GB2295284A - Circuit breaker - Google Patents
Circuit breaker Download PDFInfo
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- GB2295284A GB2295284A GB9509342A GB9509342A GB2295284A GB 2295284 A GB2295284 A GB 2295284A GB 9509342 A GB9509342 A GB 9509342A GB 9509342 A GB9509342 A GB 9509342A GB 2295284 A GB2295284 A GB 2295284A
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- line
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- 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
- H02H3/338—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 also responsive to wiring error, e.g. loss of neutral, break
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Breakers (AREA)
- Emergency Protection Circuit Devices (AREA)
- Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
Abstract
Circuit interruption is executed in the event of faulty connection of a distribution line, thereby improving safety. Contacts 3, which are opened and closed by drive mechanism 4, are inserted in a main current path between power-supply-side terminal area 1 and load-side terminal area 2. Neutral-line potential response means 10 between legs of the main current path are equipped with a series circuit containing energizing coil 12 and thyristor SCR1, while resistor R2, capacitor C1, and diode D2 are connected in parallel across the gate and cathode of thyristor SCR1. Furthermore, resistor R2 is connected through Zener diode ZD to main-current-path neutral-line-side lead N. In the event of reversal of live and neutral connections, or an open neutral, a potential difference is generated between neutral-line-side lead N and ground connection area 7. As a result, Zener diode ZD passes current, turning ON thyristor SCR1 and opening contacts 3. The circuit also responds to excessive current, and may include an earth leakage detection transformer. <IMAGE>
Description
CIRCUIT BREAKER
The invention concerns a circuit breaker in which abnormal current flowing in a main current path wherein contacts have been inserted results in forced opening of the contacts.
Broadly classified, such circuit breakers have conventionally included the following: circuit breakers for protection of wiring or for load protection in motors and the like, which are provided with a drive mechanism that forces open the contacts in response to excessive current, such as current due to short or overload flowing in the main current path; circuit breakers for protection against electrical leaks, which are provided with a drive mechanism that forces open the contacts in response to output from a zero-phase current transformer which senses electrical leak current such as leak current or ground fault current flowing in the main current path; and circuit breakers possessing the functions of both of the above. These circuit breakers are variously employed to suit the application.
Fig. 7 shows the constitution of a conventional circuit breaker.
A main current path is formed with the insertion of contacts 3 between load-side terminal area 2 and power-supply-side terminal area 1 possessing voltage-line terminal la and neutral-line terminal ib, to which a distribution line's voltage line and neutral line are respectively connected. Actuation coil 5, which actuates drive mechanism 4 and forces open contacts 3 when current due to a short flows in the main current path, and thermal relay 6, which senses generation of heat from overload current flowing in the main current path and actuates the drive mechanism, are inserted in voltage-line-side lead L of the main current path, and zero-phase current transformer CT, the primary side of which is the main current path, is provided.The secondary side of zero-phase current transformer CT is connected to controller 20, which possesses
IC 21, and when the current flowing in the main current path, which is the primary side of zero-phase current transformer CT, becomes unbalanced due to existence of a leak current, an output appears at the secondary side, and this output from zero-phase current transformer CT is input to controller 20. IC 21 of controller 20 operates on full-waverectified voltage due to the connection of diode bridge DB between legs of the main current path through energizing coil 12. At controller 20, thyristor SCR2 is turned ON when output from zero-phase current transformer CT exceeds a prescribed value. This thyristor SCR2 is inserted in the main current path in series with energizing coil 12 for actuation of drive mechanism 4.When SCR2 turns ON, energizing current flows in energizing coil 12, causing actuation of drive mechanism 4 and opening of contacts 3. Furthermore, this circuit breaker is provided with test switch 22. When test switch 22 is turned
ON, it forces supply of primary current to zero-phase current transformer CT, so as to permit testing of the operation whereby controller 20 causes actuation of drive mechanism 4 and opening of contacts 3.
Now, in order to prevent occurrence of abnormal voltages, the distribution line connected to power-supply-side terminal area 1 of the circuit breaker is divided into a neutral line, which is grounded to earth, and a voltage line; corresponding to this, as is described above, powersupply-side terminal area 1 of the circuit breaker is also divided into voltage-line terminal 1 a, to which the voltage line is connected, and neutral-line terminal lb, to which the neutral line is connected. In addition, when the distribution line is connected to the circuit breaker, the distribution-line voltage line must be properly connected to voltageline terminal la, and the distribution line's neutral line must be properly connected to neutral-line terminal lb, of power-supply-side terminal area 1.
However, there is the danger that when connecting the distribution line to the circuit breaker, service personnel might mistakenly connect the voltage line to neutral-line terminal lb, and connect the neutral line to voltage-line terminal 1 a, of the circuit breaker. The problem raises the possibility that the circuit breaker might no longer carry out its prescribed function in the event of such faulty connection.
The purpose of the invention is to solve the aforesaid problems.
As such, the invention endeavors to provide a circuit breaker wherein circuit interruption is carried out in the event of faulty distribution-line connection, thereby affording an improvement in safety.
The invention of Claim 1, in order to accomplish the aforesaid purpose, is, in the context of a circuit breaker wherein a main current path is formed with the insertion of contacts between a load-side terminal area and a power-supply-side terminal area possessing a voltage-line terminal and a neutral-line terminal to which a distribution line's voltage line and neutral line are respectively connected, and equipped with a drive mechanism that opens the contacts and interrupts the main current path when current flowing in the main current path due to short or overload is detected while the contacts are closed, and provided with a ground connection area which is connected to an external ground, and neutral-line potential response means which actuate the drive mechanism and open the contacts when the potential difference between the neutral-line terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value.
The invention of Claim 2, in order to accomplish the aforesaid purpose, is, in the context of a circuit breaker wherein a main current path is formed with the insertion of contacts between a load-side terminal area and a power-supply-side terminal area possessing a voltage-line terminal and a neutral-line terminal to which a distribution-line voltage line and neutral line are respectively connected, and equipped with a zero-phase current transformer which senses electrical leak current such as leak current or ground fault current flowing in the main current path while the contacts are closed, and a drive mechanism that opens the contacts and interrupts the main current path in response to output from this zero-phase current transformer, and provided with a ground connection area which is connected to an external ground and simulated leak current generation means which generate a simulated leak current at the zero-phase current transformer and actuate the drive mechanism when the potential difference between the neutral-line terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value.
The invention of Claim 3 is, in the context of the invention of
Claim 1 or Claim 2, a series circuit containing an energizing coil which actuates the drive mechanism, and a switching element which turns ON when the potential difference between the ground connection area and the neutral-line terminal of the power-supply-side terminal area exceeds a prescribed value, and provided between the ground connection area and the voltage-line terminal of the power-supply-side terminal area.
In the constitution of the invention of Claim 1, as a result of provision of a ground connection area which is connected to an external ground, and neutral-line potential response means which actuate the drive mechanism and open the contacts when the potential difference between the neutral-line terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value, in the event of faulty connection of the distribution line to the power-supplyside terminal area of the circuit breaker a potential difference exceeding a prescribed value will exist between the ground connection area and the neutral-line terminal of the power-supply-side terminal area, thereby causing the neutral-line potential response means to actuate the drive mechanism and force open the contacts, interrupting the main current path.
In the constitution of the invention of Claim 2, as a result of provision of a ground connection area which is connected to an external ground, and simulated leak current generation means which generate a simulated leak current at the zero-phase current transformer and actuate the drive mechanism when the potential difference between the neutralline terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value, in the event of faulty connection of the distribution line to the power-supply-side terminal area of the circuit breaker a potential difference exceeding a prescribed value will exist between the ground connection area and the neutralline terminal of the power-supply-side terminal area, thereby causing the simulated leak current generation means to cause generation of output at the zero-phase current transformer and to actuate the drive mechanism, forcing open the contacts and interrupting the main current path.
In the constitution of the invention of Claim 3, as a result of provision, between the ground connection area and the voltage-line terminal of the power-supply-side terminal area, of a series circuit containing an energizing coil which actuates the drive mechanism, and a switching element which turns ON when the potential difference between the ground connection area and the neutral-line terminal of the power-supply-side terminal area exceeds a prescribed value, when an open line in the neutral-line pathway occurs to the power-supply side of the power-supply-side terminal area, or occurs to the power-supply side of the neutral-line potential response means or simulated leak current generation means, with the distribution line properly connected to the power-supply-side terminal area of the circuit breaker, a potential difference will exist between the ground connection area and the neutral-line terminal as a result of current flowing from the voltageline-side lead of the main current path, through the load, to the ground connection area, thereby turning ON the switching element and supplying current to the energizing coil, causing the energizing coil to be energized, the drive mechanism to be actuated, and the contacts to be opened. Opening of the contacts and interruption of the main current path is therefore also permitted if an open occurs in the neutral line when connections have been properly made, thus affording an improvement in circuit breaker safety.
The effectiveness of the invention of Claim 1 is, in the context of a circuit breaker wherein a main current path is formed with the insertion of contacts between a load-side terminal area and a powersupply-side terminal area possessing a voltage-line terminal and a neutral-line terminal to which a distribution line's voltage line and neutral line are respectively connected, and equipped with a drive mechanism that opens the contacts and interrupts the main current path when current flowing in the main current path due to short or overload is sensed while the contacts are closed, inasmuch as the invention is provided with a ground connection area which is connected to an external ground, and neutral-line potential response means which actuate the drive mechanism and open the contacts when the potential difference between the neutral-line terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value, to cause generation of a potential difference exceeding a prescribed value between the ground connection area and the neutralline terminal of the power-supply-side terminal area in the event of faulty connection of the distribution line to the power-supply-side terminal area of the circuit breaker, and to consequently allow the neutral-line potential response means to actuate the drive mechanism, force open the contacts, and interrupt the main current path, thereby affording assurance of safety in the event of faulty connection, as well as permitting prevention of faulty connection during wiring servicing.
The effect of the invention of Claim 2 is, in the context of a circuit breaker wherein a main current path is formed with the insertion of contacts between a load-side terminal area and a power-supply-side terminal area possessing a voltage-line terminal and a neutral-line terminal to which a distribution line's voltage line and neutral line are respectively connected, and equipped with a zero-phase current transformer which senses electrical leak current such as leak current or ground fault current flowing in the main current path while the contacts are closed, and a drive mechanism that opens the contacts and interrupts the main current path in response to output from this zerophase current transformer, inasmuch as the invention is provided with a ground connection area which is connected to an external ground, and simulated leak current generation means which generate a simulated leak current at the zero-phase current transformer and actuate the drive mechanism when the potential difference between the neutral-line terminal of the power-supply-side terminal area and this ground connection area exceeds a prescribed value, to cause generation of a potential difference exceeding a prescribed value between the ground connection area and the neutral-line terminal of the power-supply-side terminal area in the event of faulty connection of the distribution line to the power-supply-side terminal area of the circuit breaker, and to consequently allow the simulated leak current generation means to cause generation of output at the zero-phase current transformer, actuate the drive mechanism, force open the contacts, and interrupt the main current path, thereby affording assurance of safety in the event of faulty connection, as well as permitting prevention of faulty connection during wiring servicing.
In the constitution of the invention of Claim 3, inasmuch as a series circuit containing an energizing coil which actuates the drive mechanism, and a switching element which turns ON when the potential difference between the ground connection area and the neutral-line terminal of the power-supply-side terminal area exceeds a prescribed value is provided between the ground connection area and the voltage-line terminal of the power-supply-side terminal area, the effect of the invention, when the neutral line pathway opens on the power-supply side of the power-supply-side terminal area or on the power-supply side of the neutral-line potential response means or simulated leak current generation means with the distribution line properly connected to the power-supply-side terminal area of the circuit breaker, is to cause generation of a potential difference between the ground connection area and the neutral-line terminal as a result of current flowing from the voltage-line-side lead of the main current path, through the load, to the ground connection area, thereby turning ON the switching element and supplying current to the energizing coil, causing the energizing coil to be energized, the drive mechanism to be actuated, and the contacts to be opened. Opening of the contacts and interruption of the main current path is therefore also permitted if the neutral line opens when connections have been properly made, thus affording an improvement in circuit breaker safety.
A number of embodiments of the invention will now be described. by way of eenple only, with reference to the accanpanying drawings in which:
Fig. I shows the constitution of the circuitry of first Embodiment.
Fig. 2 shows the constitution of the circuitry of second Embodiment.
Fig. 3 shows the constitution of the circuitry of third Embodiment.
Fig. 4 shows another example of the principal parts of the above.
Fig. 5 shows the constitution of the circuitry of fourth Embodiment.
Fig. 6 shows the constitution of the circuitry of fifth Embodiment.
Fig. 7 shows the constitution of the circuitry of an example from related art.
< first Embodiment >
Fig. 1 shows the constitution of the circuitry of the circuit breaker of this embodiment. This circuit breaker is of the so-called 2P1E type, wherein the main current path is formed with the insertion of contacts 3 between load-side terminal area 2, which possesses a pair of load connection terminals 2a and 2b, and power-supply-side terminal area 1, which possesses voltage-line terminal la and neutral-line terminal lb, to which the distribution line's voltage line and neutral line are respectively connected, such that actuation coil 5, which actuates drive mechanism 4 and forces open contacts 3 when current due to a short flows in the main current path, and thermal relay 6, which senses generation of heat from overload current flowing in the main current path and actuates drive mechanism 4, are inserted in voltage-line-side lead L of the main current path. Furthermore, drive mechanism 4 possesses a commonly known structure whereby it is equipped with handle 4a for manual opening and closing of contacts 3.
Moreover, this circuit breaker is provided with ground connection area 7, which is connected to an external ground, and with neutral-line potential response means 10 between the main current path and ground connection area 7, to the load side of contacts 3.
The neutral-line potential response means 10 are equipped with voltage-line-side terminal 11 a, neutral-line-side terminal 1 lb, and ground terminal 11 c which are respectively connected to main-currentpath voltage-line-side lead L, neutral-line-side lead N, and ground connection area 7. The series circuit containing diode D3, energizing coil 12, and thyristor SCR, is connected between voltage-line-side terminal 1 la and ground terminal 1 lc. Furthermore, the series circuit containing diode D4, resistor R1, diode D,, Zener diode ZD, and resistor
R2 is connected in parallel with energizing coil 12 and thyristor SCR, between ground terminal 1 lc and the junction between diode D3 and energizing coil 12.Moreover, the two ends of resistor R2 are connected, through the intervening parallel circuit containing capacitor C, and diode D2, to the gate and cathode of thyristor SCR,. Furthermore, the anode of thyristor SCR, is connected to the anode of diode D4 through resistor R3. Two surge absorbing elements ZN, and ZN2 are connected between voltage-line-side terminal 1 la and neutral-line-side terminal 1 lib such that they straddle energizing coil 12, and surge absorbing element ZN3 is connected between neutral-line-side terminal 1 ib and ground terminal 11 c.
Next, we describe the operation of neutral-line potential response means 10. First, when the distribution line's voltage line and neutral line are properly connected to voltage-line terminal la and neutral-line terminal 1 b of power-supply-side terminal area 1 of the circuit breaker, almost no potential difference will exist between voltage-line-side terminal 1 la and neutral-line-side terminal 1 ib of neutral-line potential response means 10, because the neutral line is grounded. Accordingly, since Zener diode ZD does not pass current, thyristor SCR, remains OFF and no current flows at energizing coil 12, so that drive mechanism 4 is not actuated.From this state, however, should current flow in the main current path due to short or overload, actuation coil 5 and thermal relay 6 will cause actuation of drive mechanism 4 and opening of contacts 3.
On the other hand, when the distribution line's voltage line and neutral line are respectively reversed due to faulty connection to voltage-line terminal I a and neutral-line terminal 1 b of power-supplyside terminal area 1 of the circuit breaker, main-current-path neutralline-side lead N, which by rights should be connected to the neutral line, will instead be connected to the voltage line. As a result, a potential difference will exist between neutral-line-side lead N and ground connection area 7, and a potential difference will exist between neutralline-side terminal 1 ib and ground terminal 1 lc of neutral-line potential response means 10 as well.Whereupon, if this potential difference exceeds the Zener voltage, Zener diode ZD will pass current, turning
ON thyristor SCAR1. When thyristor SCR, goes ON, a conductive path will exist between one end of energizing coil 12 and ground connection area 7, through thyristor SCR,. As a result, current flows along the route neutral-line-side terminal 1 lb -- diode D4 -- energizing coil 12 -- thyristor SCAR, -- ground terminal 1 c, causing actuation of drive mechanism 4, opening of contacts 3, and interruption of the main current path.
Since, in the event of faulty connection of the distribution line's voltage line and neutral line to voltage-line terminal la and neutral-line terminal lb of power-supply-side terminal area 1 of the circuit breaker, neutral-line potential response means 10 cause actuation of drive mechanism 4 and opening of contacts 3, thereby interrupting the circuit to prevent power-supply voltage from being supplied to the load side while a faulty connection exists, adoption of the aforesaid constitution permits prevention of occurrence of a service mishap during connection of the distribution line.
< second Embodiment >
Fig. 2 shows the constitution of the circuitry of the circuit breaker of this embodiment. As shown in Fig. 2, the fundamental constitution of the circuitry of this circuit breaker is generally the same as that of the example from the related art shown in Fig. 7. Common elements are marked identically and their description is omitted, the description here being limited to only those elements that are characteristic of this embodiment.
As in first Embodiment, this embodiment is provided with ground connection area 7, which is connected to an external ground.
Surge absorbing element ZN3 and the series circuit containing resistor Rl, diode D,, Zener diode ZD, and resistor R2 are connected between this ground connection area 7 and main-current-path neutral-line-side lead N. Also, the two ends of resistor R2 are connected through resistor
R4 to light-emitting diode LED, of which photocoupler PC is comprised.
Moreover, at controller 20, energizing coil 12 and thyristor SCR2,, which is connected in series thereto, can be triggered not only by the gate voltage, but by emission of light from light-emitting diode
LED as well. Photocoupler PC is constituted by light-emitting diode
LED and thyristor SCR2.
Next, we describe the operation of the circuit breaker of this embodiment. First, with the distribution line properly connected to power-supply-side terminal area 1, flow of current due to short or overload results in actuation of drive mechanism 4 by either actuation coil 5 or thermal relay 6, causing opening of contacts 3. Alternatively, flow of electrical leak current such as leak current or ground fault current results in imbalance in the current flowing at the primary side of zero-phase current transformer CT, and production Qf output at the secondary side.At controller 20, when output at the secondary side of zero-phase current transformer CT exceeds a prescribed value, IC 21 turns ON thyristor SCR2,. As a result, current flows along the route voltage-line-side lead L -- energizing coil 12 -- thyristor SCR2' -- diode bridge DB -- neutral-line-side lead N, drive mechanism 4 is actuated, and contacts 3 are opened. Also, actuation of test switch 22 forces the primary current of zero-phase current transformer CT to become unbalanced, causing actuation of drive mechanism 4 and opening of contacts 3 in the same manner as occurs with leak current.
On the other hand, when there is faulty connection of the distribution-line voltage line and neutral line to voltage-line terminal la and neutral-line terminal 1 b of power-supply-side terminal area 1, a potential difference will exist between main-current-path neutral-lineside lead N and ground connection area 7, and, if this potential difference exceeds the Zener voltage, Zener diode ZD will pass current, causing light-emitting diode LED to light. As a result, thyristor SCR2,, which is optically coupled to light-emitting diode LED, turns ON.
When thyristor SCR2' goes ON, current will flow to energizing coil 12 through thyristor SCR2, and diode bridge DB, causing actuation of drive mechanism 4 and opening of contacts 3.
As described above, in the event of faulty connection of the distribution line, this embodiment causes current to flow to energizing coil 12 when a potential difference exceeding the Zener voltage of
Zener diode ZD exists between neutral-line-side lead N and ground connection area 7. Hence, neutral-line potential response means 10' are constituted by the series circuit containing resistor R1 and so forth and
Zener diode ZD, photocoupler PC, and energizing coil 12.
< third Embodiment >
Fig. 3 shows the constitution of the circuitry of the circuit breaker of this embodiment. As shown in Fig. 3, the fundamental constitution of the circuitry of this circuit breaker is generally the same as that of the example from the related art shown in Fig. 7. Common elements are marked identically and their description is omitted.
As in first Embodiment, the circuit breaker of this embodiment is provided with ground connection area 7, which is connected to an external ground, while primary coil nl of zero-phase current transformer CT is provided between this ground connection area 7 and main-current-path neutral-line-side lead N, through resistor R5. In addition, surge absorbing element ZN4 is inserted between ground connection area 7 and neutral-line-side lead N.
Next, we describe the operation of the circuit breaker of this embodiment. First, with the distribution line properly connected to power-supply-side terminal area 1, flow of current due to short or overload results in actuation of drive mechanism 4 by either actuation coil 5 or thermal relay 6, causing opening of contacts 3. Alternatively, flow of electrical leak current such as leak current or ground fault current results in imbalance in the current flowing at the primary side of zero-phase current transformer CT, and production of output at the secondary side. At controller 20, when output at the secondary side of zero-phase current transformer CT exceeds a prescribed value, IC 21 turns ON thyristor SCR2.As a result, current flows along the route voltage-line-side lead L -- energizing coil 12 -- thyristor SCR2 -- diode bridge DB -- neutral-line-side lead N, drive mechanism 4 is actuated, and contacts 3 are opened. Also, actuation of test switch 22 forces the primary current of zero-phase current transformer CT to become unbalanced, causing actuation of drive mechanism 4 and opening of contacts 3 in the same manner as occurs with leak current.
On the other hand, when there is faulty connection of the distribution line's voltage line and neutral line to voltage-line terminal la and neutral-line terminal ib of power-supply-side terminal area 1, a potential difference will exist between main-current-path neutral-lineside lead N and ground connection area 7, and current will consequently flow at primary coil nl, which is provided between the two. Because the current flowing at primary coil nl causes the primary side of zero-phase current transformer CT to become unbalanced, output is produced at the secondary side of zero-phase current transformer CT, and thyristor SCR2 turns ON at controller 20.When thyristor SCR2 turns ON, current flows to energizing coil 12 through thyristor SCR2 and diode bridge DB, causing actuation of drive mechanism 4 and opening of contacts 3.
In the event of faulty connection of the distribution line to power-supply-side terminal area 1, adoption of the aforesaid constitution permits generation of output at the secondary side of zerophase current transformer CT by virtue of the simulated leak current generation means comprising primary coil nl of zero-phase current transformer CT, provided between main-current-path neutral-line-side lead N and ground connection area 7. Hence, in the event of the aforesaid faulty connection, simulated generation of the secondary-side output of zero-phase current transformer CT intended to be produced in the event of a leak causes controller 20 to actuate drive mechanism 4 and open contacts 3. Furthermore, as shown in Fig. 4, the series circuit containing resistor R5, diode D5, and Zener diode ZD2 may be inserted in place of resistor R5, which is connected in series with primary coil nl. This will then result in no current flowing at primary coil nl of zero-phase current transformer CT so long as the potential difference between neutral-line-side lead N and ground connection area 7 does not exceed the Zener potential of Zener diode ZD2. As a result, the small potential difference existing between neutral-line-side path N and ground connection area 7 when the distribution line is properly connected to power-supply-side terminal area 1 will not cause current to flow at primary coil nl, and malfunction can thereby be prevented.
< fourth Embodiment >
Fig. 5 shows the constitution of the circuitry of the circuit breaker of this embodiment. As shown in Fig. 5, the fundamental constitution of the circuitry of this circuit breaker is generally the same as that of the example from the prior art and third Embodiment.
Common elements are marked identically and their description is omitted, the description here being limited to only those elements that are characteristic of this embodiment.
In the circuit breaker of this embodiment, thyristor SCR3 is connected between ground connection area 7 and the junction of energizing coil 12 and the input end of diode bridge DB in the circuit breaker of third Embodiment. Also, the series circuit containing resistor R3, diode D4, Zener diode ZD3, and resistor R5 is inserted in place of resistor R3, which had been inserted between primary coil nl and ground connection area 7. In addition, capacitor C2, diode D5, and the gate and cathode of thyristor SCR3 are respectively connected in parallel to the two ends of resistor R5.
Next, we describe the operation of the circuit breaker of this embodiment. Incidentally, since operation when current flows due to short or overload, or due to electrical leak such as leak or ground fault with the distribution line properly connected to power-supply-side terminal area 1 is the same as that of the example from the prior art and third Embodiment, description is omitted.
Now, with the distribution line properly connected to power supply-side terminal area 1, the distribution line's neutral line may open or come loose on the power-supply side of power-supply-side terminal area l, or may open on the power-supply side of the point where the series circuit containing energizing coil 12 and thyristor SCR3 is connected to the main current path. In such case, current will flow from main-current-path voltage-line-side lead L, through load-side terminal area 2 and the load connected to load-side terminal area 2, to ground connection area 7. As a result, a potential difference will occur at load-side terminal area 2 despite the fact that power is not supplied to the load.
When such a potential difference exists, if this potential difference exceeds the Zener voltage of Zener diode ZD3, gate voltage will be applied at thyristor SCR3, turning ON thyristor SCR3 and causing current to flow along the route of main-current-path voltageline-side lead L -- energizing coil 12 -- thyristor SCR3 -- ground connection area 7, thereby causing actuation of drive mechanism 4 and opening of contacts 3.
With the distribution line properly connected to power-supplyside terminal area 1, adoption of the aforesaid constitution permits actuation of drive mechanism 4 and opening of contacts 3 as a result of current being caused to flow at energizing coil 12 in the event that the neutral line opens or comes loose, or the like. Consequently, improved circuit breaker safety is thereby afforded.
< fifth Embodiment >
Whereas aforesaid first Embodiment to fourth Embodiment concern the case wherein the distribution line has 2 lines, the circuit breaker of this embodiment is for a distribution line having 3 lines. Fig.
6 shows the constitution of the circuitry of this embodiment. As the fundamental constitution of the circuitry is the same as that of the fourth Embodiment circuit breaker for a distribution line having 2 lines, common elements are marked identically and their description is omitted.
In this embodiment, 1 of the 3 lines of the distribution line is the neutral line, while the remaining 2 lines are voltage lines. A total of 3 terminals -- 2 voltage-line terminals la and lc, and neutral-line terminal lb -- are provided at power-supply-side terminal area 1. Three terminals are likewise provided at load-side terminal area 2, and the main current path formed possesses 2 voltage-line-side leads L, and L2, and neutral-line-side lead N, wherein contacts 3 are inserted. Actuation coil 5 and thermal relay 6 are respectively inserted within the 2 voltage-line-side leads L1 and L2. Furthermore, zero-phase current transformer CT, the primary side of which is the main current path, is provided.Test switch 22 is inserted between the 2 voltage-line-side leads L1 and L2, and surge absorbing element ZN4 is inserted between 1 of the voltage-line-side leads L2 and neutral-line-side lead N.
Resistor R6, and capacitors C3 and C4 are connected in series between energizing coil 12 and the input side of diode bridge DB of controller 20. Furthermore, between thyristor SCR2 and one end of energizing coil 12, another thyristor SCR4 is connected. The gate of this thyristor SCR4 is connected through resistor R7 to the junction between capacitor C3 and capacitor C4. Resistor R8 and capacitor C5 are connected in parallel across the gate and cathode of thyristor SCR4.
Next, we describe the operation of the circuit breaker of this embodiment. First, with the distribution line properly connected to power-supply-side terminal area 1, flow of current due to short or overload results in actuation of drive mechanism 4 by either actuation coil 5 or thermal relay 6, causing opening of contacts 3. Alternatively, flow of electrical leak current such as leak current or ground fault current results in imbalance in the current flowing at the primary side of zero-phase current transformer CT, and production of output at the secondary side. At controller 20, when output at the secondary side of zero-phase current transformer CT exceeds a prescribed value, IC 21 turns ON thyristor SCR2. When thyristor SCR2 turns ON, capacitor C5 is charged through resistor R7, applying voltage to the gate of thyristor
SCR4 and turning ON thyristor SCR4.As a result, current flows along the route of voltage-line-side lead L, -- energizing coil 12 -- thyristor SCR4 -- thyristor SCR2 -- diode bridge DB -- voltage-line-side lead L2, drive mechanism 4 is actuated, and contacts 3 are opened. Actuation of test switch 22 forces the primary current of zero-phase current transformer CT to become unbalanced, causing actuation of drive mechanism 4 and opening of contacts 3 in the same manner as occurs with leak current.
On the other hand, when there is faulty connection of the distribution line's voltage lines and neutral line to voltage-line terminals 1a and l c and neutral-line terminal lb of power-supply-side terminal area 1, a potential difference will exist between main-currentpath neutral-line-side lead N and ground connection area 7, and current will consequently flow at primary coil nl, which is provided between the two. Because the current flowing at primary coil nl causes the primary side of zero-phase current transformer CT to become unbalanced, output is produced at the secondary side of zero-phase current transformer CT, and thyristors SCR2 and SCR4 turn ON at controller 20.As a result, current flows to energizing coil 12 through thyristors SCR2 and SCR4 and diode bridge DB, causing actuation of drive mechanism 4 and opening of contacts 3.
Furthermore, as in fourth Embodiment, with the distribution line properly connected to power-supply-side terminal area 1, in the event that the distribution line's neutral line opens or comes loose on the power-supply side of power-supply-side terminal area 1, or opens on the power-supply side of the point where the series circuit containing energizing coil 12 and thyristor SCR3 is connected to the main current path, current will flow from main-current-path voltageline-side lead Ll, through load-side terminal area 2 and the load connected to load-side terminal area 2, to ground connection area 7. As a result, a potential difference will occur at load-side terminal area 2, and, if this potential difference exceeds the Zener voltage of Zener diode ZD3, gate voltage will be applied at thyristor SCAR3, turning ON thyristor SCR3 and causing current to flow along the route of maincurrent-path voltage-line-side lead L, -- energizing coil 12 -- thyristor
SCR3 -- ground connection area 7, thereby causing actuation of drive mechanism 4 and opening of contacts 3.
Claims (5)
1. A circuit breaker comprising:
a power terminal section for connection with a distribution line composed of a voltage line and a neutral line, said power terminal section comprised of a line terminal for connection with said voltage line and a neutral terminal for connection with said neutral line;
a load terminal section for connection with a load;
a contact disposed in a main current path between said power terminal section and said load terminal section; and
a drive mechanism which opens said contact for interrupting said main current path when a shorting current or an overload current is detected to flow through the main current path, wherein neutral line voltage responsive means is provided to detect a voltage difference between said neutral line at a point offset from said contact towards said power terminal and a ground terminal for connection with an external ground, said means actuating said drive mechanism for opening the contact when said detected voltage difference becomes greater than a predetermined value.
2. A circuit breaker comprising:
a power terminal section for connection with a distribution line composed of a voltage line and a neutral line, said power terminal section comprised of a line terminal for connection with said voltage line and a neutral terminal for connection with said neutral line;
a load terminal section for connection with a load;
a contact disposed in a main current path between said power terminal section and said load terminal section;
a zero-phase current transformer which detects a leakage current such as a shorting current or leak current and provides an output when said leakage current is detected; and
a drive mechanism which opens said contact for interrupting said main current path in response to the output of said zero-phase detector, wherein neutral line voltage responsive means is provided to detect a voltage difference between said neutral line at a point offset from said contact towards said power terminal and a ground terminal for connection with an external ground, said means providing a pseudo leakage current for actuating said drive mechanism to open the contact when said detected voltage difference becomes greater than a predetermined value.
3. The circuit breaker as set forth in claim 1 or 2, wherein an excitation coil for actuating said drive mechanism is connected in series with a switching element between said voltage line at a point offset from the contact towards the power terminal section and said ground terminal, said switching element being caused to turn on when the voltage difference between said neutral line at a point offset from said contact towards said power terminal and said ground terminal becomes greater than the predetermined value.
4. A circuit breaker comprising:
first and second terminals for connection to respectively the live and neutral lines of a distribution system; and
means for activating the circuit breaker to interrupt the supply to an external load in the event the second terminal is connected to the live line.
5. A circuit breaker substantially as hereinbefore described with reference to Figures 5 and 6 of the accompanying drawings.
5. A circuit breaker substantially as hereinbefore described with reference to Figures 1 to 6 of the accompanying drawings.
Amendments to the claims have been filed as follows 1. A circuit breaker comprising:
a power terminal section for connection with a distribution line composed of a voltage line and a neutral line, said power terminal section comprised of a line terminal for connection with said voltage line and a neutral terminal for connection with said neutral line;
a load terminal section for connection with a load;
a contact disposed in a main current path between said power terminal section and said load terminal section; and
a drive mechanism which opens said contact for interrupting said main current path when a shorting current or an overload current is detected to flow through the main current path,
wherein a neutral line voltage responsive means is provided to detect a voltage difference between said neutral line at a point offset from said contact towards said power terminal and a ground terminal for connection with an external ground, said means actuating said drive mechanism for opening the contacts of said voltage line and said neutral line when said detected voltage difference becomes greater than a predetermined value.
2. The circuit breaker as set forth in claim 1, wherein an excitation coil for actuating said drive mechanism is connected in series with a switching element between said voltage line at a point offset from the contact towards the power terminal section and said ground terminal, said switching element being caused to turn on when the voltage difference between said neutral line at a point offset from said contact towards said power terminal and said ground terminal becomes greater than the predetermined value.
3. A circuit breaker comprising:
a power terminal section for connection with a distribution line composed of a voltage line and a neutral line, said power terminal section comprised of a line terminal for connection with said voltage line and a neutral terminal for connection with said neutral line;
a load terminal section for connection with a load;
a contact disposed in a main current path between said power terminal section and said load terminal section;
a zero-phase current transformer which detects a leakage current such as a shorting current or leak current and provides an output when said leakage current is detected; and
a drive mechanism which opens said contact for interrupting said main current path in response to the output of said zero-phase detector,
wherein a neutral line voltage responsive means is provided to detect a voltage difference between said neutral line at a point offset from said contact towards said power terminal and a ground terminal for connection with an external ground, said means providing a pseudo leakage current for actuating said drive mechanism to open the contact when said detected voltage difference becomes greater than a predetermined value,
wherein an excitation coil for actuating said drive mechanism is connected in series with a switching element between said voltage line at a point offset from the contact towards the power terminal section and said ground terminal, said switching element being caused to turn on when the voltage difference between said neutral line at a point offset from said contact towards said power terminal and said ground terminal becomes greater than the predetermined value.
4. A circuit breaker substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6281026A JP2992449B2 (en) | 1994-11-15 | 1994-11-15 | Circuit breaker |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9509342D0 GB9509342D0 (en) | 1995-06-28 |
| GB2295284A true GB2295284A (en) | 1996-05-22 |
| GB2295284B GB2295284B (en) | 1999-02-03 |
Family
ID=17633259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9509342A Expired - Fee Related GB2295284B (en) | 1994-11-15 | 1995-05-09 | Circuit breaker |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2992449B2 (en) |
| CN (1) | CN1046055C (en) |
| GB (1) | GB2295284B (en) |
| HK (1) | HK1012129A1 (en) |
| MY (1) | MY115956A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2311177A (en) * | 1996-03-13 | 1997-09-17 | Crabtree Electrical Ind Ltd | Residual current device with missing neutral protection |
| GB2376360A (en) * | 2001-06-08 | 2002-12-11 | Delta Electrical Ltd | Measuring residual current and power consumption |
| EP4084251A4 (en) * | 2020-11-13 | 2023-08-30 | Huawei Digital Power Technologies Co., Ltd. | Power source reverse connection prevention circuit, power distribution apparatus, and power supply and distribution system |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4931754B2 (en) * | 2007-10-03 | 2012-05-16 | 三菱電機株式会社 | Earth leakage breaker |
| JP5231061B2 (en) * | 2008-03-27 | 2013-07-10 | テンパール工業株式会社 | Circuit breaker |
| JP5319949B2 (en) * | 2008-03-31 | 2013-10-16 | パナソニック株式会社 | Wiring equipment |
| JP2009245791A (en) * | 2008-03-31 | 2009-10-22 | Panasonic Electric Works Co Ltd | Wiring instrument |
| JP5166174B2 (en) * | 2008-09-03 | 2013-03-21 | テンパール工業株式会社 | Circuit breaker |
| CN103003629B (en) * | 2010-05-07 | 2017-07-18 | 飞利浦照明控股有限公司 | Lamp for substituting fluorescent tube |
| CN102882227B (en) * | 2012-09-14 | 2015-03-18 | 江苏兆伏新能源有限公司 | High-power photovoltaic grid-connected inverter |
| US11935712B2 (en) * | 2018-07-31 | 2024-03-19 | Panasonic Intellectual Property Management Co., Ltd. | Control system and interrupter system |
| CN111509710B (en) * | 2020-04-29 | 2022-01-18 | 广东电网有限责任公司韶关供电局 | TN-C platform area electric leakage identification method, system, equipment and storage medium |
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- 1994-11-15 JP JP6281026A patent/JP2992449B2/en not_active Expired - Lifetime
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- 1995-05-09 GB GB9509342A patent/GB2295284B/en not_active Expired - Fee Related
- 1995-05-16 MY MYPI95001286A patent/MY115956A/en unknown
- 1995-05-24 CN CN95105294A patent/CN1046055C/en not_active Expired - Fee Related
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|---|---|---|---|---|
| US4068276A (en) * | 1976-07-14 | 1978-01-10 | Interelectronics Corporation | Protective system for electrical appliances |
| GB2135542A (en) * | 1983-02-19 | 1984-08-30 | Ashley Accessories Ltd | Earth leakage circuit breaker |
| GB2152775A (en) * | 1983-11-28 | 1985-08-07 | B & R Electrical Prod Ltd | Reversed conductors auto-tripping system |
| GB2150374A (en) * | 1983-12-08 | 1985-06-26 | Ashley Accessories Ltd | Fault detection circuitry |
| GB2201055A (en) * | 1984-07-30 | 1988-08-17 | Technology Res Corp | Ground fault current interrupter circuit with additional protection |
| GB2204199A (en) * | 1987-05-02 | 1988-11-02 | Ashley Accessories Ltd | Residual current circuit breaker |
| GB2215149A (en) * | 1988-02-08 | 1989-09-13 | Shakira Ltd | Ground fault current interrupter with open neutral/ground lead operation |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2311177A (en) * | 1996-03-13 | 1997-09-17 | Crabtree Electrical Ind Ltd | Residual current device with missing neutral protection |
| GB2311177B (en) * | 1996-03-13 | 2000-08-02 | Crabtree Electrical Ind Ltd | Residual current devices |
| GB2376360A (en) * | 2001-06-08 | 2002-12-11 | Delta Electrical Ltd | Measuring residual current and power consumption |
| GB2376360B (en) * | 2001-06-08 | 2005-08-24 | Delta Electrical Ltd | Measuring device |
| GB2412511A (en) * | 2001-06-08 | 2005-09-28 | Eaton Electric Ltd | Measuring residual current and power consumption |
| GB2412511B (en) * | 2001-06-08 | 2005-11-30 | Eaton Electric Ltd | Measuring devices |
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| US7221142B2 (en) | 2001-06-08 | 2007-05-22 | Eaton Electric Limited | Measuring devices |
| EP4084251A4 (en) * | 2020-11-13 | 2023-08-30 | Huawei Digital Power Technologies Co., Ltd. | Power source reverse connection prevention circuit, power distribution apparatus, and power supply and distribution system |
| US11936175B2 (en) | 2020-11-13 | 2024-03-19 | Huawei Digital Power Technologies Co., Ltd. | Reverse power connection preventing circuit, power distribution apparatus, and power supply and distribution system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1118108A (en) | 1996-03-06 |
| GB2295284B (en) | 1999-02-03 |
| JPH08138523A (en) | 1996-05-31 |
| JP2992449B2 (en) | 1999-12-20 |
| CN1046055C (en) | 1999-10-27 |
| GB9509342D0 (en) | 1995-06-28 |
| HK1012129A1 (en) | 1999-07-23 |
| MY115956A (en) | 2003-10-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) |
Effective date: 20010829 |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20050509 |