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 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: 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.

Abstract: A cable reel assembly in an electric vehicle supply equipment (EVSE) having a reel around which a cable is coiled. A shaft supporting the reel bears discs that rotate with the reel, and calipers coupled to the discs stop them and the reel from rotating. The power L1 and L2 conductors in the cable are electrically connected to the discs, and the calipers are electrically connected to the power source for the EVSE so that the calipers provide mechanical and electrical connection when actuated. Optionally, slip rings coupled to the shaft are connected to the control pilot and proximity signal conductors in the cable. Thus, during cable re traction, the control pilot and proximity signals are still provided to the EVSE, but the power conductors are decoupled from the power source. Only when the calipers are actuated to brake the discs is current flow permitted.

Abstract: A distributed energy management method and system 100 are disclosed for managing a charge rate of an array of EVSEs 140 that share a common power source. In the disclosed method and system, control of the power sharing is distributed at the individual EVSE level. For example, each EVSE includes a communication device 540 and a controller 530. The communication device is used to receive a signal relating to a present current capacity utilization of the shared circuit, such as an indication of availability or unavailability of current capacity on the shared circuit. The controller is configured to generate a variable update interval, and initiate adjustment of the charge rate of the EVSE according to the variable update interval based on the present current capacity utilization as indicated by the received signal.

Abstract: The invention provides consistent settings between local and remote parameter adjustments of both local and remote HMI. A dial (4) is superimposed on a bistable display substrate (2), having an indicator (7) configured to be manually aligned with a displayed character representing a manual setting of a parameter value for controlling local equipment. A network interface (18) is connected over a communications network (17) to a remote HMI (16), configured to receive a new parameter value for controlling the local equipment (25). A controller (14) samples the current position of the indicator (7) of the dial (4), and provides a control input signal (20) to the bistable display substrate (2) to control a display of the new parameter value in the current position of the indicator (7) of the dial (4) and to provide the new parameter value to the local equipment (25).

Abstract: A circuit measures temperature in a charging handle 150 of an electric vehicle charging station (EVSE) 100. A temperature sensor is connected between a control pilot line 115 and ground line G in the charging handle of the EVSE. The control pilot line transmits a square wave signal CP having positive and negative portions, to an electric vehicle, according to the SAE J1772 standard. A temperature monitor 300 in the EVSE, coupled to a pilot signal measurement circuit 230 in the EVSE, measures the negative portions of the square wave signal resulting from the temperature sensor conducting current in response to changes in temperature in the handle. Temperature measurement of the charging handle is achieved without significant added cost or complexity, by reusing existing components in the EVSE, with little or no modification required to EVSE electronics, and minimal modification of the handle.

Abstract: A temperature sensor 120 automatically shuts down charging operations in response to a temperature increase in a charging handle 150 of an electric vehicle charging station 100. The temperature sensor is connected between a ground conductor and a high voltage conductor L1 in the charging handle. The charging handle includes a return conductor L2/N. The temperature sensor includes a thermistor R1-NTC that changes its resistance in response to an increase in temperature in the charging handle. A portion of current in the high voltage conductor is diverted to the ground conductor, instead of the return conductor, in response to the thermistor sensing a temperature increase, thereby causing a ground fault detector 160 to trip in the charging station.

Abstract: An add-on adapter 110 enables a single charging port 102 of an electric vehicle charging station 100 to simultaneously charge two electric vehicles. An adapter controller 120 determines the available charging rate offered by the charging station. Electric vehicle charging handles 150A, 150B are determined to be connected to the electric vehicles. A charge sharing control circuit 300 in the adapter controller, determines modified available charging rates to be offered for simultaneously charging the electric vehicles. The modified available charging rates are based on the connection states of the electric vehicles and the available charging rate offered by the charging station. The adapter controller controls two contactors 130A, 130B to switchably connect a charging station power socket to the electric vehicle charging handles, to provide shared power at the determined modified available charging rate to the electric vehicles, for simultaneous charging.

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.

Abstract: A distributed energy management method and system 100 are disclosed for managing a charge rate of an array of EVSEs 140 that share a common power source. In the disclosed method and system, control of the power sharing is distributed at the individual EVSE level. For example, each EVSE includes a communication device 540 and a controller 530. The communication device is used to receive a signal relating to a present current capacity utilization of the shared circuit, such as an indication of availability or unavailability of current capacity on the shared circuit. The controller is configured to generate a variable update interval, and initiate adjustment of the charge rate of the EVSE according to the variable update interval based on the present current capacity utilization as indicated by the received signal.

Abstract: The invention provides consistent settings between local and remote parameter adjustments of both local and remote HMI. A dial (4) is superimposed on a bistable display substrate (2), having an indicator (7) configured to be manually aligned with a displayed character representing a manual setting of a parameter value for controlling local equipment. A network interface (18) is connected over a communications network (17) to a remote HMI (16), configured to receive a new parameter value for controlling the local equipment (25). A controller (14) samples the current position of the indicator (7) of the dial (4), and provides a control input signal (20) to the bistable display substrate (2) to control a display of the new parameter value in the current position of the indicator (7) of the dial (4) and to provide the new parameter value to the local equipment (25).

Abstract: An add-on adapter 110 enables a single charging port 102 of an electric vehicle charging station 100 to simultaneously charge two electric vehicles. An adapter controller 120 determines the available charging rate offered by the charging station. Electric vehicle charging handles 150A, 150B are determined to be connected to the electric vehicles. A charge sharing control circuit 300 in the adapter controller, determines modified available charging rates to be offered for simultaneously charging the electric vehicles. The modified available charging rates are based on the connection states of the electric vehicles and the available charging rate offered by the charging station. The adapter controller controls two contactors 130A, 130B to switchably connect a charging station power socket to the electric vehicle charging handles, to provide shared power at the determined modified available charging rate to the electric vehicles, for simultaneous charging.

Abstract: A temperature sensor 120 automatically shuts down charging operations in response to a temperature increase in a charging handle 150 of an electric vehicle charging station 100. The temperature sensor is connected between a ground conductor and a high voltage conductor L1 in the charging handle. The charging handle includes a return conductor L2/N. The temperature sensor includes a thermistor R1-NTC that changes its resistance in response to an increase in temperature in the charging handle. A portion of current in the high voltage conductor is diverted to the ground conductor, instead of the return conductor, in response to the thermistor sensing a temperature increase, thereby causing a ground fault detector 160 to trip in the charging station.

Abstract: A circuit measures temperature in a charging handle 150 of an electric vehicle charging station (EVSE) 100. A temperature sensor is connected between a control pilot line 115 and ground line G in the charging handle of the EVSE. The control pilot line transmits a square wave signal CP having positive and negative portions, to an electric vehicle, according to the SAE J1772 standard. A temperature monitor 300 in the EVSE, coupled to a pilot signal measurement circuit 230 in the EVSE, measures the negative portions of the square wave signal resulting from the temperature sensor conducting current in response to changes in temperature in the handle. Temperature measurement of the charging handle is achieved without significant added cost or complexity, by reusing existing components in the EVSE, with little or no modification required to EVSE electronics, and minimal modification of the handle.

Abstract: A synthetic fault signal generator assembly is remotely located on a branch circuit downstream from a circuit breaker protecting a load. The synthetic fault signal generator assembly is configured to detect an improper circuit condition that is not independently detected, detectable, or actionable by the circuit breaker such as, for example, a load or outlet receptacle specific problem that can lead to equipment damage or property damage if not mitigated. In response to the improper circuit condition being detected, the synthetic fault signal generator assembly generates a synthetic fault signal, which causes the circuit breaker to trip. The synthetic fault signal generator assembly can inject the synthetic fault signal into the branch circuit to provide the synthetic fault signal to the circuit breaker.

Abstract: A method detects a shorted charging cable of an electric vehicle charging station. A charging cable of the electric vehicle charging station is determined to not be connected to an electric vehicle. An impedance test may then be performed between conductors of the charging cable while not connected to an electric vehicle. A contactor between a source of electrical power and the conductors is prevented from closing, in response to detecting a short between the conductors, and a warning signal is output. The impedance test is disabled in response to receiving a signal indicating that the charging cable has become connected to an electric vehicle, so as to not interfere with normal charging. In this manner, by detecting a short circuit in the charging cable before the contactors are closed, the contactor's contacts are prevented from becoming welded closed by a short circuit in the charging cable.

Abstract: A cable reel assembly in an electric vehicle supply equipment (EVSE) having a reel around which a cable is coiled. A shaft supporting the reel bears discs that rotate with the reel, and calipers coupled to the discs stop them and the reel from rotating. The power L1 and L2 conductors in the cable are electrically connected to the discs, and the calipers are electrically connected to the power source for the EVSE so that the calipers provide mechanical and electrical connection when actuated. Optionally, slip rings coupled to the shaft are connected to the control pilot and proximity signal conductors in the cable. Thus, during cable re traction, the control pilot and proximity signals are still provided to the EVSE, but the power conductors are decoupled from the power source. Only when the calipers are actuated to brake the discs is current flow permitted.