable shaft. The coupling device generally includes a pair of opposing hubs, each of which is adapted to be secured to a respective shaft. A connecting sleeve made from an elastomeric material extends between and engages each of the hubs. According to the present invention, the connecting sleeve also contains a rigid member defining at least one failsafe element or rigid engaging element that prevents the hubs from disengaging the connecting sleeve should the elastomeric material begin to wear and fail.

Abstract: An apparatus reducing capacitive coupling between the stator and the rotor of an electromagnetic machine. The apparatus includes an electrically connective shield positionable between the stator and the rotor, the shield electrically separated from both the stator windings and the rotor when so positioned. A grounder electrically connects the shielder to ground thus substantially reducing capacitive coupling between the stator and the rotor.

Abstract: The present invention provides for electronic braking of DC brushless motors by developing a feedback signal based on the back EMF of the motor. This feedback signal is used to provide a signal to the motor permitting current flow from the motor into the controller of a controlled level to slow the motor down. Reliance on the back EMF of the motor eliminates the need for a commutation signal when an emergency stop is required.

Abstract: A method and apparatus to be used with the motor controller for reducing phase shift between the feedback signal and the correction signal. Wherein the feedback signal is compared by the controller to a reference signal to provide the correction signal used to alter motor control signals. The method includes changing a correction signal according to a transfer function to produce a filter signal wherein the transfer function includes two variables: k.sub.n and .omega..sub.n, .omega..sub.n always being greater than zero, and k.sub.n being negative when the feedback signal is phased shifted into a medium frequency range. The method and apparatus produce filtered signals that are phase shifted and amounts determined by the k.sub.n and .omega..sub.n variables. Where k.sub.n is negative, the filtered signal is phase lagged by an extreme degree.

Abstract: A method and/or apparatus for altering command voltages when a modulation index is greater than unity in order to maintain the linear relationship between the fundamental component of phase voltage and the command voltage in PWM inverter or converter usage. The method and/or apparatus calculates and provides an in phase waveform to be added to the command voltage prior to comparison of the command voltage to a carrier signal, the sum of the waveform and command voltage producing a modified command voltage which maintains said linear relationship.

Abstract: A reset circuit for an overload relay includes a timing circuit coupled to a switching circuit for automatically resetting the relay a predetermined time after a trip. The timing circuit includes a capacitor and a resistor in parallel with a reset coil. The capacitor is charged during normal operation and begins to discharge through the resistor following a trip at a first rate determined by the size of the resistor. The switching circuit includes a pair of transistors, a pair of capacitors and a pair of resistors. When the capacitor in the timing circuit has discharged a predetermined amount following a trip, the switching circuit is triggered and couples the capacitor to ground through one of the transistors, causing a rush of current through the reset coil sufficient to reset the relay.

Abstract: A magnetic top stick for use at the opening portion of a core slot of an electromagnetic device includes a group of magnetically anisotropic members arranged in a substantially non-magnetic body adapted to fit snugly within the core slot. The magnetic properties of the group of members combine to provide the top stick with an overall high magnetic permeability in the depth direction of the core slot and overall low magnetic permeabilities in the width and longitudinal directions of the core slot. A convenient method of manufacturing the top stick includes first forming magnetically anisotropic sheets by cold rolling and annealing, then laminating and heat processing the sheets with B stage materials to generate a unitary laminated structure. The unitary laminated structure is sectioned into multiple magnetic flux bars which are in turn disposed in the non-magnetic body forming the top stick.

Abstract: A multilayer circuit board system or laminated circuit board system for use in a motor controller includes a motherboard, at least one power substrate circuit board, and a capacitor circuit board. The power substrate module includes a mounting area provided in a recess, window or portion of the circuit board where the circuit board is only a single layer thick. The single circuit board layer at the mounting area provides a heat conductive yet highly electrically insulated mounting area for receiving a heat sink. The heat sink can be mounted on a side opposite the electrical device. The capacitor circuit board, power substrate circuit board, and mother circuit board are interconnected without the use of external connectors or wires. A flexible circuit board layer or SCM.TM. interconnect interface allows the circuit boards to be connected solely by printed circuit (PC) wires.

Abstract: A solder resist pattern for a single in-line package (SIP) finger connector, or other interface member includes small solder resist features spaced closely together. The features can be circular, square, diamond-shaped, star-shaped, or other geometry and preferably are placed on finger connectors in a photo-imaging process. The pattern includes meniscus channels which are narrow enough to prevent solder from adhering to the finger connectors. The surface area of the features is small enough so that the pattern can be easily removed by a low impact or non-contact operation. Preferably, the pattern is removed by a hot air solder knife after the board is subjected to a solder wave.

Abstract: A multilayer circuit board or laminated circuit board for use in a motor controller is described. The multilayer circuit board is preferably utilized as a power substrate module. The power substrate module includes a mounting area provided in a recess, window 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 single circuit board layer at the mounting area provides a heat conductive yet highly electrically insulated mounting area for receiving a heat sink. The heat sink can be mounted on a side opposite the electrical device. The heat sink may be standard heat sink or a copper coil directly soldered to the circuit board. The multilayer circuit board includes an enhanced conductive layer for receiving the surface mount device. The enhanced conductive layer preferably includes an insulative frame which holds copper slugs.

Abstract: A method and apparatus to be used with a motor controller for determining RMS line current during a start-up period or a stalled period using electrical values known to the controller. Various equations relate RMS line current to monitored thyristor and source voltages as well as the duration of non-conducting periods in line voltages to determine the RMS line current.

Abstract: A "figure 8" shaped saturable reactor including a central leg, two lateral legs, an upper bar connecting the upper ends of each leg, a lower bar connecting the lower ends of each leg, and a coil wrapped around the central leg, the cross-sectional area of the central leg at its narrowest point being less than the cross-sectional areas of the two lateral legs combined so that the central leg saturates prior to the lateral legs saturating.

Abstract: A multitasking industrial controller for real-time control of machinery and the like permits the use of both periodic and event driven tasks by establishing a hierarchy of both task types in the form of priorities that resolve conflicts between events of the same and different types. The unpredictability of the event driven tasks on scheduling of tasks is addressed by watchdog time values assigned to each task which confirm timely execution of the task in practice despite the risk of preemption by other tasks. Flexible software definition of event driven tasks is made possible by delegating the detection of the events to input/output modules executing independently of the processor executing the operating system.

Abstract: A dual channel communications method including: (A) providing a control system with a central control station and a remote sensor for sensing a process status, the central control station and the remote sensor being connected by a power supply line and an output line; (B) impressing a non-periodic high-amplitude process status signal on the output line at the remote sensor so as to transfer status information about the process status to the central control station; (C) simultaneously impressing a periodic low-amplitude low-frequency diagnostic condition signal on the output line at the remote sensor so as to transfer diagnostic information about an operating condition of the remote sensor to the central control station; (D) monitoring the electrical state of the output line at the central control station to detect the level of the non-periodic high-amplitude process status signal so as to receive status information about the process status at the central control station; and (E) monitoring the electrical stat

Abstract: A mounting for a solderable component module (SCM.TM.) interconnect includes an elongated trench or blind via for receiving an edge of the module. The interconnect may be adjusted to reduce the parasitic inductance associated with the connection of the SCM interconnect and the motherboard. Preferably, the design of the finger connectors associated with the SCM interconnect or other board module can be adjusted to reduce parasitic inductance. Alternatively, the capacitance associated with the SCM interconnect or motherboard may be adjusted. The SCM interconnect preferably includes finger connectors which have a rectangular shape. The finger connectors preferably have a shape wherein the length is greater than the width and have an enhanced thickness which reduces parasitic inductance. The finger connectors are spaced close together.