Abstract: An electrical propulsion system includes an electrical motor configured to drive one or more propellers of the aircraft, a capacitor configured to stabilize a direct current (DC) bus voltage, a first inverter circuit coupled to the capacitor and configured to convert the DC bus voltage to alternate current (AC) voltages to drive a first set of stator windings of the electrical motor, in response to a first pulse width modulation (PWM) vector, and a second inverter circuit coupled to the capacitor and configured to convert the DC bus voltage to AC voltages to drive a second set of stator windings of the electrical motor, in response to a second PWM vector. The first PWM vector and the second PWM vector are substantially equal and opposite vectors.

Abstract: A drive control device is applicable to a vehicle including a first motor which drives a first wheel and a second motor which drives a second wheel. The drive control device includes a sensor, a torque setting section, an anomaly detection section, and an information output section. The sensor detects information about the drive control device. The torque setting section sets upper limit values of torques that can be generated by the first motor and the second motor based on the information detected by the sensor. The anomaly detection section detects an anomaly in the drive control device. In response to the anomaly detection section detecting the anomaly, the information output section outputs, to the torque setting section, setting information that sets the upper limit values of the torques of the first motor and the second motor to a common predetermined value, as the information.

Abstract: A detection and protection circuit includes: a comparator, six resistors, and two diodes. A first resistor is connected to a second resistor. The second resistor (30) is grounded. A positive input end, a negative input end, a power supply end, a ground end, and an output end of the comparator are connected to a third resistor, a fourth resistor, a power management device power supply pin, the ground, and a main controller. The other end of the third resistor is connected between the first resistor and the second resistor. The other end of the fourth resistor is connected to the first resistor. A first power supply is connected between the fourth resistor and the first resistor. A fifth resistor is connected to a sixth resistor. The sixth resistor (70) is grounded. The other end of the fifth resistor is connected to the main controller.

Abstract: Electrically driven mobile compressor or pump, comprising at least one compressor element or pump element for supplying a pressurised fluid to a network of consumers of such pressurised fluid; an electric drive motor with a variable speed control coupled to the compressor element or pump element and a controller for the variable speed control of the electric drive motor as a function of the flow rate of compressed gas and/or pressure demanded by the network, and a connection for connection of the compressor or pump to an electricity supply source, and the controller is provided with an algorithm with which the electric current drawn from the supply source can be limited to a set or adjustable maximum value by controlling the speed.

Abstract: A motor drive unit for driving a motor of a motorized window treatment may comprise software-based and hardware-based implementations of a process for detecting and resolving a stall condition in the motor, where the hardware-based implementation is configured to reduce power delivered to the motor if the software-based implementation has not first reduced the power to the motor. A control circuit may detect a stall condition of the motor, and reduce the power delivered to the motor after a first period of time from first detecting the stall condition. The motor drive unit may comprise a stall prevention circuit configured to reduce the power delivered to the motor after a second period of time (e.g., longer than the first period of time) from determining that a rotational sensing circuit is not generating a sensor signal while the control circuit is generating a drive signal to rotate the motor.

Abstract: A milling machine, system, and method for implementing an exit cut operation raises a rotor from a state where the rotor contacts ground surface material responsive to a control input at an operator control interface of the milling machine. The rate at which the rotor is raised can increase as the rotor is raised. When the rotor is determined to have reached a top surface of the ground surface material the rotor can be raised at a maximum rate.

Abstract: A power conversion circuit having a solid-state circuit breaker integrated therein is disclosed. With a disconnect switch between a utility source and the power conversion apparatus described for meeting UL489, the power conversion circuit includes an input connectable to an AC source, a rectifier circuit connected to the input to convert an AC power input to a DC power, and a DC link coupled to the rectifier circuit to receive the DC power therefrom. The rectifier circuit comprises a plurality of phase legs each including thereon an upper switching unit and a lower switching unit, wherein at least one of the upper and lower switching units on each phase leg comprises a bi-directional switching unit that selectively controls current and withstands voltage in both directions, so as to provide a circuit breaking capability that selectively interrupts current flow through the rectifier circuit, while maintaining original power conversion functionalities.

Abstract: Systems and methods described herein a sensor integrated circuit (IC) is provided having a protection circuit configured to protect circuitry within the IC from a transient pulse on a connection (i.e., power pin) to a power supply that is configured to provide power to the IC. The protection circuit can be disposed in a current path between a power pin of the IC and additional circuitry or nodes within the IC, such as but not limited to, a regulator or a bi-directional current source. The protection circuit includes a reverse blocking device having a first terminal coupled to the power supply at which a predetermined power supply voltage is provided and a second terminal coupled to an input of the regulator.

Abstract: An electrically operable clipper has a body portion and a head portion, wherein the head portion includes a movable cutter and a fixed comb. The clipper includes an internally located electric motor operable to move the movable cutter. The clipper further includes an operating switch movable between an off position, an operating position and a reset position, wherein the reset position operates a motor reset module of the clipper.

Abstract: Systems and methods are provided for a three-phase compensation system, whereby an electric circuit is configured to be connected with three input phases of a power source and to supply three respective output phases, said electric circuit further configured to compensate for one or two malfunctioning input phases of said three input phases by supplying current from a functioning input phase of said three input phases to replace a malfunctioning input phase.

Abstract: A motor drive device includes: a converter which converts AC power of an AC power source side to DC power and outputs the same to a DC link; a DC link capacitor; an inverter in which each switching element is controlled based on a switching drive signal supplied, thereby performing power conversion between DC power of the DC link and AC power of a motor side; a DC/DC converter which converts DC power of the DC link to DC power for a control power source; a servo motor control circuit which outputs the switching drive signal; a torque cut-off circuit which cuts off source of each switching drive signal to each switching element, thereby stopping a motor when not receiving a safety signal; and a safety monitor circuit which stops transmission of the safety signal during an abnormality of the torque cut-off circuit.

Abstract: An inverter control device and inverter control method are such that, when there is a possibility of induction voltage caused by a multi-phase motor exceeding a breakdown voltage of a switching element of an inverter, two of three phases are first interrupted at an appropriate timing in order to restrict induction voltage when shifting from a three-phase short circuit to an all-phase interruption, after which a shift is made to an all-phase interruption at a timing at which currents of the three phases reach the vicinity of zero, whereby a leap in a direct current bus voltage is restricted.

Abstract: For operating multi-axis drive assemblies more reliably even in a field weakening range, a current conversion device is proposed which includes a voltage-source DC link, a plurality of inverters having each a DC input side connected to the voltage-source DC link and AC output-side terminals for connection to an electric motor, and a control device configured to short-circuit each of the inverters. A measurement device measures an electrical variable at each of the inverters. The control device determines based on the measured electrical variables independently for each of the inverters directly or indirectly whether a particular inverter is feeding energy into the voltage-source DC link, and short-circuits, when this is the case, the particular inverter independently of the other inverters. A corresponding operating method is also disclosed.

Abstract: A line-to-ground fault location detector detects, based on a difference between a current flowing from a power transmission circuit to a load circuit, and a current flowing from the load circuit to the power transmission circuit, whether a line-to-ground fault is occurring at a power-transmission-circuit side or a load-circuit side. A contactor controller opens a first contactor when the load circuit detects the occurrence of the line-to-ground fault, and when a line-to-ground fault location detector detects that a location of the line-to-ground fault is at the power-transmission-circuit side, the contactor controller maintains the open state of the first contactor even if an operation to instruct closing of the first contactor is made after the first contactor is opened.

Abstract: A connection system forms an electric path through which power transmission is performed between an electric vehicle and a power conditioner system. The electric vehicle includes a relay circuit that opens the electric path if a voltage equal to or above a predetermined value is applied between voltage output terminals. The connection system includes a fuse that blows in response to a current input thereto equal to or above a predetermined value and a resistor connected in parallel with the fuse.

Abstract: A method for detecting a grid event is provided. The method includes sampling grid voltage and grid current over a fixed period of time; determining grid impedance at one or more frequencies using the sampled grid voltage and the sampled grid current; comparing the grid impedance at the one or more frequencies to a known expected grid impedance at the one or more frequencies; and detecting a grid event based on the comparison.

Abstract: There is provided a grounding detection device and method. The grounding detection device may include an insulation tester and a grounding resistance providing unit. The insulation tester may be mounted in a first cabinet, electrically connected to a positive busbar and a negative busbar to detect an equivalent busbar-to-ground resistance, and grounded via the first cabinet. The grounding resistance providing unit may be mounted at least in part in a second cabinet different from the first cabinet, electrically connected to at least one of the positive busbar and the negative busbar to provide a grounding resistance, and grounded via the second cabinet. The insulation tester may determine, based on resistance values of the equivalent busbar-to-ground resistance and the grounding resistance, whether there is a ground fault or not for the insulation tester, the first cabinet, and the second cabinet.

Abstract: A circuit includes a current source intended to be series-connected with a load between two terminals of application of a first D.C. voltage. An element limits the voltage across the load and a circuit controls the value of the current in the current source with the current flowing in the element.

Abstract: Congruent power and timing signals in a single electronic device. In an embodiment, a circuit may include just one isolation transformer operable to generate a power signal and a timing signal. On the secondary side, two branches may extract both a power signal and a clock signal for use in the circuit on the isolated secondary side. The first branch may be coupled to the transformer and operable to manipulate the signal into a power signal, such as a 5V DC signal. Likewise, the second circuit branch is operable to manipulate the signal into a clock signal, such as a 5 V signal with a frequency of 1 MHz. By extracting both a power supply signal and a clock signal from the same isolation transformer on the secondary side, valuable space may be saved on an integrated circuit device with only having a single winding for a single isolation transformer.

Abstract: The system has a driving circuit for the motor of the electric fan, coupled to the electrical system of a motor vehicle and having a plurality of controlled electronic switches, and an electronic control unit arranged to control the driving circuit in such a way as to cause the flow in the motor of a variable average current capable of producing a required speed of rotation, in accordance with a predetermined relationship or function. The control unit is designed to store a predetermined threshold of rotation speed, and to control the motor through the associated driving circuit in such a way that when the rotational speed of the motor exceeds the threshold the driving circuit causes electrical braking of the motor.

Abstract: In various embodiments a circuit arrangement is provided, having a bridge circuit including at least two switches connected in series; a bridge node which may provide a phase voltage arranged between the at least two switches; an electric motor having at least one phase winding coupled with the bridge node; a decoupling switch; a controller, wherein in an error case the controller may be configured to switch off the at least two switches, to determine whether a predefined condition is satisfied, and to one of delayed switching off the decoupling switch; and switching off the at least two switches and the decoupling switch simultaneously, depending upon whether the predefined condition is satisfied; wherein the controller may determine that the predefined condition is satisfied when the decoupling switch may be switched off without damage from the current applied to it when the at least two switches are switched off.

Abstract: A system includes a refrigerant compressor including an electric motor, a current sensor that measures current flow to the electric motor, a switching device configured to close and open to allow and prevent current flow to the electric motor, respectively, a maximum continuous current (MCC) device that includes a resistance corresponding to a maximum continuous current for the electric motor, and a motor protection module. The motor protection module communicates with the MCC device, the current sensor, and the switching device and determines a first MCC value for the electric motor as a function of the resistance of the MCC device. The motor protection module also selectively sets a predetermined MCC to the first MCC and controls the switching device based on a comparison of the current flow to the electric motor and the predetermined MCC.

Abstract: In a memory, the surface temperature and the internal resistance of an assembled battery detected under the condition where a difference between the surface and the internal temperature is within a predetermined value are stored, and an internal temperature diagnosis unit that diagnoses whether or not the internal temperature estimated by an internal temperature estimation unit is correct, detects the internal resistance with an internal resistance calculation unit when the internal temperature estimation unit estimates the internal temperature, searches for an internal resistance corresponding to the surface temperature equal to the estimated internal temperature value from among the stored internal resistances, and diagnoses the estimated internal temperature value based upon the result of comparison of a search result of the internal resistance and the internal resistance detected during internal temperature estimation.

Abstract: Improved motor starters and/or overload electronics are presented for industrial automation systems, HVAC systems, pumping systems, and/or similar implementations. Protective devices can be configured to offer substantially automatic control and/or protection for motors without first being manually calibrated, or properly calibrated, for the motor. An overload, motor starter, and/or other motor protection and/or control device can accommodate substantially universal voltage input, true power characteristic sensing for status output/annunciation, integrated damper control, and substantially automated protection and/or trip point selection and/or protective parameter calculation and implementation with reference to startup values and/or system parameters such as full load amperage (FLA), motor classification, motor horse power, monitored current, monitored voltage, and true power characteristics, including power factor values.

Abstract: A method to avoid a single point of failure in a system that includes at least two monitoring devices, at least two power supplies and a switching device coupled between the monitoring devices and the power supplies. The method includes performing a test that can determine if two monitoring devices are receiving power from the power supply, generating an error code and varying a position of one or more switches in a switching device based on the error code.

Abstract: For each phase of a controller, semiconductor switches comprise a high side switch and a low side switch. A direct current voltage bus provides electrical energy to the semiconductor switches. A measuring circuit is adapted to measure the collector-emitter voltage or drain-source voltage for each semiconductor switch of the controller. A data processor determines that a short circuit in a particular semiconductor switch is present if the measured collector-emitter voltage or measured source-drain voltage for the particular semiconductor switch is lower than a minimum threshold and if an observed current associated with the particular semiconductor switch has an opposite polarity from a normal operational polarity. A driver simultaneously activates counterpart switches of like direct current input polarity that are coupled to other phase windings of the electric motor, other than the particular semiconductor switch, to protect the electric motor from potential damage associated with asymmetric current flow.

Abstract: A method to avoid a single point of failure in a system that includes at least two monitoring devices, at least two power supplies and a switching device coupled between the monitoring devices and the power supplies. The method includes performing a test that can determine if two monitoring devices are receiving power from the power supply, generating an error code and varying a position of one or more switches in a switching device based on the error code.

Abstract: In a power converter a controller determines that an AC motor is in an abnormal state when a voltage of each phase of the AC motor detected by a voltage detector is in an unbalanced state where the voltage exceeds a predetermined value, and turns an opening/closing unit OFF to prevent damage generated in the AC motor from becoming worse. Moreover, the controller determines abnormality of the opening/closing unit based on a current of each phase detected by a current detector, and the controller performs control to reduce the number of revolutions of the AC motor upon determining that at least one of the AC motor and the opening/closing unit is in an abnormal state.

Abstract: The present invention is a method and system for monitoring the continuous flow of power delivered by multiple DC Direct current operated starter motors used to start engine driven electrical generators. The method and system comprise the closing of a starter battery system and an associated starter control switch, causing the starter battery system to discharge through a shunt whereby current is fed into a starter motor. The shunt is optionally provided as a precision resistor with a pre-calibrated voltage drop in millivolts DC proportional to a current passing through it. The shunt directs current to a meter relay, which is calibrated by establishing two set points, or desired trigger ranges, for the meter relay. If the current falls outside a range established by the two set points, then a meter relay alarm output is activated; and, if the current remains within the range, then the meter relay alarm output is not activated.

Abstract: In a motor driving device, a driving switching element is connected in series with a motor between a power source and a ground, and operated by a PWM signal outputted from a control circuit. A return current path forming unit is connected in parallel with the motor to allow a return current when the driving switching element is turned off. A series circuit of a current flow restriction element and a switch is connected in parallel with the return current path forming unit. A disconnection determination unit prohibits output of the PWM signal and closes the switch of the series circuit when a voltage applied to the motor does not fluctuate according to the PWM signal, and determines the disconnection of the motor on condition that the voltage detected in that state indicates a change across a second threshold.

Abstract: A compressor monitoring system includes current and voltage monitors, current and voltage averaging modules, a control module, and a switch. The current monitor measures a current drawn by a motor of a compressor. The current averaging module generates first and second average current values based on the current measured by the current monitor. The voltage monitor measures a utility power voltage. The voltage averaging module generates first and second average voltage values based on the voltage measured by the voltage monitor. The control module selectively generates a fault signal when a first ratio is greater than a first predetermined threshold and a second ratio is less than a second predetermined threshold. The first ratio is based on the first and second average current values. The second ratio is based on the first and second average voltage values. The switch deactivates the motor when the fault signal is generated.

Abstract: A system and method for detecting ground faults in an AC motor drive is disclosed. A fault detection and protection system for an AC motor drive includes current sensors to measure first and second phase output currents, a voltage sensor to measure a DC link voltage, and a desaturation control circuit to determine a voltage and associated current across PWM inverter switches for a third phase of the output. A controller compares the first and second phase currents, the measured DC link voltage, and the voltage across the PWM inverter switches on the third phase, to a plurality of thresholds. The controller detects a ground fault on one of the first, second, and third phases of the three phase output to the AC motor based on the comparisons of the first and the second phase currents, the DC link voltage, and the voltage across the switches to the thresholds.

Abstract: The invention concerns a method for detecting a fault in a rotating field machine, in which current components are analysed in a flux-based, particularly rotor-flux-based, coordinate system a flux-forming current component being subjected to a frequency analysis in the flux-based, particularly rotor-flux-based, coordinate system. It is endeavored to provide a simple method for an early detection of faults. For this purpose, a current operating point is detected for at least one predetermined supply frequency (fsp), said operating point being compared to a former operating point.

Abstract: A protection relay for an electrical switching apparatus for a load includes a number of voltage sensors structured to sense voltage applied to the load, a number of current sensors structured to sense current flowing to the load, and a processor cooperating with the number of voltage sensors and the number of current sensors. The processor determines a fault current available at the load. An output cooperates with the processor. The output is structured to output the determined fault current and a number of: incident energy at the electrical switching apparatus, and a personal protective equipment level operatively associated with the electrical switching apparatus. The processor determines from the determined fault current the number of: the incident energy at the electrical switching apparatus, and the personal protective equipment level operatively associated with the electrical switching apparatus.

Abstract: A leakage current masking device for use with a circuit includes at least one inductive load device coupled to the circuit and configured to supply an inductive load to the circuit, and a processor communicatively coupled to the inductive load device. The processor is configured to receive a signal representative of a current through the circuit, calculate a capacitive leakage current component of the current, and cause the inductive load device to adjust the inductive load supplied to the circuit to reduce the capacitive leakage current component.

Abstract: An automatic power-off and actuation circuit for a fan comprises a drive unit, a detection unit, a voltage-modulating unit, a comparison unit, an auto-restart unit, a regulation unit and a controlled IC, wherein the detection unit is electrically connected to the drive unit, the voltage-modulating unit is electrically connected to the detection unit, the comparison unit is electrically connected to the voltage-modulating unit, the auto-restart unit is electrically connected to the comparison unit, the regulation unit is electrically connected to the auto-restart unit and the drive unit, and the controlled IC is electrically connected to the regulation unit and the drive unit.

Abstract: Provided are compositions and materials that have varistor properties and are suitable for use in electrical stress control devices and surge arrestor devices. The compositions and materials include a polymeric material and calcined calcium copper titanate filler material and have a reversible non-linear current-voltage characteristic.

Abstract: The motor monitoring system of the present disclosure uses several calculated monitoring values to determine a status of a motor and take a predetermined action when a threshold corresponding with the monitoring value is exceeded. The threshold may be calculated by an intelligent electronic device (IED) monitoring the motor. The predetermined action may include further monitoring of the motor. The predetermined action may include monitoring equipment not directly monitored by the IED.

Abstract: A protective circuit arranged on a Printed Circuit Board (PCB) has two conductor loops. At least one supply voltage track, at least one semiconductor switch and at least one control component are arranged on the PCB. A first terminal of the control component and a first terminal of the semiconductor switch are connected electrically. A first conductor loop of the protective circuit is arranged on the PCB so that it surrounds an electrically conducting connection between the supply voltage track and the semiconductor switch and/or the control component. A second conductor loop is arranged on the PCB so that it surrounds the electrically conducting connection between the first terminal of the control component and the first terminal of the semiconductor switch, and thereby screens the same from the semiconductor switch and at least from those regions of the control component that are also connected to the supply voltage track.

Abstract: A system and method for detecting a rotor fault condition in an AC induction machine is disclosed. The system includes a processor programmed to receive voltage and current data from an AC induction machine, generate a current frequency spectrum from the current data, and identify rotor-fault related harmonics in the current frequency spectrum. The processor is also programmed to calculate a fault severity indicator using the voltage and current data, identified rotor-fault related harmonics, and motor specifications, analyze the fault severity indicator to determine a possibility of rotor fault. The processor generates an alert based on the possibility of rotor fault.

Abstract: An over-current protection device for multiple high-voltage motive devices is provided. The over-current protection device includes a comparison module and a logic operation module. The comparison module receives a plurality of voltages generated from a plurality of operating currents of a plurality of high-voltage motive devices and respectively compares the voltages with at least one reference voltage to generate a plurality of comparison results, wherein the high-voltage motive devices are solenoids, electronic clutches, or a combination of solenoids and electronic clutches. The logic operation module receives the comparison results and generates at least one control signal for a plurality of high-voltage motive device driving circuits according to the comparison results. The high-voltage motive device driving circuits respectively drive the high-voltage motive devices according to the control signal.

Abstract: A motor driving circuit receives a control pulse signal pulse-width modulated according to a target rotational speed, and drives a fan motor. A start pulse signal generating unit generates a start pulse signal having a predetermined duty ratio. A driving unit drives the fan motor by pulse width modulation according to the driving pulse signal received from a control unit. When the duty ratio of the control pulse signal is switched from zero to a nonzero value when the fan motor is in the stopped state, the control unit commences the driving operation for the fan motor. The control unit outputs, as the driving pulse signal, the start pulse signal, in a predetermined start period Ts from the commencement of the driving operation. After the start period elapses, the control unit outputs the control pulse signal as the driving pulse signal.

Abstract: A pump system. The pump system includes a pump, a motor coupled to the pump, a sensor coupled to a power source, and a controller. The motor operates the pump. The sensor detects an electrical characteristic of the power source. The controller executes a fault check, controls the motor, detects a change in the electrical characteristic, and suspends the execution of the fault check for a predetermined period of time when the detected change in the electrical characteristic is outside of a valid characteristic range.

Abstract: A ground fault sensing device for a drive system that converts direct current electrical power from a direct current power supply into alternating current electrical power and drives an electric motor with that alternating current electrical power, comprises: an extraction circuit that is connected to a power supply line of the direct current power supply via a coupling capacitor, that detects an amplitude wave that is generated when an alternating current side including the electric motor is suffering a ground fault, and that extracts the envelope of the amplitude wave; a measurement circuit that measures the voltage level of the envelope; and a determination circuit that makes a decision as to whether or not a ground fault has occurred on the alternating current side by comparing together the voltage level measured by the measurement circuit and a ground fault decision value.

Abstract: When a short-circuited FET is identified as one of low-side FETs, maximum phase voltages of three phases are detected when a steering operation is performed by a driver, and the detected maximum phase voltages of the three phases are compared with one another to identify a short-circuit phase. On the other hand, when a short-circuited FET is identified as one of high-side FETs, minimum phase voltages of the three phases are detected when a steering operation is performed by the driver, and the detected minimum phase voltages of the three phases are compared with one another to identify a short-circuit phase.

Abstract: UPS performance failure is determined independently by itself. Selective tripping can be done within a shorter time than one cycle of an AC output. A UPS converts a DC voltage to an AC voltage and supplies the AC voltage to a load device. A UPS has a control unit identifying a resistance value of an internal resistance as an internal impedance of the UPS by using an instantaneous value of an internal voltage and current and conducting a failure determination by detecting abnormal fluctuation of the value. It is preferred that an identification of the internal impedance is done through a system identification unit.

Abstract: A power conversion device includes: an inverter that drives an alternating-current motor by converting a direct-current voltage into an alternating-current voltage of an arbitrary frequency; an alternating current disconnecting switching unit connected between the inverter and the alternating-current motor; a current detector that detects an output current of the inverter; and a controller that performs on/off-control of the plural switching elements in the inverter and switching control with respect to the switching unit, based on at least a current detected by the current detector. The controller has a configuration to be able to interrupt a fault current by setting the fault current to a state of generating a current zero point, when the fault current containing a direct-current component is generated between the inverter and the alternating-current motor.

Abstract: One or more variable configuration controller (VCC) systems may produce various combinations of series or parallel couplings of coils, winding or inductive elements of an electric machine such as a generator and/or electric motor. The VCC systems include a plurality of bridge rectifiers, and a first number of switches operated to selectively couple respective pairs of coils in series from parallel on an AC side of the bridge rectifiers. The bridge rectifiers provide for automatic electrical isolation of coils on occurrence of open circuit, low voltage or short circuit conditions. A second number of switches with different performance characteristics (e.g., speed, loss) than the first number of switches may be coupled in parallel with respective ones of the first number of switches. Power factor correction may be used.

Abstract: A regulating system includes an input port having a first input terminal and a second input terminal, an output port having a first output terminal and a second output terminal, a regulating circuit, an over-current protection circuit, and an overvoltage protection circuit. The overvoltage protection circuit includes a regulating diode, a first bipolar transistor and a second bipolar transistor. The first output terminal is connected to the base of the first bipolar transistor via the regulating diode and grounded via first bipolar transistor. A base of the second bipolar transistor connects to the collector of the first bipolar transistor. The second output terminal is grounded via the second transistor. When an output voltage of the first output terminal increases over a predetermined voltage, an electrical connection between the second output terminal and ground is cut off to stop providing output voltage from the output port.

Abstract: A compressor monitoring system includes current and voltage monitors, current and voltage averaging modules, a control module, and a switch. The current monitor measures a current drawn by a motor of a compressor. The current averaging module generates first and second average current values based on the current measured by the current monitor. The voltage monitor measures a utility power voltage. The voltage averaging module generates first and second average voltage values based on the voltage measured by the voltage monitor. The control module selectively generates a fault signal when a first ratio is greater than a first predetermined threshold and a second ratio is less than a second predetermined threshold. The first ratio is based on the first and second average current values. The second ratio is based on the first and second average voltage values. The switch deactivates the motor when the fault signal is generated.