MX2008008911A - Receptacle providing sustained excessive voltage protection - Google Patents

Abstract

A receptacle for a power circuit includes a receptacle housing, a line terminal structured to receive a voltage including one of a nominal voltage and a greater excessive voltage, a load terminal, a neutral terminal, a load neutral terminal, separable contacts electrically connected between the line and load terminals, an operating mechanism structured to open and close the separable contacts, and a trip mechanism cooperating with the operating mechanism to trip open the separable contacts. The trip mechanism includes a trip circuit structured to detect a first trip condition associated with the power circuit and to responsively actuate the operating mechanism to trip open the separable contacts. The trip mechanism also includes an overvoltage circuit structured to detect a sustained excessive voltage condition between the at least one neutral terminal and the line or the load terminals and to responsively actuate the operating mechanism to trip open the separable contacts.

Description

RECEPTACLE PROVIDING PROTECTION AGAINST EXCESSIVE SUSTAINED VOLTAGE BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to electrical interrupting apparatuses and, more particularly, to receptacles. BACKGROUND INFORMATION The receptacles are output circuit breakers, which are intended to be installed in a branching circuit output, such as an output box, to provide, for example, load protection against arc faults and / or ground faults. Known receptacles typically include both a reset button and a test button. The reset button is used to activate a reset cycle, which attempts to restore electrical continuity between conductive paths or input and output conductors. While the reset button is depressed, the reset contacts close to complete a test circuit, so that a test cycle is activated. The test button also activates the test cycle, which tests the operation of the circuit interruption mechanism. Receptacles against ground faults and / or known 120 VRMS arc faults are designed to survive the application of 240 VRMS, without firing or without damage. However, if either one or more loads of 120 V ^ g are downstream and / or electrically connected to the receptacle, such loads will most likely be damaged or destroyed by an overvoltage condition of 240 VRMS sustained. Sustained overvoltage conditions can result from a loss of the neutral electrical connection in the installation, load center or upstream circuit breaker. Sustained overvoltage conditions can also occur from certain installation failures. For example, if the neutral is "lost" (eg, due to an electrical problem, due to a neutral "white" wire being disconnected from the energy busbar) in a single-pole power system, two poles or three phases, then the rated line-to-neutral voltage of 120 Vms can be raised to 208 or 240 VRMS, thereby causing the line-to-neutral MOVs in the receptacle to fail (ie, due to a voltage condition). excessive of sufficient duration). Patent US 6,671,150 discloses overvoltage protection in a circuit breaker by employing an analog circuit (eg, a MOV, a sidac, a circuit including a diode, a zener diode and two resistors) to detect a condition of Excessive voltage through a trip coil and in response energize such trip coil.

There is room for improvement in electrical break devices, such as receptacles. SUMMARY OF THE INVENTION These and other needs are met by the present invention, which provides a receptacle that protects a power circuit from a sustained excessive voltage condition. According to one aspect of the invention, a receptacle for an energy circuit comprises: a receptacle housing; a line conductor structured to receive a voltage that includes one of a nominal voltage and an excessive voltage, which is greater than the rated voltage; a charge driver; at least one neutral conductor; at least one set of separable contacts, a set of the at least one set of separable contacts being electrically connected between the line conductor and the load conductor; a structured operating mechanism for opening and closing the at least one set of separable contacts; and a firing mechanism cooperating with the operating mechanism for firing open to the at least one set of separable contacts, the firing mechanism comprising: a first structured circuit for detecting a first firing condition associated with the power circuit and for driving in response to the operating mechanism for firing open to the at least one set of separable contacts, and a second structured circuit for detecting an excessive voltage condition between the at least one neutral conductor and the line conductor or the load conductor and for actuating in response to the operation mechanism for firing open to the at least one set of separable contacts. The line conductor or the load conductor may include the voltage received; the second circuit may comprise a structured voltage sensor for detecting the voltage received from the line conductor or the load conductor and a structured processor for determining whether the detected received voltage is greater than a predetermined value for more than a predetermined time and for responding to the operating mechanism for triggering open to the at least one set of separable contacts, to protect a load downstream of the load conductor from the excessive voltage condition. The voltage received from the line conductor may be an alternating current voltage that includes a plurality of line cycles; the processor may be structured to determine one of a half-cycle integrated peak voltage, an average voltage and an RMS voltage from the sensed received voltage; the predetermined value can be one of an integrated voltage value, an average voltage value and a RMS voltage value; and the predetermined time may be at least the duration of at least one of the line cycles. As another aspect of the invention, a receptacle for an energy circuit comprises: a receptacle housing; a line conductor structured to receive a voltage that includes one of a nominal voltage and an excessive voltage, which is greater than the rated voltage; a charge driver; at least one neutral conductor; at least one set of separable contacts, a set of the at least one set of separable contacts being electrically connected between the line conductor and the load conductor; a structured operating mechanism for opening and closing the at least one set of separable contacts; a first structured circuit for detecting a first trigger condition associated with the power circuit and for driving in response to the operating mechanism for firing open to at least a set of the separable contacts, and a second structured circuit for detecting a condition of sustained excessive voltage between the at least one neutral conductor and the line conductor or the load conductor and in response to actuate the operating mechanism to trip the at least one set of separable contacts. BRIEF DESCRIPTION OF THE DRAWINGS A full understanding of the invention can be obtained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: Figure 1 is a block diagram of a receptacle according to the present invention; Figure 2 is a flow chart of a routine executed by the processor of Figure 1. Description of Preferred Embodiments The present invention is described in association with a receptacle against arc fault / ground fault, although the invention is applicable to a wide range of receptacles. With reference to Figure 1, a receptacle 1 for an energy circuit 4 includes a receptacle housing 6, a line conductor, such as terminal 8, structured to receive a voltage 10 that includes one of a rated voltage and a voltage excessive, which is greater than the rated voltage, a charging terminal 12, and one or more neutral terminals, such as 14 and / or 16. One or two sets of separable contacts 18, 20 are provided. A set 18 of the separable contacts is electrically connected between the line terminal 8 and the charging terminal 12. Another set 20 of the separable contacts can be electrically connected between the neutral terminal 14 and the neutral charging terminal 16. An operating mechanism 22 is structured to open and close the separable contacts 18, 20. A trigger mechanism 24 cooperates with the operating mechanism 22 to open the detachable contacts 18, 20 open. The trigger mechanism 24 includes a first circuit 26 structured to detect a first firing condition associated with the power circuit 4 and for driving in response to the operating mechanism 22 for open firing the separable contacts 18, And a second circuit 28 structured to detect an excessive voltage condition between the neutral charging terminal 16 (or the neutral terminal 14) and the line terminal 8 or the charging terminal 12 and in response to actuate the operating mechanism. 22 for releasing open the detachable contacts 18, 20. Example 1 The example trigger mechanism 24 includes a microcontroller 30, a power supply 32, a signal conditioning circuit 33 and a trigger solenoid 34. The microcontroller 30 includes a analog to digital converter circuit (ADC) 36 and a microprocessor 38 having a firmware routine 40. The ADC circuit 36 includes a plurality of sensors, such as ADC inputs 42, 44, 46, 48 to detect voltages corresponding respectively to the terminal line 8 (line), the charging terminal 12 (charging), a test button 50 (test) and one or more ground terminals 52, 54. The ADC circuit 36 further includes a plurality of sensors, such as inputs ADC 56 and 58, 60, for detecting voltages corresponding to a neutral bypass 62 (current) and the two inputs (sense) from a ground fault current transformer 64, respectively. The microcontroller 30 and the various voltages are referenced to a circuit ground on the neutral load side of the neutral branch 62 at node 66.

The neutral bypass 62 includes a voltage (current) corresponding to current flowing through the separable contacts 20. The ADC input 56 detects that voltage (current) and provides that detected voltage for the step 76 of Figure 2, as will be discussed. The current transformer 64 includes a signal corresponding to the difference between the current flowing through the separable contacts 18 and the charging terminal 12 and current flowing through the separable contacts 20 and the neutral charging terminal 16. The ADC inputs 58, 60 detect this voltage and provide the corresponding value for step 76 of FIG. 2. Example 2 With reference to FIG. 2, the signature routine is shown. After starting at 70, a stopwatch value (eg, hardware, firmware) is set to zero at 72. Next, at 74, the microprocessor 38 reads and suitably processes the various voltages corresponding to the ADC inputs 42 , 44, 46, 48, 56, 58, 60. Then, at 76, an arc fault / earth fault trip logic is executed to process the current value associated with the ADC 56 input and the two detection inputs from the ground fault current transformer 64 at the ADC inputs 58, 60. Under arc fault or earth fault trip conditions, the microprocessor 38 establishes a digital output 77, which provides a TRIP signal to the solenoid of shot 34, for releasing open the separable contacts 18, 20. Next, at 78, it is determined whether the line voltage associated with the ADC input 42 or the charging voltage associated with the ADC input 44 is greater than a predetermined value. If not, then there is an absence of an excessive voltage condition and the execution resumes at 74. Otherwise, there is an excessive voltage condition and, at 80, it is determined whether the timer (eg, hardware, firmware) was initiated. If not, then at 82, the stopwatch starts. Otherwise, or after 82, it is determined whether the chronometer value is greater than a predetermined time. If not, then the execution resumes at 78. On the other hand, if the chronometer value is greater than the predetermined time, then there has been a condition of sustained excessive voltage (eg, the charging voltage with respect to the voltage neutral (circuit_ground)) or adequate time and magnitude. Thus, under such a condition of sustained excessive voltage, at 86, the microprocessor 38 establishes the digital output 77, which provides the TRIP signal to the trigger solenoid 34, to trigger open the separable contacts 18, 20. The microprocessor 38 and the even steps of the firmware routine 78-86, thus, provide the microprocessor-based electronic overvoltage protection circuit 28, while the microprocessor 38 and the step 76 of the firmware routine provide the fault protection circuit -co / faults of electronic ground based on microprocessor 26.

Both step 76 (in the case of an arc fault or ground fault) and step 86 trigger operation mechanism 22 by emitting the trip signal through digital output 77 to trip solenoid 34, to trigger open the separable contacts 18, 20 and protecting a load (not shown) downstream of the load terminal 12 from the condition of sustained excessive voltage. Example 3 The received voltage 10 of the line terminal 8 can be an alternating current voltage that includes a plurality of line cycles. In step 74, the microprocessor routine 40 can be structured to determine one of a half integrated cycle peak voltage, an average voltage and an RMS voltage from the detected received voltage of the ADC input 42. Example 4 In step 78, the predetermined value it can be one of an integrated voltage value, an average voltage value, and a RMS voltage value (e.g., without limitation, about 150 VRMS). In step 84, the predetermined time can be at least the duration of at least one of the line cycles (e.g., without limitation, about 16.67 ms at 60 Hz). Thus, if a sustained excessive voltage above a predetermined threshold for a predetermined time is detected, then the receptacle 2 opens one or both sets of separable contacts 18, 20 to disconnect any connected load or current-down load from the voltage source. excessive. Example 5 The protection circuit 26 can be, for example, one or both of an arc fault protection circuit and a ground fault protection circuit. Non-limiting examples of arc fault detectors are disclosed, for example, in US Patent 5,224,006, with a preferred type described in US Patent 5,691,869, which is therefore incorporated herein by reference. Non-limiting examples of ground fault detectors are disclosed in US Patents 5,293,522; 5,260, 676; 4,081,852; and 3,736,468, which are therefore incorporated by reference herein. Example 6 Although step 78 may employ one or both of the line voltage and the charging voltage, preferably, at least the line voltage is detected to determine a normal, non-excessive voltage condition, or a voltage condition. excessive.

Example 7 As is conventional, the operating mechanism 22 preferably includes a suitable reset mechanism, such as the RESET button 88, structured to mechanically close the separable contacts 18, 20. Example 8 As is conventional, the trigger mechanism 24 of preference includes a suitable test mechanism, such as the TEST 50 button, structured to initiate one or both of an arc fault protection test and a ground fault protection test. If the test signal at the ADC input 46 is active, then suitable signals (not shown) are sent to the control circuit 90 to apply simulated fault signals (not shown) to test the arc fault / ground fault protection. For example, the test button 50 can test the dual function ground fault and arc fault logic 76 as disclosed in US Patent No. 5,982,593, which is therefore incorporated by reference herein. Example 9 Although two sets of separable contacts 18, 20 are shown, the receptacle 2 may include a single set of separable contacts (eg, separable contacts 18 electrically connected between the line and load terminals 8, 12).

Example 10 The receptacle 2 preferably includes a suitable indication circuit 92 structured to indicate different fault conditions. For example, circuit 92 includes a first LED 94 driven by microprocessor output 95 and a second LED 96 driven by microprocessor output 97. Example 11 In addition to example 10, LED 96 is red and structured to indicate at least one of the excessive voltage condition, the arc fault trip condition and the ground fault trip condition, while the LED 94 is green, and when illuminated, indicates a normal receptacle condition without failure. EXAMPLE 12 In addition to example 10, the LED 96, when illuminated, is structured to indicate the arc fault trip condition and the LED 94, when illuminated, is structured to indicate the ground fault trip condition. Example 13 In addition to example 12, one of the LEDs 94, 96, such as 94, may be structured to indicate the excessive voltage condition by flashing a corresponding pattern, and to indicate one of the arc fault trip condition and the condition Triggering ground fault by being lit solidly. Example 14 In addition to example 12, both of the LEDs 94, 96, when illuminated, can be structured to indicate the excessive voltage condition. Example 15 The power supply 32 is preferably energized from both of (e.g., through one or more auction diodes (not shown)) of the charging terminal 12 and the line terminal 8, so as to protect downstream loads under normal and reverse feed conditions. Alternatively, the power supply 32 can be energized from at least one of the terminals 8, 12. Example 16 As shown in Figure 1, a MOV 100 can be arranged between the charging terminal 12 and the neutral charging terminal 16, to provide transient voltage protection. The advantageously disclosed receptacle 2 provides electronic overvoltage protection by detecting line and / or load voltages with respect to a suitable circuit ground reference (e.g., a neutral voltage). If the sustained detected voltage (e.g., integrated average cycle peak, average, RMS) is above a predetermined value (e.g., without limitation, 150 VRMS) for a predetermined time (e.g., without limitation, a line cycle, a plurality of cycles, a suitable time), then the downstream loads are disconnected from the source of the overvoltage. Although specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are intended to be illustrative only and not limiting as to the scope of the invention to which the full scope of the appended claims and any and all equivalents thereof will be given.

Claims (20)

1. CLAIMS 1. A receptacle (2) for an energy circuit (4), said receptacle comprising: a receptacle housing (6); a line conductor (8) structured to receive a voltage (10) including one of a nominal voltage and an excessive voltage, which is greater than said nominal voltage; a charge conductor (12); at least one neutral conductor (14, 16); at least one set of separable contacts (18, 20), a set (18) of said at least one set of separable contacts being electrically connected between said line conductor and said load conductor; an operating mechanism (22) structured to open and close said at least one set of separable contacts; and a firing mechanism (24) cooperating with said operating mechanism for open firing said at least one set of separable contacts, said firing mechanism comprising: a first circuit (38, 26, 56, 62) structured to detect a first trigger condition associated with said power circuit and in response to operating said operating mechanism for open firing said at least one set of separable contacts, and a second circuit (38, 28, 42, 44) structured to detect a condition of excessive voltage between said at least one neutral conductor and said line conductor or said load conductor and in response to actuate said operation mechanism to open-fire said at least one set of separable contacts. The receptacle (2) of claim 1, wherein said line conductor or said charge conductor includes said received voltage; wherein said second circuit comprises a voltage sensor (42, 44) structured to detect the received voltage of said line conductor or said load conductor and a processor (38) structured to determine if said received received voltage is greater than a predetermined value for more than a predetermined time and in response to actuate said operating mechanism for open firing said at least one set of separable contacts, to protect a load downstream of said load conductor from said excessive voltage condition. The receptacle (2) of claim 2, wherein the voltage received from said alternating current voltage line conductor includes a plurality of line cycles; wherein said processor is structured to determine one of a half-cycle integrated peak voltage, an average voltage and an RMS voltage from said sensed received voltage; wherein said predetermined value is one of an integrated voltage value, an average voltage value and a RMS voltage value; and wherein said predetermined time is at least the duration of at least one of said line cycles. The receptacle (2) of claim 1, wherein said second circuit comprises a voltage sensor (44) structured to detect a voltage between said load conductor and said at least one neutral conductor for detecting said excessive voltage condition. The receptacle (2) of claim 1, wherein said second circuit comprises a voltage sensor (42) structured to sense a voltage between said line conductor and said at least one neutral conductor and a processor (38) structured to compare said detected voltage to a predetermined value to detect an absence of said excessive voltage condition. The receptacle (2) of claim 1, wherein said first circuit is an arc fault protection circuit (26). The receptacle (2) of claim 6, wherein said second circuit comprises a voltage sensor (56) and a branch (62) electrically connected in series with said one set of said at least one set of separable contacts, said derivation including a voltage corresponding to current flowing through said one set of said at least one set of separable contactssaid voltage sensor being structured to detect said voltage corresponding to current flowing through said one set of said at least one set of separable contacts and providing said detected voltage to said arc fault protection circuit. The receptacle (2) of claim 1, wherein said first circuit is a ground fault protection circuit (26). The receptacle (2) of claim 8, wherein said second circuit comprises a voltage sensor (58, 60) and a current transformer (64) operatively associated with said one set of said at least one set of separable contacts. said current transformer including a signal corresponding to a difference between current flowing through said set of said at least one set of separable contacts and current flowing through said at least one neutral conductor, said sensor voltage being structured to detect the signal of said current transformer and providing said detected signal to said ground fault protection circuit. The receptacle (2) of claim 1, wherein said operating mechanism comprises a reset mechanism (88) structured to mechanically close said at least one set of separable contacts. The receptacle (2) of claim 1, wherein said first circuit comprises at least one of an arc fault protection circuit (26) and a ground fault protection circuit (26). The receptacle (2) of claim 1, wherein said at least one set of separable contacts includes a first set of separable contacts (18) and a second set of separable contacts (20); wherein said at least one neutral conductor includes a neutral conductor (14) and a neutral charge conductor (16); wherein said first set of separable contacts is electrically connected between said line conductor and said load conductor; and wherein said second set of separable contacts is electrically connected between said neutral conductor and said neutral load conductor. The receptacle (2) of claim 1, wherein said first circuit comprises an arc fault trip circuit (26) structured to trip open said at least one set of separable contacts in response to a fault trip condition of arc, and a ground fault trip circuit (26) structured to trip open said at least one set of separable contacts in response to a ground fault trip condition. The receptacle (2) of claim 13, wherein said triggering mechanism further comprises at least one indicator (92) structured to indicate at least one of said excessive voltage condition, said arc fault tripping condition and said ground fault trip condition. The receptacle (2) of claim 14, wherein said at least one indicator includes a first indicator (96) structured to indicate said arc fault tripping condition and a second indicator (94) structured to indicate said arc fault condition. ground fault trip. The receptacle (2) of claim 14, wherein said at least one indicator is a single indicator (94) structured to indicate said excessive voltage condition by blinking a pattern, and to indicate at least one of said condition of arc fault trip and said ground fault trip condition by solidly illuminating. The receptacle (2) of claim 1, wherein said trigger mechanism further comprises an energized supply (32) energized from at least one of said line conductor and said load conductor. 18. A receptacle (2) for an energy circuit (4), said receptacle comprising: a receptacle housing (6); a line conductor (8) structured to receive a voltage (10) including one of a nominal voltage and an excessive voltage, which is greater than said nominal voltage; a charge conductor (12); at least one neutral conductor (14, 16); at least one set of separable contacts (18, 20), a set (18) of said at least one set of separable contacts being electrically connected between said line conductor and said load conductor; an operating mechanism (22) structured to open and close said at least one set of separable contacts; a first circuit (38, 26, 56, 62) structured to detect a first trip condition associated with said power circuit and in response to actuate said operation mechanism to open trip said at least one set of separable contacts, and a second circuit (38, 28, 42, 44) structured to detect a condition of excessive voltage between said at least one neutral conductor and said line conductor or said load conductor and in response to actuate said operation mechanism to trigger open said at least one set of separable contacts. The receptacle (2) of claim 18, wherein at least one of said line conductor and said load conductor includes said received voltage; wherein said second circuit comprises a voltage sensor (42, 44) structured to detect said received voltage and a processor (38) structured to determine whether said detected received voltage is greater than a predetermined value for more than a predetermined time and to act on said operating mechanism for open firing said at least one set of separable contacts, to protect a load downstream of said load conductor from said sustained excessive voltage condition. The receptacle (2) of claim 19, wherein the voltage received from said line conductor is an alternating current voltage that includes a plurality of line cycles; wherein said processor is structured to automatically determine one of a half cycle integrated peak voltage, an average voltage and an RMS voltage from said received voltage; wherein said predetermined value is one of an integrated voltage value, an average voltage value and a RMS voltage value; and wherein said predetermined time is at least the duration of at least one of said line cycles.