Abstract: Start capacitor assemblies and methods for operating electric motors are described. In one example, a start capacitor assembly for connection to an electric motor includes a film capacitor and a resistor. The film capacitor has a first terminal and a second terminal.

Abstract: A controller is configured to generate control signals to control a variable frequency drive coupled with a load. A simulator receives the control signals and processes the control signals. The simulator simulates a variable frequency drive and a load by generating feedback signals based on a model and the control signals. The controller receives the feedback signals from the simulator.

Abstract: A thermal protection circuit has two electrical connection terminals for a device to be protected, and a temperature-dependent switch. The switch is provided with a temperature-dependent switching mechanism, two stationary contacts which are connected to the connection terminals, and a current transfer element, which is arranged on the switching mechanism. The current transfer element is moved by the switching mechanism and comprises two counter contacts, which are electrically connected to one another and in temperature-dependent bearing contact with the two stationary contacts. The thermal protection circuit is provided with a controllable semiconductor valve for AC voltage having two current terminals and a control input. Each of the two current terminals is connected to one of the connection terminals, and the control input is electrically connected to the counter contacts at the current transfer element via the switching mechanism at least when the temperature-dependent switch is closed.

Abstract: A low cost motor starter is shown having a PTC resistor 12 serially connected to a triac 14 and a bias resistor in turn adapted to be connected to the start winding of a single phase motor. A reed relay 16 having a sense coil 16a serially connected to the main winding in one preferred embodiment and in parallel with the main and start windings in a second preferred embodiment, is magnetically coupled to reed contacts 16b, 16c. Reed contact 16b is connected to a location intermediate the PTC resistor 12 and the triac 14 while reed contact 16c is connected to the gate of the triac. A gate signal phase shifting network comprising capacitor C1-R2 is also connected to reed contact 16c and the gate.

Abstract: A dual-speed single-phase AC motor, including: a stator, including a stator core, and a coil winding, including a starting winding, a first main winding, and a second main winding, a rotor, and a starting circuit, including a rectifying and voltage-stabilizing circuit, a detecting circuit, a voltage comparison circuit, a first switching circuit, a second switching circuit, and a third switching circuit. The number of poles of the starting winding is the same as that of the first main winding. The number of poles of the first main winding is less than that of the second main winding.

Abstract: Methods and apparatus are provided for a controlling an electric motor that is at least partially disposed within a motor housing. The rotational speed and position of the electric motor are sensed, and a temperature of the electric motor is sensed. The sensor signals are converted to optical signals and are propagated in a fiber optic cable. The electric motor is controlled based, at least in part, on the propagated optical signals.

Abstract: A starting circuit for a single-phase AC motor, the single-phase AC motor comprising a main winding and a starting winding, and the starting circuit comprising a detecting circuit, a rectifying circuit, a triggering circuit, and a switch, wherein the detecting circuit is connected in series with the main winding, the switch is connected in series with the starting winding, the detecting circuit transfers current parameters of the main winding into detecting signals, the rectifying circuit processes the detecting signals and transmits the detecting signals to the triggering circuit, the triggering circuit controls the switch according to the detecting signals whereby controlling power-on and power-off of the starting winding, and the triggering circuit is a hysteresis comparing circuit.

Abstract: An inductive contactless starter for single-phase AC motor, comprising a current inductor and a triac; wherein, one terminal of secondary coil of said current inductor is connected to the gate electrode of said triac, the other terminal is both connected to the first electrode of said triac and the terminal of secondary winding of the motor, and the two terminals of primary coil of said current inductor are connected to the motor and the power supply. By sampling relevant current signals with said current inductor, the invention can control heat loss of the current sampling system effectively down to milliwatt level (i.e., the starter is a “zero power loss”starter for single-phase AC motors), and thereby improve energy efficiency greatly; in addition, the invention has a simple circuit and fewer components and is reliable, improving reliability of the electric starter system while delivering electric starting function.

Abstract: The method and circuit for controlling a sensorless single-phase BLDCM having a stator with a winding are proposed. The provided controlling circuit includes a power supply circuit, an inverter coupled to the winding and the power supply circuit, a BEMF detecting circuit coupled to the winding and the inverter and measuring a BEMF of the winding, and a controller coupled to the power supply circuit, the inverter and the BEMF detecting circuit and analyzing a status of the BEMF to control the BLDCM accordingly. The provided method is based on the motor winding time-sharing theory, and the controller controls the inverter to make the winding used as a driving element with loading current when the absolute value of the BEMF is relatively large and as a sensing element when the absolute value of the BEMF is relatively small.

Abstract: A method and system for estimating a parameter of an electric machine, including a controller and a switching device, the controller executes a parameter estimation process, which is responsive to at least one of: a current value and a torque command and the resultant of the parameter estimation process representing an estimated parameter of the electric machine. The parameter estimation includes a method for estimating a temperature of the electric machine comprising: a temperature sensor operatively connected to and transmitting a temperature signal corresponding to a measured temperature to a controller, which executes a temperature estimation process responsive to a temperature signal from a temperature sensor.

Abstract: A motor starter for use with a motor (20) having a main winding (M) and a start winding (S). The starter has a PTC thermistor (30) connected in series with the start winding (S). A triac (40) is connected between PTC thermistor (30) and a power source line. A control circuit (50) is connected to the power source line for providing a voltage for a gate terminal (G) of triac (40) and an overload relay (60) is connected between the power source (10) and the motor (20). The control circuit (50) preferably includes a current detecting circuit (52) for detecting the inrush current and a voltage generating circuit (54) for generating the voltage in response to the detected inrush current. At the startup of motor (20) the control circuit (50) allows triac (40) to turn on by providing the gate terminal (G) with the voltage based on the inrush current. According to this invention, the power consumption of the start winding S after the startup of the motor (20) can be almost zero thus providing low power consumption.

Abstract: An inverter device capable of smoothly driving an alternating current synchronous motor of large capacity and high-speed rotation is provided. The inverter device includes a power rectification main circuit for converting alternating current power into direct current power and a PWM control inverse transformation main circuit. A transformer raises output terminal of the alternating current power of the inverse transformation main circuit to drive an alternating current synchronous motor. The alternating current motor is started bypassing the transformer and limiting output voltage of the inverse transformation main circuit to a low value through PWM control of the inverse transformation main circuit.

Abstract: The invention prevents the voltage change dv/dt occurring at an inverter from directly igniting a semiconductor braking switch and short-circuiting the inverter during operation. In a dynamic brake circuit which absorbs energy by brake resistor 15 upon igniting semiconductor braking switch 14 and short-circuiting power supply lines of the motor 10 when braking motor 10, which is driven by an inverter part comprised of three-phase AC power supply 1, three-phase bridge rectifier circuit 3, smoothing capacitor 6, and semiconductor switching devices 7, high resistor 20 is disposed between the anode side of the smoothing capacitor 6 and the anode side of the semiconductor braking switch 14, whereby snubber capacitor 17 of snubber circuit 18 connected in parallel to the semiconductor braking switch 14 is charged via this high resistor 20 prior to operation of the inverter part.

Abstract: A motor controller for a motor operated by an AC line voltage includes solid-state switches connectable between an AC line and a motor terminal for controlling application of AC line voltage to the motor. A current sensor senses motor current. A control circuit is connected to the switches and the current sensor for varying relative duration of on time and off time during each cycle of line voltage to control motor voltage. The control circuit determines on time during each cycle of line voltage and compensates sensed motor current responsive to the sensed on time.

Abstract: A starting circuit for a single phase motor having a main winding and a starting winding has a triac in series with the starting winding, and a current sense device in series with the main winding. The current sense device is a NTC resistor or current transformer with a saturable core, and puts out a single to turn on the triac during starting, and removes the triac turn on signal when the main winding energization is sufficiently high to run the motor without the starter winding itself.

Abstract: A starting system for an electric motor having a main coil and an auxiliary coil which are supplied current by an electric current source in which a switch is connected between the electric current source and the auxiliary coil that has an open condition, in which the auxiliary coil remains de-energized by the electric current, and a closed condition for energization of the auxiliary coil with the electric current. An actuating system is positioned relative to the electric motor to receive the magnetic field produced by the motor main coil upon its energization by the electric current for operation of the electric motor that operates to close the switch in response to the magnetic field produced by the current passing through the motor main coil with an intensity above a determined minimum value, and opens the switch when the current through the main coil produces a magnetic field having an intensity of the determined minimum value.

Abstract: A method and apparatus are disclosed for improving the efficiency of operation of AC induction motors. The method and apparatus utilizes a microprocessor to tune a motor control system such that the time interval between the turn-on of a bi-directional switch and the time of sensing the resultant inrush current through the stator is maintained substantially constant as the load is varied.

Abstract: A modified inverter/converter unit electronically commutates a switched reluctance machine to provide multiple voltage levels for engine and aircraft applications. A set of power switching transistors apply an exciting current to windings in the switched reluctance machine to produce power at a first voltage level. Additional voltage levels may be provided by using the turns ratio from one or more transformers and the switching frequency from the power switching transistors. Alternatively, additional voltage levels may be provided by using windings of a plurality of transformers internal to the switched reluctance machine.

Abstract: A doubly-fed reluctance motor (10) has a primary winding set (20) and a secondary winding set (22). A drive control (32) for the motor includes a connection (36) to the primary winding so primary winding current and voltage signals (i.sub.p, V.sub.p) can be developed. A further signal representing the phase relationship (.PHI..sub.p) between the primary winding current and voltage is developed using these signals. A processor module (42) is responsive to these signals to determine the magnitude and phase of a secondary winding current (I.sub.s) of the motor for a predetermined motor operating speed (w.sub.r). The desired current value is as a function of the primary winding current and the phase relationship between the primary winding current and voltage. A switching module (60) operates to regulate the secondary winding currents and opening and closing of switching elements of the module is controlled by an output from the control module.

Abstract: An autotransformer is used to replace the start capacitor in a split phase induction motor. The autotransformer windings are protected by a PTC resistor which also serves to effectively de-energize the auxiliary winding. In a preferred embodiment, efficiency of the motor in the run mode is enhanced by shunting the secondary of the autotransformer with an NTC element. In alternative embodiments a relay coil is placed in series with the auxiliary winding circuit to remove the PTC and the primary of the autotransformer from the circuit when the motor is in the run mode.

Abstract: A starting control circuit is provided for use with a mechanical duty single phase alternating current motor having a start winding and a main or run winding. Both the main and start windings are electrically connected to the alternating current source during the initial starting of the motor. Transducers detect the current phase of both the start and main winding and comparators then compare these current phases together. A comparator generates a pulsed output signal when the phase of the start winding lags the phase of the main winding and this pulsed output signal has a pulse width proportional to the magnitude of the phase lag between the start and main windings. These pulsed output signals are integrated and a electronic switch is activated to disconnect the start winding from the power source whenever the integrated pulsed output signals exceed a predetermined value.

Abstract: A start switch is provided for a single phase AC motor having a start winding and a start capacitor connected in series with the start winding and a main winding connected in parallel with the start winding and start capacitor. The AC motor is connectable with an AC power source in order to supply AC main winding voltage to the main winding and AC start winding voltage to the start winding. The start switch includes conductors connected with the main winding for sensing the AC main winding voltage and conductors connected with the start winding for sensing the AC start winding voltage. Phase sensor circuitry is employed to sense a difference in voltage phase between the start winding voltage and the main winding voltage. Detector circuitry is connected with the phase sensor circuitry to detect when the difference in the voltage phase reaches a threshold.

Abstract: A starting circuit for single phase electric motors including both split-phase and capacitor start motors includes a gate controlled solid state switch serially connected to the start winding of the motor. Rectified reference pulses from a pulse transformer are generated to turn on a first transistor to provide gating current for the solid state switch. Initially, when the motor is energized at zero rpm, the pulses are received at the switch after the start winding current passes through the zero current level to gate the switch to conduct each half cycle and energize the start winding however as the motor speeds up, the pulses are received earlier and earlier relative to the start winding current zero cross over until at a selected speed the pulses are received at the switch prior to the start winding current zero cross over with the result that the switch is no longer gated conductive. When this occurs the voltage across the switch goes high.

Abstract: A starter device for a single phase A.C. motor having a main winding and a starting winding disposed for connection to a single A.C. source. This starter device comprises a semiconductor switching device having a control electrode and a transconductive path, such as, for example a triac. This switching device is connected in series with the starting winding and the single A.C. source to energize or disconnect this starting winding. A magnetic detector is disposed between two adjacent poles of the main winding of the stator of the motor and has its axis of detection extending in the direction of the lines of magnetic flux forced out of the two adjacent saturated poles of the main winding during the initial inrush of current through this main winding upon starting of the motor.

Abstract: This disclosure relates to control apparatus and particularly to a triggered switch connected in a first or controlled circuit and a trigger device connected in a second circuit. AC currents flow through the first and second circuits and there is a changing phase angle between the currents. Further, the current level in the second circuit changes. When the phase angle is greater than a certain value and the current level in the second circuit is above a certain level, the trigger device triggers the switch and energizes the first circuit. At angles below the value and current levels below the certain level, the switch is not triggered. Thus, the changing phase angle may be utilized to control the first circuit. The triggered switch is a thyristor type of device such as a triac, and the trigger device is preferably a reed switch. The control apparatus is particularly useful in controlling the start winding of a single phase AC motor.