Abstract: A method for monitoring a fan comprises measuring power usage of the fan, determining a derivative of the measured fan power usage, tracking the derivative over time, and predicting impending fan failure based on the tracked fan power usage derivative.

Abstract: A system and method for removing energy from the rotating group in an energy storage flywheel system during flywheel system testing includes one or more sensors is operable to sense operational parameters of the energy storage flywheel and to supply a sensor signals representative thereof. A primary control circuit is coupled to receive the sensor signals and, in response thereto, selectively supplies a primary brake activation signal to a brake. The brake, in response to the brake activation signal, selectively supplies a brake force to the energy storage flywheel.

Abstract: In a control apparatus for a motor, an over-current protection circuit detects an abnormality in a motor current forcibly turns off a MOSFET. The over-current protection circuit has a timer function and a time switching function. In the timer operation, the over-current protection circuit stops an abnormality detection signal for an ON time period before producing the signal for an OFF time period when a current flowing through the motor exceeds a predetermined threshold value. The time switching function is for controlling to lengthen the OFF time period to a relatively larger value in comparison with the ON time period.

Abstract: An object is to provide an inverter device capable of realizing exact protection of the winding of a motor. An inverter device for generating a pseudo alternating current by switching a direct current to drive a motor, comprises a controller that executes vector control on the basis of a secondary current applied to the motor. The controller calculates a current density from the secondary current to execute a predetermined protection operation on the basis of the calculated current density. The controller imposes a restriction on the operation frequency of the motor on the basis of the current density.

Abstract: A brushless motor control apparatus detects a phase current flowing in a brushless motor, converts the phase current to a vector current including a d-axis current of a magnetic flux direction component and a q-axis current of a torque direction component orthogonal to the d-axis current, calculates a vector voltage instruction value based on differences between a vector current and a vector current instruction value, calculates a phase voltage instruction value and controls rotation of the brushless motor based on the phase voltage instruction value. The apparatus further calculates electric power produced in the brushless motor and protects the brushless motor based on the magnitude of electric power.

Abstract: A system and method for controlling the voltage output of an alternator is disclosed. The system includes an alternator having a rotor, which has a field winding, a stator having a plurality of phases, a rectifier bridge connected to the plurality of phases, at least one detection circuit connected to each of the plurality of phases, and a controller in communication with the at least one detection circuit and the rectifier bridge. The plurality of phases of the stator are magnetically coupled to the field winding. The rectifier bridge has a plurality of switches for rectifying the alternating current developed in the plurality of stator phases. The at least one detection circuit connected to each of the plurality of phases are used to sense a current reversal in each of the plurality of stator phases. The controller controls the operation of the plurality of switches when the reversal of the current has been sensed by the at least one detection circuit.

Abstract: Inrush currents in the dc intermediate circuit of a motor controller necessitate the incorporation of protection circuits. These circuits usually take the form of a resistor inserted in series with the intermediate circuit, and the resistor is short-circuited after completion of inrush by a switch positioned in parallel with the resistor. To reduce cable-transmitted electrical noise an earthed noise-decoupling capacitor is added to the intermediate circuit, but it also requires protection against inrush currents. To minimise the number of components, a protection circuit is described which combines noise filtration and inrush protection.

Abstract: A method of operating a climate control system includes generating a signal based upon the operation of the compressor, and controlling the compressor in response to the generated signal. A climate control system implementing the method includes a compressor, and module for generating at least one signal based upon the operation of the compressor, and a thermostat for controlling the compressor, the thermostat controlling the compressor in response to signals generated by the module. A system for controlling a compressor in a climate control system implementing the method includes a module that generates signals relating to the operation of the compressor, and a thermostat, responsive to the module, for controlling the compressor. A thermostat for controlling a climate control system having a compressor implementing the method operates the compressor in response to at least one signal representative of the operation of the compressor.

Abstract: A motor control technique is disclosed in which a first algorithm controls interruption of power to a motor in a first current range. A second algorithm controls interruption of power in a second, higher current range. The algorithms may be adapted to specific motor sizes, ratings or classes. The extended range may extend from a transition point (e.g., 6–10 times the FLC of the motor) to an upper limit. The upper limit may be determined based upon a current rating of an instantaneous trip device.

Abstract: Two emergency stop lines are provided. Due to contacts being opened by commands from emergency stop factors and from first and second CPUs, conducting to first and second contactors are stopped. Contacts of the contactors are opened, and power supply to the motor is interrupted, whereby an emergency stop is performed. Further, the first CPU on the first line transmits an abnormality signal to the second CPU when the states of the contacts on the self emergency stop line, detected by digital inputs, are abnormal, and the second CPU opens a contact on the self emergency stop line so as to cause the contactor to be non-excited to thereby stop power supply to the motor.

Abstract: An airflow blockage detection apparatus for a permanent split-capacitor single-phase cooling fan motor measures and compares electrical currents in main and auxiliary windings of the motor to detect airflow blockage. Main and auxiliary current sensors detect AC currents in the main and auxiliary windings, respectively, and a blockage detection circuit forms a difference between the detected currents. An airflow blockage alarm is activated when the current difference exceeds a specified setpoint indicative of abnormally low airflow.

Abstract: In a control apparatus for a motor, an over-current protection circuit detects an abnormality in a motor current forcibly turns off a MOSFET. The over-current protection circuit has a timer function and a time switching function. In the timer operation, the over-current protection circuit stops an abnormality detection signal for an ON time period before producing the signal for an OFF time period when a current flowing through the motor exceeds a predetermined threshold value. The time switching function is for controlling to lengthen the OFF time period to a relatively larger value in comparison with the ON time period.

Abstract: A circuit is provided for limiting the in-rush current of a radio device coupled to a low-power external power source and includes a switch circuit in series between the power source and the radio device, the switch having an “off” state with a high impedance and an “on” state with a low impedance. Also included is a time-delay shorting circuit coupled to the switch circuit, the time-delay shorting circuit having a time constant. In operation, before the time constant elapses, the switch circuit is in the high impedance “off” state for limiting the in-rush current to the radio device and after the time constant elapses, the switch circuit is in the low impedance “on” state so that the radio device is powered by the external power source.

Abstract: A diagnostic system and method for a compressor assembly including a compressor and a motor protector includes logic circuitry associated with the motor protector and operable to analyze a status of the motor protector as a function of time and identify a specific fault cause. The diagnostic system also includes a demand signal sensor and a current sensor, wherein the logic circuitry is associated with the sensors to further enable the diagnostic system to determine a specific fault cause.

Abstract: The present invention achieves technical advantages as a circuit (10) detecting excess current on a servo driver IC and preventing the disruptive damage which can be caused by the excess current. Typically, an isolation (Iso) FET 12 is part of the servo driver IC. The detection circuitry (10) has a sensing FET (14) having only a small silicon area whereby the detection circuit (10) is independent of the Iso FET current (Icc) path, being in parallel rather than in series. The detection circuitry also allows production tests on much smaller current thresholds.

Abstract: A brushless d.c. drive including a synchronous motor, including a multiphase armature winding, a switching device controlled by an electronic controller and connected upstream from the armature winding for commutation of the armature winding, and a device for generating a fail-silent response with simple circuitry measures and without any external components, and which includes a separating apparatus, arrangement or structure in the armature winding to respond in the event of a fault and separate the connections between the winding phases, including at the neutral point.

Abstract: A three-phase motor protector uses two toroids to monitor all three phases of a three-phase motor. Current and phase loss are monitored directly in phases A and B while the phase C current level is determined by analysis of the phase A and B relationship. Current is induced into the phase A and B toroids from the motor supply lines with the resulting wave fed to an input of high-gain inverting amplifiers to provide A and B square waves which are inputted to separate channels of a microprocessor (U3). The square waves are processed by an AND gate providing an output square wave with a 16.66 percent duty cycle for normal operation. Upon loss of phase C the ANDed result is a digital low since the individual waves of phases A and B become an inverse of one another. In order to prevent nuisance tripping an AND output of less than 2 percent duty cycle is treated as a phase loss.

Abstract: A frequency regulator protection circuit for controlling acceleration of electric vehicle comprises a power unit, a display unit, a protection unit, a control unit, a sensor unit, a data processor unit, a trigger unit, a regulator unit, and an output unit. The control unit receives a rotation speed signal from a motor. The sensor unit detects whether there is a current overload and delivers a corresponding overload signal to the data processor unit that consequently outputs a frequency change signal to the trigger unit which, in turn, delivers a first regulation signal to the regulator unit. The output unit further delivers a second regulation signal to the regulator unit, corresponding to different situations of insufficiency of pedal control, brake control, over-speed control, or motor overload. The regulator unit consequently effectuates an adequate cutoff of power supply.

Abstract: A method for generating manipulated variables for the direct-axis and cross voltage, respectively, to represent the flux-forming current ID and torque-forming current IQ in field-oriented control of asynchronous machines, taking into account the stator voltage drop and steady-state internal voltage. The steady-state internal voltage is calculated on the basis of reference variables of the currents.

Abstract: A molded case electric switch housing includes an electric switch control circuit for motor overload and phase loss conditions, a motor contactor control circuit for turning an associated electric motor ON and OFF and a replaceable fuse unit for handling short-circuit type faults. Upon the occurrence of a short circuit within the protected circuit, the fuse rapidly interrupts the short circuit to protect the electric circuit. The fuse is replaced before power is restored to the protected circuit. The arrangement of the electric switch control circuit, motor contactor control circuit and fuse allows single sized switch current-carrying components to be used over a wide range of motor ratings.

Abstract: A method and apparatus are disclosed for preventing damage to an alternator of a genset resulting from high currents within the alternator. The method includes calculating, at a processor, a first quantity related to a current flowing through the alternator during a first time period, and comparing, at the processor, the first quantity with a first threshold. The method further includes calculating, at the processor, a second quantity related to the current flowing through the alternator during at least one of the first time period and a second time period, and comparing, at the processor, the second quantity with a second threshold. The method additionally includes indicating a current overload condition if at least one of the first quantity exceeds the first threshold or the second quantity exceeds the second threshold.

Abstract: The present invention relates to a reverse bias protection structure which comprises a PMOS transistor structure having a drain portion, a gate portion, a source portion and a backgate portion, wherein the gate portion is coupled to a first voltage potential, the source portion is selectively coupleable to a power supply, and the drain portion is selectively coupleable to a circuit needing power to be supplied thereto from the power supply. The reverse bias protection structure further comprises a Schottky diode structure having an anode coupled to the source portion of the PMOS transistor structure, and a cathode coupled to the backgate portion of the PMOS structure. Under forward bias conditions, the PMOS transistor conducts and exhibits a small voltage drop thereacross. Under reverse bias conditions, the PMOS transistor is off and the Schottky structure is reverse biased, thus preventing current through the protection structure.

Abstract: A process and device for determining a run-away condition of a rotation-speed controlled, permanent-excited synchronous motor are described. The process continuously checks, when a rotation speed controller is active and for a predetermined constant rotation speed setpoint, several conditions, either alone or in combination, and generates an error signal if the particular condition or the combination of conditions, when continuously checked, is/are always satisfied during at least a predetermined time interval. These conditions include: determining if the magnitude of a measured deviation in the rotation speed between a measured actual rotation speed value and the predetermined constant rotation speed setpoint increases or reaches a limit value; if the magnitude of a control variable present at the output of a rotation speed controller increases or reaches a limit value; and if the magnitude of a measured acceleration value and/or the magnitude of a torque-producing current increases or reaches a limit value.

Abstract: Graphitic nanofibers, which include tubular fullerenes (commonly called “buckytubes”), nanotubes and fibrils, which are functionalized by chemical substitution, are used as electrodes in electrochemical capacitors. The graphitic nanofiber based electrode increases the performance of the electrochemical capacitors.

Abstract: The invention relates to an apparatus for limiting an electrical current by using a PTC resistor being monitored by a monitor circuit. According to the invention, the monitor circuit issues a signal only after detecting the status of the PTC resistor for a defined time period after a PTC resistance change.

Abstract: According to the present invention, in a water supply apparatus which converts output power of a solar cell with an inverter to drive a motor pump for pumping up water, a DC brushless motor having no sensor for detecting a position of a rotatable shaft is used as a motor for driving the pump.

Abstract: A current detecting apparatus comprises a determining unit which determines whether the electric potential of a first node or a second node is in a predetermined range. When the condition that the electric potential is not in the predetermined range continues longer than the predetermined period of time, the determining signal indicating the damage occurrence is outputted. Accordingly, the damage of the constituting elements can exactly be determined with the relatively simple configuration in a short time.

Abstract: A compressor includes a motor protector which stops the compressor's motor when it senses an out of specification condition. A diagnostic system monitors the status of the motor protector. The diagnostic system includes logic circuitry that diagnoses the type of problem the compressor is having based upon the running times and status of the motor in conjunction with the times and status of the motor protector.

Abstract: A motor-driven curtain assembly includes a drive shaft mounted rotatably in a top rail, a motor for driving rotatably the drive shaft, and a curtain unit coupled to the drive shaft for movement between closed and open positions. A motor-control device includes a driving circuit for enabling rotation of the motor in one of positive and negative directions under the control of a control unit, a current limiting circuit for limiting current flow from an external power source to the driving circuit when the motor is subjected to an increase in load resistance, and an over load detector for generating a control signal that is indicative of the amount of current flowing from the current limiting circuit to the driving circuit and that is provided to the control unit, thereby enabling the control unit to deactivate the driving circuit for stopping operation of the motor when overloading of the motor occurs.

Abstract: An illumination apparatus provides an output with high spatial uniformity of luminance. The illumination apparatus includes a cavity that has reflective surfaces and an output area. At least one light source is disposed in the cavity, with the light source including a point source (such as an LED) and an optical diverter having a flared (e.g., cuspated) reflecting surface. Light from the point source is distributed by the optical diverter towards the reflective surfaces within the cavity. Before exiting the device, light passes through an optical conditioning element that is positioned over the output area of the cavity. The optical conditioning element includes at least a diffuser, such as a translucent film or plastic sheet, and preferably also includes one or more prism sheets such as a brightness-enhancing film.

Abstract: An apparatus for protecting a linear motor having a structure in which permanent magnets and a coil are subjected to relative movement, comprising (a) a means for detecting current flowing through said coil, (b) a multiplying means for calculating the squared value of the detected current every constant time &Dgr;t, (c) a memory means receiving said squared values for successively storing said squared values from the first one to the nth one, the first squared value being eliminated when the (n+1)th squared value is input, and the same operation being repeated subsequently, (d) an adding means for calculating the total of n squared values in said memory means, (e) a means for setting a reference value, which is to be compared with the total of said squared values, (f) a means for comparing the total of said squared values with said reference value for outputting an overload signal when said total has become larger than said reference value, and (g) an overload-preventing means receiving said overload sig

Abstract: A motor driver high current protector includes a voltage source, a current sensor, a comparator, a switch, a delay circuit, and an inhibitor. The current sensor is configured to sense current passing through the motor driver and output a voltage responsive to the sensed current. The comparator has an output and is configured to generate a low voltage at its output while the output of the current sensor exceeds a first reference voltage. The switch has an input, an output, and a base. The base is activated by a low voltage at the output of the comparator to close the switch. Closing the switch provides electrical connection between the input and the output of the switch. The input of the switch is connected to the voltage source. The delay circuit is connected to the output of the switch and is configured to delay the voltage at the output of the switch while the switch is open. The delay circuit may include a resistor and a capacitor each connected to the output of the switch.

Abstract: The relay obtains three-phase current signals from two power line sources thereof, typically two independent feeder lines. The two sets of signals are processed by a single processing means, which independently controls the circuit breakers associated with each feeder line, depending on the values of current obtained.

Abstract: An exemplary embodiment of the invention is a method for detecting a potentially locked axle on a vehicle propelled by an AC motor. The method includes conducting a speed test by estimating axle speed and comparing estimated axle speed to measured vehicle speed. The existence of a potential locked axle condition is determined based on the comparing of estimated axle speed to measured vehicle speed. Additional tests are disclosed for determining a potential locked axle condition and a sensor fault condition.

Abstract: The increasing use of vehicles powered completely or in part by electric motors has created a need for measuring high currents in an inexpensive, reliable and convenient manner for digital motor control. Because the operating voltages of traction motors may be high, it is desirable that the motor current sensors be noncontacting. High-current sensors are commercially available, but tend to be large and costly. According to an aspect of the invention, a noncontacting current sensor having a rated capacity significantly less than the motor (or other) current to be measured is coupled to an electrical conductor for sensing the current in that conductor. The electrical conductor is paralleled by one or more additional similar conductors, so that only a fraction or portion of the current to be measured flows through the conductor associated with the sensor.

Abstract: A system and method for sensing current and/or voltage in a utility system including a plurality of power lines. In particular, a central controller is in communication with and enables a phase-to-phase relationship among current and voltage sensing units for a plurality of different power lines.

Abstract: A motor-driven curtain assembly includes a drive shaft mounted rotatably in a top rail, a motor for driving rotatably the drive shaft, and a curtain unit coupled to the drive shaft for movement between closed and open positions. A motor-control device includes a driving circuit for enabling rotation of the motor in one of positive and negative directions under the control of a control unit, a current limiting circuit for limiting current flow from an external power source to the driving circuit when the motor is subjected to an increase in load resistance, and an over load detector for generating a control signal that is indicative of the amount of current flowing from the current limiting circuit to the driving circuit and that is provided to the control unit, thereby enabling the control unit to deactivate the driving circuit for stopping operation of the motor when overloading of the motor occurs.

Abstract: A motor driver high current protector includes a voltage source, a current sensor, a comparator, a switch, a delay circuit, and an inhibitor. The current sensor is configured to sense current passing through the motor driver and output a voltage responsive to the sensed current. The comparator has an output and is configured to generate a low voltage at its output while the output of the current sensor exceeds a first reference voltage. The switch has an input, an output, and a base. The base is activated by a low voltage at the output of the comparator to close the switch. Closing the switch provides electrical connection between the input and the output of the switch. The input of the switch is connected to the voltage source. The delay circuit is connected to the output of the switch and is configured to delay the voltage at the output of the switch while the switch is open. The delay circuit may include a resistor and a capacitor each connected to the output of the switch.

Abstract: An electrical system, such as a motor control system for a motorized wheelchair, includes a two-part electrical connector which connects a first sub-system to a second sub-system. A reference terminal of one part of the connector is connected to a voltage detecting circuit but is otherwise unconnected: in the event of the connector terminals corroding, a conductive path develops between the reference terminal and one of the other, active terminals and the voltage detecting circuit detects the resulting change in voltage at the reference terminal.

Abstract: An inverter device and a motor driving device are arranged to have a rush preventing circuit for preventing rush current from being flown in a smoothing circuit when the power is turned on. The rush preventing circuit includes a current-limiting means for limiting rush current, a plurality of semiconductor switching elements, a rush preventing circuit driving circuit for driving these semiconductor switching elements, and those semiconductor switching elements being connected in parallel to each other.

Abstract: In the three-terminal motor operator of the present invention, current flowing through half coil causes the rotor to rotate in a first direction, and current flowing through half coil causes the rotor to rotate in a second direction. Rotation of the rotor in the first direction causes the mechanical linkage to move the circuit breaker operating handle towards its “off” or “reset” positions. Rotation of the rotor in the second direction causes the mechanical linkage to move the circuit breaker operating handle towards its “on” position. Pressing the “off” button causes electrical current to flow through the half coil until the circuit is broken by the limit switch. Pressing the “on” button causes electrical current to flow through the half coil until the circuit is broken by the limit switch.

Abstract: A method and system for checking continuity of a motor 104, motor drive, motor relay 110, dc relay 108 and interconnections 122a-c thereof for a power steering system 204. The method and system of the invention produce minimal torque on a motor shaft 426 of the power steering system 204. The position of the motor shaft 426 is located using a Hall effect current sensor 114, a resolver and the like, depending on the type of motor. Thereafter, it is determined which switches 106a-f of an inverter circuitry 100 to switch to produce a minimal torque on the motor shaft 426. The inverter circuit 100 converts dc voltage from a power source 102 to ac voltage required by the motor 104. Thereafter, the switches 106a-f that produce the minimal torque on the motor shaft 426 are switched and current flow is checked to determine the continuity of the circuitry. To produce minimal torque on the motor shaft 426, the complementary pair of switches 106a-f to the first pair is then switched.

Abstract: A device for sensing motor current for over-current protection in an electric power tool. The tool includes an electric motor supplied with electrical power via a live cable and incorporates over-current protection including a tripping circuit with a current sensor associated with the live cable. The device includes a toroid of the sensor and two cable segments connected in parallel to a section of the live cable such that the motor current will be distributed among the cable segments and live cable section in respective proportions. The toroid extends around one cable segment for sensing the respective proportion of the motor current.

Abstract: A safety device for a number of electrical loads that are connected to a supply line between a high-side path and a low-side path. The loads are activatable individually by way of drivers provided in the low-side path. A fuse is provided in the high-side path (2a) and causes, in the event of a defect in at least one driver, a permanent interruption in the high-side path.

Abstract: A combination current sensor and relay has an improved housing. In one aspect, the housing includes light emitting diodes on an upper surface that indicate open circuit and short circuit conditions. In another aspect, the housing includes a securement structure for a circuit board that includes the transformer and switches for device operation, together with aligned openings therein for routing wires to external devices. In another aspect, a multiple position switch is included on the upper surface that indicates multiple modes of operation of the device. In another aspect, the housing may be assembled in multiple parts by affixing a first portion to a support, a circuit board to the first portion, and a second portion to the first portion. In another aspect, the housing is suitable for engagement to alternatively a junction box and a duplex box. In another aspect, the configuration of the upper surface provides usability advantages.

Abstract: A ground fault relay, especially useful to detect motor leakage currents due to insulation failure. The invention operates in two (2) modes. The first mode is a “look-ahead” mode where possible motor circuit insulation failure is detected prior to the electrical motor being turned on, and the second mode is “real time” mode which detects leakage currents after the motor is turned on and during running of the motor. Processing circuitry is disclosed which enables a user to set predetermined values of leakage current to be detected and to trip the relay after comparison of the leakage current and the predetermined value, if the former is larger than the latter. This invention is able to accurately detect extremely small values of ground leakage current without experiencing nuisance tripping due to extraneous noise.

Abstract: In a motor control apparatus, a current control section (1) controls the motor current by judging whether the current value detected by the current detecting unit (4, 7, 14) is of an overcurrent level exceeding an admissible value (Tmax) or a normal level which is equal to or smaller than the admissible value. When the current value detected by the current detecting unit is of an overcurrent level, the current control section restrains the current value to be supplied to the motor irrespective of the external motor torque or speed command, and when the current value detected by the current detecting unit becomes to be the normal level, the current value to be supplied to the motor is restored to an original non-restraint level.

Abstract: A power-feed control apparatus for a vehicle in which electrical loads are arranged in the vehicle includes a power source provided in a vehicle; at least one power semiconductor element, the power semiconductors controlling power-feed to the electrical load; a control unit for controlling the power semiconductor element; an anomaly detection circuit for monitoring operations of the power semiconductor element and determining whether or not an anomaly is occurring in a circuit including the power semiconductor element and the electrical load; and a switching circuit for switching a threshold level between a level for an anomaly detection in a starting period of the load and that in a steady state of the load connected to the power semiconductor element; wherein if an anomaly is detected in the circuit by the anomaly detection circuit, the control unit turns off the power semiconductor so as to interrupt power-feed to the electrical load.

Abstract: If an excess current is detected after the current in the secondary circuit of an induction generator-motor has exceeded a preset value, it is determined that a fault has occurred in the transmission line, provided that the current at the neutral point of a main transformer has exceeded a preset value. In this case, the operation of the induction generator-motor is continued. If no excess current is detected, it is determined that a fault has occurred in the secondary circuit of the induction generator-motor, provided that the current at the neutral point of the main transformer has not exceeded the preset value. In this case, the operation of the induction generator-motor is stopped.

Abstract: A semiconductor switch is installed in a power supply line of a motor, and photocouplers, which constitute a switching control circuit for turning on and off the semiconductor switch, are series-connected between a constant-voltage source and the output ends of a comparator of a starting circuit and a comparator of a trip circuit. An overload at the time of starting the motor is detected by a current transformer, and the semiconductor switch is activated so as to readily cut off the motor driving current.