Rockwell Automation Technologies Incorporated

Eaton Corporation

Rockwell Technologies, Inc.

Rockwell International Technologies, Inc.

David M Messersmith

Thomas Arthur Nondahl

Haihui Lu

Andrew Edward Carlson

Kyle Benjamin Adkins

David Elmiger

David J Gritter

Zhenhuan Yuan

Douglas J Bader

Yutao Wang

John Herman Blakely

Daniel J Bolda

David Bradly Berman

Yanbin Zhang

Joseph A Johnson

Michael J Lemberger

William T Glaser

A system includes a relay system and a controller. The relay system includes a plurality of relays, each having a first contact on an input side of the respective relay, the input side coupled to a power source, a second contact on a load side of the respective relay coupled to a load, and a spanner configured to close the first and second contacts of the respective relay when activated by a close signal. The load sides of each of the respective relays are coupled through their respective loads. The controller is configured to measure a voltage between a spanner of a first relay and an input side of a second relay. Based on the voltage between the spanner of the first relay and the input side of the second relay, the controller determines whether an electrical weld of one of the contacts of the first relay exists.

Detecting welded relay contacts using spanner voltage measurement

A system includes a relay system and a controller. The relay system includes a plurality of relays. The controller is configured to transmit a close signal to a first relay of the plurality of relays, and to transmit a pulse signal to a second relay of the plurality of relays. The pulse signal is configured to have a sufficient electrical magnitude and duration to close the second relay when the second relay has an electrical weld, and to have an insufficient electrical magnitude and duration to close the first contact and the second contact of the second relay when the second relay has no electrical weld. The controller is also configured to measure a current flow through the second relay in response to the pulse signal; and based on the current flow through the second relay, determine whether the electrical weld exists in the second relay.

Detecting welded relay contacts using electrical pulse

A system includes a relay system and a controller. The relay system includes a plurality of relays. The controller is configured to transmit a close signal to a first relay and a second relay of the plurality of relays. The close signal is configured to close the first contact and the second contact of each of the first relay and the second relay. The controller is also configured to measure a first close time between the transmission of the close signal to the first relay and a time when the first relay closes, and to measure a second close time between the transmission of the close signal to the second relay and a time when the second relay closes. The controller is further configured to determine whether an electrical weld exists in the first relay or the second relay, based on the first and second close times.

Detecting welded relay contacts using contact close time measurement

Systems and methods are provide for detecting weld relay devices within a switching device by: closing one or more first relay devices, wherein the one or more first relay devices are configured to selectively connect and disconnect a first phase of electric power from a power source; opening one or more second relay devices and one or more third switches; detecting whether there is electric current through the one or more second relay devices; and in response to detecting that there is electric current through the one or more second relay devices, determining that the one or more second relay devices are welded.

Systems and methods for detecting welded contacts in a switch system

A non-transitory, computer-readable medium may include instructions executable by at least one processor in a computing device to cause the processor to perform operations that include transmitting, to a first power source, a command to provide power to a coil of a switching device with a fixed current profile. The operations also include receiving one or more voltage measurements associated with the coil during a period of time, determining whether the voltage measurements associated with the coil indicate that one or more movable contacts of the switching device are at least partially welded to one or more contacts of an electric circuit, and transmitting an additional command to a second power source to disconnect a current to the coil in response to determining that the voltage measurements indicate that the movable contacts of the switching device are at least partially welded to the contacts of the electric circuit.

Systems and methods for detecting welded contacts in an electromagnetic switch system

A method may include receiving a command to move one or more armatures of a switching device from a first position that electrically couples a first contact to a second contact to a second position that electrically uncouples the first contact from the second contact. The method may also include selecting a current zero-crossing point along an electric waveform indicative of a change in current through the first contact and the second contact as a synchronization point, determining a predicted current zero-crossing point by adding a period measurement associated with a previously detected current zero-crossing point or a previously detected line-to-line crossing point in the electric waveform to the synchronization point, and transmitting a command to the switching device to move the armatures from the first position to the second position before or at the predicted current zero-crossing point.

Predicting zero-crossings for point-on-wave (POW) switching techniques

A device includes an armature, a coil, and a circuit. The armature is configured to move between a close position that electrically couples the armature to a contact and an open position that is not electrically coupled to the contact. The coil is configured to release a voltage configured to de-magnetize the coil, thereby causing the armature to move from the close position to the open position. The circuit is configured to provide reverse driving current to the coil during a period of time when the armature moves from the close position to the open position.

Systems and methods for controlling contactor open time

A component includes first and second switches in series and connected between a power source and a coil of contacts of a safety relay. A first controller controls the first switch with a close signal that closes the first switch or a first PWM signal that opens and closes the first switch on each PWM cycle. A second controller controls the second switch with a close signal that closes the second switch or a second PWM signal that opens and closes the second switch on each PWM cycle. A PWM sensing circuit connected to the coil sends a sensed PWM signal to an input of the first and second controllers. The first controller sends the first PWM signal while the second controller sends a close signal and vice-versa. The controllers verify that the received PWM signal matches the sent PWM signal.

Dual PWM relay driver with diagnostics for functional safety system

Current transformer circuit systems and methods dynamically switch a load. The current transformer circuit includes a current source circuit including at least one current transformer to produce a current output wave. A burden circuit includes at least one burden resistor and a voltage sensor, at least a portion of the current output wave to be passed through the burden resistor, and the voltage sensor to sense a voltage across the respective at least one burden resistor. A switch circuit includes at least one switch, the switch circuit coupled to the burden circuit. A microcontroller circuit includes a microcontroller, the microcontroller circuit coupled to a power circuit and the switch circuit, the microcontroller being configured to control the switch circuit to dynamically switch a secondary loading of the at least one current transformer between the burden resistor and a low resistance load.

Systems and methods for dynamically switching a load of a current transformer circuit

A method of estimating stator resistance of an induction motor is provided. The method includes applying voltage pulses through two phase paths of the motor for a plurality of electrical cycles to inject current in the motor, wherein the voltage pulses are applied until rotor flux of the motor is substantially stabilized and measuring stator voltage and stator current in response to the applied voltage pulses for each of the plurality of electrical cycles. The method also includes calculating the stator resistance based upon the measured stator voltages and the stator currents.

Parameter estimation system and method for an induction motor

A method of estimating stator resistance of an induction motor includes applying voltage pulses through two phase paths of the motor for a plurality of electrical cycles to inject current in the motor, wherein the voltage pulses are applied until rotor flux of the motor is substantially stabilized and measuring stator voltage and stator current in response to the applied voltage pulses for each of the plurality of electrical cycles. The method also includes calculating the stator resistance based upon the measured stator voltages and the stator currents.

Systems, methods, and devices are disclosed, including an induction-motor controller having a phase path; a solid-state switch interposed on the phase path; and a controller coupled to the solid-state switch. In certain embodiments, the controller is configured to switch the solid-state switch so that the solid-state switch is conductive during a conduction angle of a cycle of an incoming AC power waveform conveyed by the phase path, calculate the conduction angle based on a generally sinusoidal reference value that has a frequency lower than a frequency of the incoming AC power waveform, and adjust the generally sinusoidal reference value based on a value indicative of flux in a load coupled to the phase path.

Control method and system with feedback indicative of load flux

The subject matter disclosed herein describes a system for controlling torque in a soft starter. In particular, torque ripple is reduced when transitioning between two different operating modes of a soft starter. A soft starter may include a first operating mode, designed for improved performance during low-speed operation of a motor, and a second operating mode, designed for improved performance during high-speed operation of the motor. However, transitioning between two different operating modes may result in significant transient currents in the motor, which, in turn, produce torque in the motor. The system described herein reduces this transient torque production in the motor.

Method and apparatus for controlling motor torque

Systems, methods, and devices are disclosed, including an induction-motor controller that has a motor controller configured to receive alternating current (AC) power with a voltage that varies generally sinusoidally and transmit the AC power during a conduction angle of a cycle of the AC power. In some embodiments, the conduction angle varies generally sinusoidally at a lower frequency than the AC power, and the motor controller may be configured to not transmit the AC power outside of the conduction angle.

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Kenosha, WI, United States of America

David M Messersmith