Abstract: Methods and systems for detection of zero crossings in a signal are described. For example, true zero crossings in an alternating voltage power source signal can be detected in the presence of noise pulses. The zero crossing detections are performed by establishing a value of a signal status counter, and at a repeating interval if the signal is a logic low value, the value of the signal status counter is decremented if the signal status counter is greater than a first value otherwise a flag is set to enable detection of a zero crossing in the signal. In addition, at the repeating interval, if the signal is a logic high value, the value of the signal status counter is incremented, and if after incrementing the signal status counter is equal to a second value and the flag is set, a zero crossing of the signal is declared.

Abstract: The present invention discloses an arc extinguishing hybrid transfer switch, including a mechanical switch and a first thyristor branch connected in parallel with the first contact branch of the mechanical switch, wherein the first thyristor branch includes a first thyristor, a second thyristor, a first polarized capacitor and a second polarized capacitor, the first thyristor and the first polarized capacitor are connected in series in the same direction, the second thyristor and the second polarized capacitor are connected in series in the same direction, and a branch consisted of the first thyristor and the first polarized capacitor and a branch consisted of the second thyristor and the second polarized capacitor are connected in parallel in reverse direction. The invention further discloses a switching method for the arc extinguishing hybrid transfer switch for implementing an arc extinguishing of a mechanical switch.

Abstract: A method of analyzing the characteristics of a power source includes receiving a power source having at least one phase and sensing voltage signals of each phase of the at least one phase. The method includes detecting a zero crossing event of a selected phase of the at least one phase based on the sensed voltage signals of the selected phase. The method also includes determining, using a processor, voltage information for each phase of the at least one phase based on the corresponding sensed voltage signals. The method further includes outputting a series of pulses via a galvanic isolator in response to the zero crossing event. Respective lengths of some or all of the pulses in the series are based on the corresponding voltage information for each of the at least one phase.

Abstract: A method is provided and may include monitoring a transfer switch and determining an operating condition of the transfer switch based on the monitoring. The method may further include comparing by a processor the operating condition to a predetermined value, and determining a maintenance condition of the transfer switch based on the comparison.

Abstract: Methods and systems for detection of zero crossings in a signal are described. For example, true zero crossings in an alternating voltage power source signal can be detected in the presence of noise pulses. The zero crossing detections are performed by establishing a value of a signal status counter, and at a repeating interval if the signal is a logic low value, the value of the signal status counter is decremented if the signal status counter is greater than a first value otherwise a flag is set to enable detection of a zero crossing in the signal. In addition, at the repeating interval, if the signal is a logic high value, the value of the signal status counter is incremented, and if after incrementing the signal status counter is equal to a second value and the flag is set, a zero crossing of the signal is declared.

Abstract: Methods and systems for detection of zero crossings in a signal are described. For example, true zero crossings in an alternating voltage power source signal can be detected in the presence of noise pulses. The zero crossing detections are performed by establishing a value of a signal status counter, and at a repeating interval if the signal is a logic low value, the value of the signal status counter is decremented if the signal status counter is greater than a first value otherwise a flag is set to enable detection of a zero crossing in the signal. In addition, at the repeating interval, if the signal is a logic high value, the value of the signal status counter is incremented, and if after incrementing the signal status counter is equal to a second value and the flag is set, a zero crossing of the signal is declared.

Abstract: The present invention discloses an arc extinguishing switch, including a mechanical switch and a first electric branch connected in parallel with a first contact branch of the mechanical switch, the first electric branch includes a first controllable unidirectional turn-on subbranch and a second controllable unidirectional turn-on subbranch, the first controllable unidirectional turn-on subbranch and the second controllable unidirectional turn-on subbranch are respectively controlled by two thyristors to be turned on in AC positive and negative periods correspondingly and share a first capacitor connected in series with the two thyristors. The invention further discloses a switching method using the arc extinguishing switch. In the invention, the high power requirement for the thyristor in the arc extinguishing switch and the product cost are lowered, and it is avoided that the mechanical switch is bypassed when the short-circuit failure occurs on the thyristor.

Abstract: The present invention discloses an arc extinguishing hybrid transfer switch, including a mechanical switch and a first thyristor branch connected in parallel with the first contact branch of the mechanical switch, wherein the first thyristor branch includes a first thyristor, a second thyristor, a first polarized capacitor and a second polarized capacitor, the first thyristor and the first polarized capacitor are connected in series in the same direction, the second thyristor and the second polarized capacitor are connected in series in the same direction, and a branch consisted of the first thyristor and the first polarized capacitor and a branch consisted of the second thyristor and the second polarized capacitor are connected in parallel in reverse direction. The invention further discloses a switching method for the arc extinguishing hybrid transfer switch for implementing an arc extinguishing of a mechanical switch.

Abstract: Methods and systems for detection of zero crossings in a signal are described. For example, true zero crossings in an alternating voltage power source signal can be detected in the presence of noise pulses. The zero crossing detections are performed by establishing a value of a signal status counter, and at a repeating interval if the signal is a logic low value, the value of the signal status counter is decremented if the signal status counter is greater than a first value otherwise a flag is set to enable detection of a zero crossing in the signal. In addition, at the repeating interval, if the signal is a logic high value, the value of the signal status counter is incremented, and if after incrementing the signal status counter is equal to a second value and the flag is set, a zero crossing of the signal is declared.

Abstract: An automatic transfer switch includes a solenoid control contacts assembly, an auxiliary contacts assembly, a dual purpose cam attached to a cylindrical shaped weight, and a solenoid actuator. When energized, the solenoid actuator rotates the cylindrical weight and the dual purpose cam actuates both the solenoid control contacts assembly and the auxiliary contacts assembly.

Abstract: A system and method are presented to detect and account for regenerated voltage in a three phase power source failures. The method involves monitoring a power source for phase voltage unbalances to determine the presence of a single phase failure. If the voltage unbalance caused by the single phase failure is restored before a sensing timer expires, a regenerated voltage condition is detected and retransfer to the power source is inhibited. Retransfer to the power source may be delayed by a period determined by a retransfer time value, in order to prevent transfer cycling between the preferred power source and an alternate power source. In addition, retransfer inhibiting may be terminated due to user interaction, power source voltage readings indicating a repair state, or by failure of an alternate source.

Abstract: A method and apparatus for paralleling engine generators. One or more closed transition transfer switches (CTTSes) are coupled to two or more engine generators. A system controller is programmed to operate the one or more CTTSes so that each of the generators provides an emergency power and so that the generators may simultaneously supply emergency power to the power bus.

Abstract: A multi-position apparatus for use with a system operated in at least three distinct positions. The apparatus comprises (i) a position-selection mechanism, (ii) a first link mechanism and a second link mechanism, each link mechanism being operably coupled with the position-selection mechanism, (iii) a first weight-actuated spring mechanism operably coupled with the first link mechanism, (iv) a second weight-actuated spring mechanism operably coupled with the second link mechanism, (vi) a first output-actuating member operably coupled with the first weight-actuated spring mechanism, the first output-actuating member being arranged to operably communicate with the system, and (vii) a second output-actuating member operably coupled with the second weight-actuated spring mechanism. In one example, the system may be an electrical transfer switch having two separate set of electrical contacts.

Abstract: A system and method are presented to detect and account for regenerated voltage in a three phase power source failures. The method involves monitoring a power source for phase voltage unbalances to determine the presence of a single phase failure. If the voltage unbalance caused by the single phase failure is restored before a sensing timer expires, a regenerated voltage condition is detected and retransfer to the power source is inhibited. Retransfer to the power source may be delayed by a period determined by a retransfer time value, in order to prevent transfer cycling between the preferred power source and an alternate power source. In addition, retransfer inhibiting may be terminated due to user interaction, power source voltage readings indicating a repair state, or by failure of an alternate source.

Abstract: A method and apparatus for paralleling engine generators. One or more closed transition transfer switches (CTTSes) are coupled to two or more engine generators. A system controller is programmed to operate the one or more CTTSes so that each of the generators provides an emergency power and so that the generators may simultaneously supply emergency power to the power bus.

Abstract: An automatic transfer switch includes a solenoid control contacts assembly, an auxiliary contacts assembly, a dual purpose cam attached to a cylindrical shaped weight, and a solenoid actuator. When energized, the solenoid actuator rotates the cylindrical weight and the dual purpose cam actuates both the solenoid control contacts assembly and the auxiliary contacts assembly.

Abstract: Method and system for identifying an islanding event in a utility grid. Method includes generating a user defined control signal and applying the user defined control signal to a distributed resource interconnected to the utility grid. The user defined control signal is used to alter at least one operating parameter. In one arrangement, the user definable unintentional islanding control signal includes a first signal defining a first peak disturbance and a second signal defining a second peak disturbance. The user definable unintentional islanding control signal is used to alter at least one operating parameter of said distributed resource.

Abstract: An apparatus and method for detecting battery removal, battery absence, and/or defective battery condition for use with battery charging and testing systems is provided. The apparatus includes a regulator, feedback module, controller, and detector module. The regulator and feedback module supply a regulated charging signal to a battery. The controller interrupts the feedback module so as to cause the regulator to suspend supplying the charging signal to the battery, which in turn, allows the charging signal to discharge for a predetermined period of time. During the predetermined period, the detector module detects whether the charging signal discharges below a predetermined threshold. When the charging signal discharges below the predetermined threshold, the detector module detects one or more conditions that indicate that the battery cannot be charged. These conditions include conditions that indicate that the battery is absent, missing, and/or defective.

Abstract: Method and apparatus for galvanically isolated voltage sensing circuit. A circuit includes a scaling device that provides a scaled signal of an input voltage to a modulator. An oscillator provides a carrier frequency to the modulator, the modulator modulating the scaled signal with the carrier frequency to produce a modulated scaled signal. An isolation transformer is coupled to an output of the modulator. The isolation transformer receives the modulated scaled signal. A demodulator is coupled to an output of the isolation transformer and demodulates the modulated scaled signal to produce an input voltage signal representative of the scaled signal.