Abstract: The present invention provides an improved hybrid motor starter that extends the expected life of the main motor contacts of a standard contactor by reducing arcing during opening and closing of the main motor contacts and permits the use of physically smaller solid state switching devices and secondary contacts that have electrical ratings significantly lower than the standard contactor. The use of smaller solid state switching device and secondary contacts that have lower electrical ratings is permitted by minimizing the time at which these devices are exposed to full motor currents.

Abstract: The system and method for dynamically reducing the peak electromagnetic interference produced by a group of electrical or electronic switching devices connected to a common communications bus. The system and method includes a fixed range of frequencies that includes frequencies emitted by the group of switching devices during normal operation and subranges of frequencies within the fixed range of frequencies, each subrange of frequencies being associated with a unique bus address of one switching device in the group of switching devices. Each subrange of frequencies being determined by the unique bus address of its associated switching device and characteristic weights dynamically determined and/or assigned to its associated switching device and/or load by a microprocessor implemented algorithm.

Abstract: A system and method are provided to perform current sensor error compensation. The system and method involve obtaining a current measurement of a current on a circuit from a current sensor; obtaining a voltage measurement of a voltage associated with the current from a voltage sensor; determining a fundamental frequency of the voltage from the voltage measurement; and performing error compensation on the current measurement based on the determined fundamental frequency to produce a corrected current measurement. The current sensor error compensation may be performed to correct current measurements in a motor system, such as in a motor overload relay, at a low cost by using functionality already available in the system.

Abstract: A method of performing temperature-based diagnostics for motor starters within a physical grouping of motor starters is performed by determining a presently expected temperature operating range for each starter based on measuring operating temperatures of the starters; measuring their current draws, and evaluating the temperature and load draw data in light of compensation values assigned for the known power ratings of the starter and the starter's physical location within the grouping. With the presently expected temperature operating range of the starter determined, and the periodic monitoring of starter temperatures, when an individual starter's temperature exceeds its expected range, a diagnostic warning will be issued for that starter and/or for the control panel itself as a guide for preventative maintenance. Alternately, the warning may be issued for an unexpected temperature rise for a given rise in current draw, or for values exceeding an expected rate of temperature change.

Abstract: In accordance with an example embodiment of the invention, in an overload relay for a three-phase motor, an adjusted threshold for detected current phase unbalance is dynamically determined at which the relay will be tripped. The adjusted threshold is a function of a ratio of an average of currents in the three-phases to the rated full load current of the motor, i.e., motor load. As the motor load decreases, the adjusted current phase unbalance threshold is increased, causing the resulting trip time to increase, thereby increasing motor run time and reducing downtime.

Abstract: The present invention provides an improved hybrid motor starter that extends the expected life of the main motor contacts of a standard contactor by reducing arcing during opening and closing of the main motor contacts and permits the use of physically smaller solid state switching devices and secondary contacts that have electrical ratings significantly lower than the standard contactor. The use of smaller solid state switching device and secondary contacts that have lower electrical ratings is permitted by minimizing the time at which these devices are exposed to full motor currents.

Abstract: A system and method are provided to perform current sensor error compensation. The system and method involve obtaining a current measurement of a current on a circuit from a current sensor; obtaining a voltage measurement of a voltage associated with the current from a voltage sensor; determining a fundamental frequency of the voltage from the voltage measurement; and performing error compensation on the current measurement based on the determined fundamental frequency to produce a corrected current measurement. The current sensor error compensation may be performed to correct current measurements in a motor system, such as in a motor overload relay, at a low cost by using functionality already available in the system.

Abstract: A system and method is provided to monitor wear on a power factor correction capacitor in a motor system. The system and method obtains a baseline inductance angle, reactive power or power factor corresponding to a baseline power factor correction by the capacitor in the circuit; monitors a current supplied to the motor at a location upstream of the capacitor; monitors a voltage supplied to the motor, and determines a present inductance angle, reactive power or power factor based on the monitored current and voltage. The present inductance angle, reactive power or power factor corresponds to a present power factor correction by the capacitor.

Abstract: In accordance with an example embodiment of the invention, in an overload relay for a three-phase motor, an adjusted threshold for detected current phase unbalance is dynamically determined at which the relay will be tripped. The adjusted threshold is a function of a ratio of an average of currents in the three-phases to the rated full load current of the motor, i.e., motor load. As the motor load decreases, the adjusted current phase unbalance threshold is increased, causing the resulting trip time to increase, thereby increasing motor run time and reducing downtime.

Abstract: A method of performing temperature-based diagnostics for motor starters within a physical grouping of motor starters is performed by determining a presently expected temperature operating range for each starter based on measuring operating temperatures of the starters; measuring their current draws, and evaluating the temperature and load draw data in light of compensation values assigned for the known power ratings of the starter and the starter's physical location within the grouping. With the presently expected temperature operating range of the starter determined, and the periodic monitoring of starter temperatures, when an individual starter's temperature exceeds its expected range, a diagnostic warning will be issued for that starter and/or for the control panel itself as a guide for preventative maintenance. Alternately, the warning may be issued for an unexpected temperature rise for a given rise in current draw, or for values exceeding an expected rate of temperature change.

Abstract: An EVSE is equipped with voltage and current monitors to monitor V and I values over the time of charging. Normal V & I charging values for EV charging have been previously established and plotted as a threshold curve. During present charging, the V and Z values are plotted and compared to the threshold values and the slope of the V/I curve. If present value of V is less than the threshold value, or drops over time, or the Z value increases over time; current (I) to the EV is reduced and a new V/I curve is plotted. Slope of the new V/I curve is compared to the threshold and also checked for change of slope over time. If the new V/I curve slope is greater than the threshold slope, or is changing over time, corrective action is taken.

Abstract: The system and method for dynamically reducing the peak electromagnetic interference produced by a group of electrical or electronic switching devices connected to a common communications bus. The system and method includes a fixed range of frequencies that includes frequencies emitted by the group of switching devices during normal operation and subranges of frequencies within the fixed range of frequencies, each subrange of frequencies being associated with a unique bus address of one switching device in the group of switching devices. Each subrange of frequencies being determined by the unique bus address of its associated switching device and characteristic weights dynamically determined and/or assigned to its associated switching device and/or load by a microprocessor implemented algorithm.

Abstract: The overload relay units within a motor control group have the timing function for their motor thermal memories under the control of a central controller in communication with the overload relays. Thus expensive timing components and control of timestamps can be removed from individual overload relays. Further reduction of individual overload relay components can be accomplished by removing the nonvolatile memory function from the individual overload relays and allowing the central controller to perform the nonvolatile memory functions for the overload relays. The motor thermal model function for the overload relays can remain in the overload relays or might be moved to the central controller if communication bandwidth permits.

Abstract: A system to detect application conditions exceeding SELV design limitations and to subsequently warn or take action. A pulse detector is coupled to the switching pole of an output FET of a SELV power supply through an optocoupler and tracks when the FET is commutated off to block conduction. If a pulse occurs more than once in a given period the power supply is declared to be outside of SELV design parameters and warnings are issued or actions are taken.

Abstract: An adapter which can be retrofit onto the downstream end of a standard Electric Vehicle Supply Equipment connector is used to control power consumption of an Electric Vehicle charging facility by intercepting the Control Pilot Signal going to the Electric Vehicle and issuing a new Control Pilot Signal to the Electric Vehicle which is particularly tailored for the present use, requirements and limitations of the delivery system capability. The adapter has wireless communication capability, requires no wiring to and from the Electric Vehicle Supply Equipment, is independent of any proprietary designs of the Electric Vehicle Supply Equipment and adds no constraints or requirements to the Electric Vehicle Supply Equipment.

Abstract: A simple, economically efficient, synchronized switching system for control of a three phase motor contactor utilizes only Voltage monitoring to determine zero crossings and knowledge of the sinusoidal power waveforms and operational delay period of the contactor, to synchronize operation of the contacts at low power. The phases can be serially utilized for zero crossing detection upon Close or Open commands, so as to spread the wear over each set of contacts. Expensive metal at the contact surfaces can therefore be used more efficiently. For arc energy reduction upon contact opening, knowledge of Line-Load Voltage on at least one phase can be used to derive an empirical determination of the voltage angle at opening which yields the lowest arc energy.

Abstract: In an electromagnetically controlled actuator of an electrical contactor, switching is done by the actuator with a set of fixed contacts and a set of movable contacts. The movable contacts are carried on a movable contact carrier. The movable contact carrier is coupled to and driven by an armature surrounded by a coil. The armature carries a coupling shaft, and the coupling shaft carries at least part of a bistable coupling mechanism which joins the armature to the movable contact carrier and allows the movable contact carrier and armature to keep the fixed and movable contacts separated when a short circuit current creates a contact welding situation.

Abstract: A system and method for evaluating and altering, if necessary, the potential for a cyber security attack on an individual embedded device located on a local network assumed to be protected from outside cyber threats. In a first level of potential exposure the system attempts to send an outgoing message to a known IP address on a network outside the local network. If the outgoing messages are confirmed as received the embedded device has access to outside networks. In a second level of potential exposure the known outside IP address attempts to send an incoming message to the embedded device. If the incoming message is received the embedded can be accessed from an external network.

Abstract: The present invention provides a method of using a current transformer for a temperature sensing device. The method determines the temperature of the current transformer's secondary winding by injecting a DC current into the secondary winding, measuring a voltage across the secondary winding, calculating the resistance of the secondary winding from the voltage induced into the secondary winding by the injected DC current and determining the secondary winding temperature by calculations or a comparison with verified resistance/temperature combinations.

Abstract: Method and system for protecting induction motors from stalled start conditions provide a motor overload protection device that includes a stalled start detector capable of differentiating long start from stalled start conditions. This helps the motor overload protection device identify a stalled start condition right away and trip immediately rather than allowing the motor to continue drawing locked rotor current for the duration of the startup interval. Such a motor overload protection device may be used with any suitable multiphase induction motors, including two-phase motors, three phase motors, and the like. And because only the motor phase currents are used to detect the stalled start condition, the motor overload protection device disclosed herein does not require voltage phase shift information and/or motor speed measurements, thereby simplifying overall management of the motor.