NZ524371A - Circuit breaker having a primary contact, wherein the test and activation circuits are disconnected from mains when primary contact is open - Google Patents
Circuit breaker having a primary contact, wherein the test and activation circuits are disconnected from mains when primary contact is openInfo
- Publication number
- NZ524371A NZ524371A NZ52437103A NZ52437103A NZ524371A NZ 524371 A NZ524371 A NZ 524371A NZ 52437103 A NZ52437103 A NZ 52437103A NZ 52437103 A NZ52437103 A NZ 52437103A NZ 524371 A NZ524371 A NZ 524371A
- Authority
- NZ
- New Zealand
- Prior art keywords
- circuit
- contact
- primary contact
- primary
- test
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
- H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
- H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
- H02H3/334—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control
- H02H3/335—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial unbalance for other protection or monitoring reasons or remote control the main function being self testing of the device
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
- H01H83/02—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by earth fault currents
- H01H83/04—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by earth fault currents with testing means for indicating the ability of the switch or relay to function properly
- H01H2083/045—Auxiliary switch opening testing circuit in synchronism with the main circuit
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
- H01H71/10—Operating or release mechanisms
- H01H71/12—Automatic release mechanisms with or without manual release
- H01H71/46—Automatic release mechanisms with or without manual release having means for operating auxiliary contacts additional to the main contacts
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
- H01H83/02—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by earth fault currents
- H01H83/04—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by earth fault currents with testing means for indicating the ability of the switch or relay to function properly
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Breakers (AREA)
Abstract
A circuit breaker (10) for use in an electrical circuit having active (16) and neutral (18) conductors, comprises: a sensing circuit (24) arranged to sense existence of a fault condition in the electrical circuit; a test circuit (56,58) for generating a pseudo fault condition in the electrical circuit; a primary contact (20,22) arranged to pass current, in use, between a mains supply (12) and a load (14) when the primary contact is in a closed position; an activation circuit (26) for moving the primary contact (20,22) to an open position in response to signal from the sensing circuit indicative of a fault condition or a pseudo fault condition; an auxiliary contact (52) located in circuit with the activation circuit and selectively connectable to the test circuit, the auxiliary contact being in contact with the primary contact when the at least one primary contact is in a closed position and not being in contact with the primary contact when the primary contact is in an open position; and the arrangement being such that both the test circuit and the activation circuit are disconnected from the mains supply when the primary contact is in an open position.
Description
5243 7 1
Intellectual Property
OffiCH o* to.Z.
2 1 FEB 2003 RECEIVED
PATENTS FORM NO. 5
Fee No. 4: $250.00
PATENTS ACT 1953 COMPLETE SPECIFICATION
CIRCUIT BREAKER
I/WE H.P.M. Industries Pty Ltd, an Australian company of Unit 4, 44-48 O'Dea Avenue, Waterloo, NSW 2017, Australia hereby declare the invention, for which I/We pray that a patent may be granted to me/us, and the method by which it is to be performed to be particularly described in and by the following statement:
1
To be followed by Page 1A
James & Wells Ref: 121808/0 RJ
_ la -CIRCUIT BREAKER
Field of the Invention •
The present invention relates to a circuit breaker for use in an electrical circuit having active and neutral conductors and, in particular, to a residual current-type circuit breaker for detecting the existence of a current fault and for disconnecting a load from a mains supply when such a current fault is detected.
Background of the Invention
It is known to include circuit breakers in electrical circuits so as to provide protection against electrocution and fire caused by electrical faults.
One such circuit breaker is a residual cunrent device (ROD) or residual current circuit breaker (RCCB) which monitors the current flowing in active and neutral wires of an electrical circuit Under normal circumstances, the current flowing in the active and neutral wires is equal. However, when an earth fault occurs some current from the active or neutral wire is diverted to earth and a current differential occurs between the active and neutral wires. When a current differential is detected, primary contacts are opened so as to disconnect a load from the mains supply.
In voltage dependent-type circuit breakers, a solenoid is generally used to effect opening of the primary contacts. However, in order to prevent damage 1o the solenoid on occurrence of a fault, the circuit breaker must include a mechanism for disconnecting the solenoid from the mains supply. Alternatively, in the absence of such a mechanism the mains supply must always be connected to a particular side of the circuit breaker,
Generally, such circuit breakers also include a test circuit to generate a pseudo electrical fault and thereby cause the primary contacts to open so that the efficacy of the circuit breaker can be periodically verified. However, such test circuits generally include a test resistor which can burn out if the test circuit is not also disconnected from the mains f:\jncl»on\.kM:D\»peel\CI*£tfr: BWWW - HI m73S«.acc
supply when the primary contacts are opened.
Summary of the Invention
In accordance with an aspect of die present invention, there is providiid a circuit breaker for use in an electrical circuit having active and neutral conductors, the circuit breaker including:
a sensing circuit arranged to sense existence of a fault condition in the electrical circuit;
a test circuit for generating a pseudo fault condition in the electrical circuit;
a primary contact arranged to pass current, in use, between a mains supply and a load when the primary contact is in a closed position,
an activation circuit for moving the primary contact to an open position in response to a signal from the sensing circuit indicative of a fault condition or a pseudo 15 fault condition;
an auxiliary contact located in circuit with the activation circuit and selectively collectable to the test circuit, the auxiliary contact being in contact with the primary contact when the at least one primary contact is in a closed position, and not being in contact with the primary contact when the primary contact is in an open position; and 20 the arrangement being such that both the test circuit and the activation circuit are disconnected from the mains supply when the primary contact is in an open position.
Preferably, the primary contact includes a first contact portion arranged to connect a load to a mains supply during use when the primary contact is in a closed position and a 25 second contact portion arranged to connect the auxiliary contact to the mains supply when the primary contact is in a closed position.
Preferably, the auxiliary contact is cormectable to the test circuit using a test switch arranged to bring the auxiliary contact into connection with the test circuit when the test 30 switch is activated. Preferably, die tost switch is a press button.
In one arrangement, the auxiliary contact is an integral member, preferably a leaf spring r:\]nftJjau\lceep\5peci\CIJlCUIY BIENCEft - ME FPl7394.doc
or a coil spring.
Preferably, a first primary contact is provided for passing current between an active wire of the mains supply and a load when the first primary contact is in a closed position, and 5 a second primary contact is provided for passing current between a neutral wire of a mains supply and a load when die second primary contact is in a closcd position.
Preferably, die sensing circuit is arranged to sense existence of a current differential between active and neutral wires of the mains supply.
Preferably, the circuit breaker is a residual current circuit breaker (RCCB). Brief Description of the Drawings
The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which;
Figure 1 is a diagrammatic representation of a circuit breaker in accordance with an embodiment of the present invention shown, in use, in relation to a load;
Figure 2 is a diagrammatic representation of a circuit breaker in accordance with an alternative embodiment of the present invention;
Figure 3 is a diagrammatic perspective view of a contact housing of the circuit breaker 25 shown in Figure 1; and
Figure 4 is a diagrammatic cross sectional view of the contact housing shown in Figure 3.
Description of a Preferred Embodiment of the Present Invention
Referring to Figure 1 of die drawings, there is shown a circuit breaker 10 for connecting
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_ 4 -
a mains supply 12 to a load 14 and for disconnecting the mains supply 12 from the load 14 on the occurrence of an electrical fault Power is supplied from the mains supply 12 through active and neutral wires 16,18 respectively.
Hie embodiment shown in Figure 1 is a residual current circuit breaker (RCCB) and, as such, the circuit breaker 10 detects the existence of a current differential between the active and neutral wires 16,18 and thereby the existence of a fault current between one of the active and neutral wires 16,18 and earth,
The circuit breaker 10 in this example includes primary contacts in die form of an active contact 20 for connecting the active wire 16 to or disconnecting the active wire 16 from the load 14, and a neutral contact 22 for connecting the neutral wire 18 to and disconnecting the neutral wire 18 from the load 14.
The active contact 20 includes a primary switch portion 23 and an auxiliary switch portion 25.
The circuit breaker 10 also includes a sensing circuit 24 for sensing a current differential between the active and neutral wires 16,18 and an activating circuit 26 for receiving a signal from the sensing circuit 24 and moving the primary contacts 20, 22 to an open position when a signal indicative of a current differential is received from the sensing circuit 24.
The sensing circuit 24 includes a toxoid 28 on which there is disposed a first winding 25 30, an absorption circuit 31, an amplifier 32 for amplifying signals generated by the first winding 30, and a filter 34 for removing spikes.
The activating circuit 26 includes a solenoid 36 associated with the primary contacts 20, 22 and arranged to move the primary contacts 20, 22 to an open position when the 30 solenoid 36 is energised. The activating circuit 26 also includes a full wave bridge rectifier having first, second, third and fourth diodes 38, 40, 42 and 44 respectively, a first resistor 46 and capacitor 48 in series for smoothing the output of die bridge
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rectifier, and a switching device, in this example in the form of an SCR.
The circuit breaker 10 also includes an auxiliary contact 52, in this example in the form of a generally U-shaped leaf spring, the auxiliary contact 52 including an activating 5 circuit contact 54 and a test circuit contact 56. A portion of the auxiliary contact 52 between the activating circuit contact 54 and the test circuit contact 56 is connected in circuit with the bridge rectifier of die activating circuit 26. The activating circuit contact 54 is arranged to contact the auxiliary switch portion 25 of die active contact 20 when the active contact 20 is in a closed position. Similarly, the test circuit contact 56, 10 being integral with the activating circuit contact 54, makes electrical contact with the auxiliary switch portion 25 of the active contact 20 when the active contact 20 is in a closed position. The auxiliary contact 52 is biased towards a position wherein the activating circuit contact 54 touches die auxiliary switch portion 25 when the active contact 20 is in a closed position.
Provided on the test circuit contact 56 is a test button 58 which, when pressed, serves to connect the auxiliary contact 52 to a fixed contact 59 in circuit through a second resistor 62 with a second winding 60 disposed on the toroid 28,
2 0 The test button 58, the fixed contact 59, the second resistor 62, the second winding 60, the rectifier and the solenoid 36 together form a test circuit for generating a pseudo fault condition used to verify'that the circuit breaker 10 is operating correctly.
In operation, primary contacts 20, 22 are initially in a closed position and current is 25 supplied from the mains supply 12 through die active and neutral wires 16, 18 to the load 14. Also, since the primary contacts are in a closed position, the activating circuit contact 54 and thereby die auxiliary contact 52 is connected to the active wire 16.
With the primary contacts 20, 22 in this position, current will flow through the 30 activating circuit contact 54, the rectifier, the first resistor 46, the capacitor 48 and the solenoid 36. However, the current is not enough to sufficiently energise the solenoid 36 to cause the primary contacts 20,22 to close.
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In the absence of a current leakage to earth, the current flowing through the active and neutral wires 16,18 will be equal and no current differential will be sensed by the first winding 30. As a result, a gating signal is not generated by the sensing circuit 24, the 5 SCR is in a non-conducting state and no current flows through the SCR 50.
When a fault occurs and an associated current flows from either the active wire 16 or the neutral wire 18 to earth, a current differential is sensed by the first winding 30, amplified and filtered by the amplifier and filter 32,34, and a gating signal is supplied 10 to the SCR 50 to switch the SCR 50 to a conducting state. When this occurs, a current flows through the activating circuit contact 54, the rectifier, the SCR 50 and the solenoid 36. This current is sufficient to energise the solenoid 36 to cause the primary contacts 20,22 to open to thereby disconnect the supply 12 from the load 14. Moving the primary contacts 20,22 to the open position also opens the contact between 15 the activating circuit contact 54 and the auxiliary switch portion 25, thereby disconnecting power to the SCR 50 and solenoid 36 so as to reset the activating circuit 26.
In order to test operation of the circuit breaker 10 when the primary contacts 20,22 are 20 in a closed position, a user depresses the test button 58 so as to cause current to flow through the activating circuit contact 54, the test circuit contact 56, the second resistor 62, the second winding 60, the rectifier and the solenoid 36. Although the magnitude of this current is insufficient to cause the primary contacts 20,22 to close, the effect of the current flowing through the second winding 60 is to generate a current flowing through 25 the second winding 60 which is detected by tike first winding 30. This causes the sensing circuit 24 to generate a gating signal to switch the SCR 50 to a conducting state and thereby cause the primary contacts 20,22 to open. Moving the active contact 20 to an open position also causes the contact between the activating circuit contact 54 and the auxiliary switch portion 25 to open to thereby disconnect power to the second 3 0 resistor and second winding 60 of the test circuit.
It will be understood that by providing an auxiliary contact 52 for supplying power to
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both the activating circuit 26 and the test circuit, which auxiliary contact 52 breaks contact with the active contact 20 when the active contact 20 moves to an open position, a simple and cost effective arrangement is provided for disconnecting power from both the activating circuit 26 and the test circuit
Although the above embodiments have been described in relation to circuitry which is connected directly to the mains supply side, it will be understood that the locations of the load and mains supply are interchangeable. This is because at least one of the active and neutral wires 16,18 is isolated from the circuitry of the circuit breaker 10 when the 10 primary contacts 20,22 are in an open position irrespective of the location of the mains supply.
An alternative embodiment of a circuit breaker 64 is shown in Figure 2. Like features are indicated with like reference numerals. The circuit breaker 64 is the same as the 15 circuit breaker 10 shown in Figure 1, except that the auxiliary contact 52 includes a coil spring, a first side of the coil spring being in contact with an activating circuit contact 54 and a second side of the coil spring forming the test circuit contact 56.
Although the above embodiments have been described in relation to a circuit breaker 20 having an auxiliary contact associated with the active wire 16, it will be understood that an auxiliary contact could instead be associated with the neutral wire 18.
A contact housing 68 fin: use with the above described embodiment shown in Figure 1 is shown in Figures 3 and 4. In the contact housing is disposed primary contacts, only 25 active contact 20 being shown for clarity, an auxiliary contact 52 in the form of a generally U-shaped leaf spring having an activating circuit contact 54 at one end of the U and a test circuit contact 56 at the other end of the U. Hie test circuit contact 56 is associated with a test button (not shown) which, when pressed, acts to urge the test circuit contact 56 into contact with the fixed contact 59 of the test circuit Operatively 30 associated with the active contact 20 is a cam 70 arranged to move outwardly of a housing portion 72 when the primary contacts move to an open position so as to disconnect the active contact 20 from the auxiliary contact 52.
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It will be understood that instead of a leaf spring, the auxiliary contact 52 may include a coil spring as shown in Figure 2 for maintaining contact between die actuating circuit. contact 54 and the cam 66 when the primary contacts are in a closed position.
It will be appreciated that although, the above embodimexits have been described in relation to a 2 pole circuit arrangement including active and neutral wires, the invention is equally applicable to other arrangements such as 4 pole circuit arrangements.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.
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Claims (8)
1. A circuit breaker for use in an electrical circuit having ivctive and neutral conductors, the circuit breaker including: 5 a sensing circuit arranged to sense existence of a fault condition in the electrical circuit; a test circuit for generating a pseudo fault condition in die electrical circuit; a primary contact arranged to pass current, in use,-between a mains supply and a load when the primary contact is in a closed position, 10 an activation circuit for moving (he primary contact to an open position in response to a signal from the sensing circuit indicative of a fault condition or a pseudo fault condition; an auxiliary contact located in circuit with the activation circuit and selectively coiraectable to the test circuit, the auxiliary contact being in contact with the primary 15 contact when the at least one primary contact is in a closed position, and not being in contact with the primary contact when the primary contact is in an open position; and the arrangement being such that both the test circuit and the activation circuit are disconnected from the mains supply when the primary contact is in an open position. 20
2. A circuit breaker as claimed in claim 1, wherein the primary contact includes a first contact portion arranged to connect a load to a mans supply during use when the primary contact is in a closed position and a second contact portion arranged to connect the auxiliary contact to the mains supply when the primary contact is in a closed position. 25
3. A circuit breaker as claimed in claim 1 or claim 2, wherein an auxiliary contact is connectable to the test circuit using a test switch arranged to bring the auxiliary contact into connection with the test circuit when the test switch is acl ivated. 30
4. A circuit breaker as claimed in claim 3, wherein the test switch is a press button.
S. A circuit breaker as claimed in any one of the preceding claims, wherein the rt\3n«l*on\ica«pVspccl\cx]un!X1 BXEftKEft - MZ 1*17394.doc - 10 - auxiliary contact is a leaf spring or a coil spring.
6. A circuit breaker as claimed in any one of the preceding claims, wherein the circuit breaker includes a first primary contact for passing current between an active 5 wire of the mains supply and a load when the first primary contact is in a closed position, and a second primary contact for passing current between a neutral wire of a mains supply and a load when the second primary contact is in a closed position.
7. A circuit breaker as claimed in any one of die preceding claims, wherein tile 10 sensing circuit is arranged to sense existence of a current differential between active and neutral wires of the mains supply.
8. A circuit breaker substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings. 15 H.P.M. Industries Pty Ltd By their Attorneys END OF CLAIMS F:\jnelEaaMttepVapedNCIKCOlr BREAKER « HZ FP173M.4o« - 11 -ABSTRACT A circuit breaker (10) is disclosed for use in an electrical circuit having active (16) and neutral (18) conductors. Tlie circuit breaker (10) includes a sensing circuit (24) 5 arranged to sense existence of a fault condition in the electrical circuit and a test circuit (58, 59,62, 60,36) for generating a pseudo fault condition in the electrical circuit The circuit breaker (10) also includes a primary contact (20) arranged to pass current, in use, between a mains supply (12) and a load (14) when the primary contact (20) is in a closed position, an activation circuit (26) for moving the primary contact (20) to an open 10 position in response to a signal from the sensing circuit (24) or the test circuit indicative of a fault condition or a pseudo fault condition, and an auxiliary contact (52) located in circuit with the activation circuit (26) and selectively connectable to the test circuit, die auxiliary contact (52) being in contact with the primaiy contact (20) when the at least one primary contact (20) is in a closed position, and not being in contact with the 15 primaiy contact (20) when the primary contact is in an open position. The arrangement is such that both the test circuit and the activation circuit (26) are disconnected from the mains supply (12) when the primacy contact (20) is in an open position. F:\Jnal=im\B:epS=pcct\CIBeuil BREAKER - HZ ni7394.doc
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPS1041A AUPS104102A0 (en) | 2002-03-12 | 2002-03-12 | Circuit breaker |
| AUPS1085A AUPS108502A0 (en) | 2002-03-14 | 2002-03-14 | Circuit breaker |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NZ524371A true NZ524371A (en) | 2004-03-26 |
Family
ID=25646881
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NZ52437103A NZ524371A (en) | 2002-03-12 | 2003-02-21 | Circuit breaker having a primary contact, wherein the test and activation circuits are disconnected from mains when primary contact is open |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2386773A (en) |
| NZ (1) | NZ524371A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8563882B2 (en) * | 2010-10-12 | 2013-10-22 | Siemens Industry, Inc. | Electronic circuit breaker having a locking and unlocking mechanism and methods of operating same |
| EP2926359A1 (en) * | 2012-11-29 | 2015-10-07 | Eaton Industries (Austria) GmbH | Switching device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2301498B (en) * | 1992-07-22 | 1997-01-29 | Technology Res Corp | Ground fault circuit interrupter |
| GB9416569D0 (en) * | 1994-08-16 | 1994-10-12 | Crabtree Electrical Ind Ltd | Residual current devices |
-
2003
- 2003-02-21 NZ NZ52437103A patent/NZ524371A/en not_active IP Right Cessation
- 2003-02-28 GB GB0304668A patent/GB2386773A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB0304668D0 (en) | 2003-04-02 |
| GB2386773A (en) | 2003-09-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PSEA | Patent sealed | ||
| RENW | Renewal (renewal fees accepted) | ||
| RENW | Renewal (renewal fees accepted) | ||
| LAPS | Patent lapsed |