DK150056B - CIRCUIT FOR ENERGY SUPPLY TO A FUNCTIONAL EQUIPMENT, FX A DETECTOR FOR EQUIPMENT - Google Patents

Description

150056

The present invention relates to an energy supply circuit for a functional apparatus, in particular a safety apparatus such as a ground leakage current detector, which apparatus is adapted to be connected to an electrical installation having an earth electrode and supplied from the phase current of an AC power supply. and zero wires, and wherein said circuit has a rectifier circuit having a first, second, and third terminals serving respectively for phase, zero wiring in the network and with the ground electrode, so that the rectifier circuit is powered at least through the ground electrode. a break in the zero lead or a wire connecting the zero lead to the rectifier circuit.

In such a case, in the said wire on its rectifier circuit side, i.e. at the second terminal, be a voltage which can assume any value between zero and the phase voltage via the load impedance generated by the installation to be powered. Accordingly, a supply voltage is provided between the rectifier circuit on the other terminal, which is separated from the mains lead, on the one hand, and the third terminal of the rectifier circuit connected to the ground electrode on the other. The mains lead and the rectifier circuit's other terminal connected thereto will also reach a specific voltage due to a break in the mains phase line if a voltage-carrying part of the phase line comes into contact with the zero line. Also, in that case, a supply voltage will be available between the second terminal connected to the zero wire, on the one hand, and the third terminal of the rectifier circuit connected to the ground electrode, on the other. It is clear that in both cases the operation of the power supply can be continued.

- In energy supply circuits for a leakage current detector of this kind as described in the specification to British Patent No. 1,107,879, the zero conductor and the phase conductor of the main and ground electrodes together with the mains ground wire are thus connected via mcsistarrde to the relevant terminals on the rectifier circuit. perpendicularly from the phase lead to the ground electrode, but also to the zero conductor depending on the values of the resistors selected.

Although advisable in some cases, e.g. in order to establish a short-circuit between the neutral conductor and the earth electrode that the rectifier circuit is energized via the earth electrode even during normal operation, the permanent presence of a current through the earth electrode is undesirable or in some cases prohibited. This limits the possibilities of using the energy supply shown in the UK description and detectors for leakage to the ground power supply.

The object of the present invention is to provide an improvement in this regard and to provide an energy supply circuit for a functional apparatus, for example a security apparatus in the form of a ground leakage detector, where the supply current flows normally through the phase line mainly or only to the zero line. while in the event of a break in the zero lead, it runs via the phase lead to the earth electrode.

According to the invention, the energy supply circuit of the above-described type according to the invention is characterized in that the third terminal is connected to said rectifier circuit via a second rectifier circuit. The consequence is that any summing up of the supply voltages supplied to the energy supply through the various terminals will always take place on the direct current side of the rectifier circuits and not on the alternating current side. In the event of a power line failure, the power supply will be taken over by the other circuit.

Where an energy supply circuit is used in which the rectifier circuit is of a half-wave type and comprises a rectifier element, an electrode of which is connected to the first terminal for connection to the phase line in the network, according to a simple embodiment of the invention, the rectifier element is coupled to the third terminal via an additional rectifier element. for connection to the ground electrode.

3 150056

The invention may similarly be embodied in the case of an energy supply circuit in which the rectifier circuit is of the full-wave type and comprises a parallel circuit of at least two series circuits of each two alternately operative rectifier elements, where the connection point of the elements of the first series circuit is coupled to the first terminal for connection to the phase circuit. in the network, and the connection point of the elements of the second series circuit is connected to the other terminal for connection to the zero line in the network. In this case, the invention provides a third series circuit of two rectifier elements, wherein said third series circuit is coupled in parallel with the parallel circuit and having its connection point coupled to the third terminal for connection to the ground electrode.

It should be emphasized that where the term phase conduit is used, it does not refer solely to a single-phase AC mains lead. It is equally possible that a three-phase main line with three phase lines and a zero line can be used instead, since the energy supply circuit comprises a three-phase rectifier circuit in this case. An energy supply circuit of this kind according to the invention differs from the energy supply circuit according to the invention as described in the previous section in that it comprises a separate fourth and fifth series circuits each consisting of two rectifier elements, said series circuit being connected in parallel with the complete parallel circuit, the connection points of the rectifier elements are connected to a fourth and a fifth terminal respectively for connection to the other two phase lines in a three-phase alternating current network. Since, according to the invention, the only factor is the alternative mode of supply via the mains lead or the ground electrode, there is no specific difference to be highlighted in the following between single-phase or multi-phase power supplies and rectifier circuits.

The invention will now be described in more detail with reference to the drawing, in which FIG. 1 is a diagram partly in the form of a block diagram showing an energy supply circuit from alternating current 150056 4 pipes for an installation blinded with a ground leakage current detector with an energy supply circuit according to the invention; FIG. 2 is a corresponding diagram of FIG. 1, in which the power supply installation is connected to a ground leakage current detector according to another embodiment of the invention; and FIG. 3A, 3B and 3C are circuit diagrams of some embodiments of energy supply circuits of the invention suitable for use in circuits of FIG. 1 and 2.

FIG. 1 is a diagram showing an energy supply circuit for an electrical installation shown in the drawing simply in the form of a load impedance 5 from the phase line 1 to the zero line 2 in an AC mains 3.

In addition to an earth electrode 9, a functional apparatus with a general reference 6 is also connected to the electrical installation 5 and this apparatus consists in the present case of a ground leakage current detector for controlling a leakage circuit breaker 4 arranged to break the connection between the installation 5 and conductors 1 and 2 in the main conduit 3.

Since the operation of the ground leakage detector as such is not part of the invention, FIG.

1 only the components of the detector schematically. These components are designed as an electronic unit 16 which is powered by the supply lines 14 and 15 from an energy supply circuit 10, to be described below, the unit 16 being coupled via a winding Wj to a soft magnetic circuit shown in the form of an annular core 17 , on which the windings W2 and W3 are also located. The load 5 is connected via the latter windings to the conductors 7 and 8, which for their part during normal operation are connected to the phase line 1 and the zero line 2 on the main line 3 via the leakage circuit breaker 4, which is closed in that case. As long as there is no significant leakage to ground, the winding on the ground leakage detector will not reveal any imbalance between the windings W2 and W ^ which can be considered as primary windings. As soon as there is a leakage current to ground, an imbalance between the number of amp windings in the windings W2 and W3 will cause such a change in the magnetization state of the core 7 that the electronic unit 16 will be activated via the winding to open the leakage switch 4. The electronic unit 16 and more generally the detector for leakage currents to ground 6 may be of any desired suitable type, e.g. as described in the applicant's older Dutch application 76.07752. Since the construction and operation of components 6 and 16 are not part of the invention, they will be explained only through the above brief description.

Before describing the diagram of FIG. 2, it should be emphasized that the above-described activation of the electronic unit 16 via the winding can be caused not only by an imbalance between the number of amp windings in the windings W2 and W1, but also by the introduction of a number of fault situation amp windings via an extra winding W4 as shown in the circuit diagram of FIG. 2. This point will be discussed later.

The locations where the zero wire 2 on the main wire 3 and the ground electrode 9 on the installation 5 are grounded are in FIG. 1 denoted by 18 and 19 respectively.

It will be clear from the foregoing that the functional apparatus associated with the electrical apparatus 5 and acting as a ground leakage detector in the described embodiment may be considered more generally as a security system. A security system of this kind usually requires a smaller energy supply and is normally fed from the available AC mains. In the described embodiment, this is done by means of the energy supply 10, whose first and second terminals 11 and 12 are connected respectively to wires 7 and 8 and the leakage circuit breaker 4 to the phase and the neutral wire 1 and 2 respectively on the AC mains 3.

If there is an interruption of the zero wire 2, e.g. at 20, not only the supply to the electrical installation 5 via the wires 7 and 8 will be interrupted, but also the supply of energy to the unit 10 via the terminals 11 and 12, so that the entire security system 6 will cease to function, and this must be considered a disadvantage. .

The circuit of FIG. 1 addresses this disadvantage. IN

In the above-described situation where an interruption occurs at 20 in the zero line 2 in the power supply, the conductor 8 will assume a considerable potential, which can be as large as the potential of the phase line 1, via the electrical installation 5, which then no longer bears the normal operating current and the conductor 7 connected to the phase line 1. Further, as already mentioned, the earth electrode 9 is connected to the electrical installation 5 and in practical use it can be regarded as having a neutral potential, ie. the original potential of the leader 8.

In this circuit, this phenomenon is utilized by supplying the power supply 10 not only to the first and second terminals 11 and 12 connected to the conductors 7 and 8, but to a third terminal 13 connected to the ground electrode in such a way that interrupting in the zero line 2, the current supplied to the energy supply 10 continues via the terminals 12 and 13, ie. via the ground electrode. The details of the power supply 10 for this purpose will be explained in more detail below with reference to drawings 3A, 3B and 3C.

First, the above-described design according to the invention enables the ground leakage detector 6 and, more generally, the safety system to continue to operate even in the event of a power line interruption. In this case, the supply, which usually requires very little energy, takes place via the ground electrode 9 of the electrical installation 5.

Furthermore, the design according to the invention allows a voltage increase on the neutral wire 2 to be signaled or used for triggering the security system, even if the voltage on the phase has disappeared. For this purpose, reference is made to the diagram of FIG. 2, which corresponds in practically every detail (except the winding W 1) to the diagram of FIG. 1 so that the relevant components have the same reference numerals as in FIG. First

Referring to FIG. 2, the third terminal 13 of the energy supply circuit 10 has no direct connection to the earth electrode 9, as in FIG. 1, but connection via the winding on the ground leakage current detector. A sudden increase in current through the earth electrode 9 is introduced into the detector 6 for leakage currents to ground via the winding W4 as an information source.

The resulting change in the magnetization state of the core 17 causes the ground leakage current detector to open the leakage circuit contact 4 so that no voltage is applied to the installation. No further details should be mentioned in connection with further signaling of this phenomenon.

However, it should be emphasized that the use of a winding W4 coupled to the core 17 and located in the connection between the third terminal 13 of the power supply 10 on the one hand and the ground electrode on the other hand is only one example of the introduction of specific information on abnormal states, in this case, information regarding wiring failures in the safety device 6. Of course, other fault situation information can also be entered in the security system in a similar or similar manner. In the embodiments of FIG. 1 and 2 e.g. For example, a current increase through third terminal 13 to the ground electrode may be substituted as an information source with the voltage increase between terminals 12 and 13. Those skilled in the art will not find it difficult in practice to select from the available fault situation information and the methods available for introducing it into the terminal. security system. The only important factor is that when the invention is used, even in the event of a failure of the zero wire in the power supply, the security system 6 will continue to operate and offer the possibility of further operation of the security system. This is also the reason for the more general designation of the safety system or detector 6 for ground leakage currents as a "functional apparatus". Devices of this type may also continue to operate, e.g. signals, alarms or functions in any desired other way, even in the event of a break of the power cord.

Certain embodiments of the energy supply circuit 10 according to the invention will be described with reference to FIG.

3A, 3B and 3C. The same reference numerals 11-15 will again be used as the external connections as in FIG. 1 and 2.

FIG. 3A is a circuit diagram of a rectifier circuit operating with half-wave rectification and comprising a series connection of an impedance 21 and a rectifier 22 between the first terminal 11 and the positive supply line 14. The series impedance 21 is used to make a voltage division of the alternating voltage between conductors 7 and 8 so that the required DC voltage is obtained at the output of the energy supply circuit.

In connection with the low power consumption of the security system 6 this can be achieved by means of the series impedance 21. Other components, e.g. a smoothing capacitor is omitted from the rectifier circuit shown in FIG. 3A. The second input terminal 12 of the power supply is connected directly to the output power line 15. If the second terminal 12 assumes the potential of the phase line 1 due to a disconnection of the zero line 2 on the main line as described above, the rectifier effect on the output line 14 is taken over by another series circuit consisting of an impedance. 23 and a rectifier 24 located between the positive supply line 14 on one side and the third terminal on the other side, which is connected to the ground electrode 9 directly in FIG. 1 and via the winding of FIG. 2. The value of the serial impedance 23 is substantially equal to or less than that of the serial impedance 21. It is clear that in the event of a break of the zero wire, the serial circuit 23,24 takes over the function of the serial circuit 21,22.

FIG. 3B shows the circuit diagram of a full-wave rectifier according to the invention. This essentially consists of the parallel connection of two series circuits on each of two alternating rectifiers 25 and 26} 27 and 28. The connection point of the two rectifiers 25 and 26 of the first series circuit is connected via a series impedance 21 'to the first terminal 11 of the power supply. , while the connection point between the two rectifiers 27 and 28 of the second series circuit is connected directly to the second terminal 12 of the power supply. The serial impedance 21 'can be considered equivalent to the serial impedance 21 of the circuit shown in FIG. 3A. The two series circuits are conventionally connected between the output lines 14 and 15. As proposed according to the invention, there is a third series circuit of two rectifiers 9 150056 29 and 30 between the wires 14 and 15 and the connection point between these rectifiers is connected via a series impedance 23 'to the third terminal 13 of the energy supply circuit; This third series circuit containing rectifiers 29 and 30 operates in the same manner as in the case of the rectifier circuits of FIG. 3A, wherein the second terminal 12 of the energy supply circuit reaches the potential of the phase line 1 of the main line as a result of a break of the zero line 2 (via the electrical installation 5). The serial impedance 23 'performs the same role as the serial impedance 23 in the rectifier circuit of FIG. 3A, but on the other hand, it ensures during normal operation that the current flowing through the supply line 15 will be able to find its way or in the main will only find its way via the second terminal 12.

It should be emphasized that although fig. 3A and 3B are for single phase mains only, the invention is not limited thereto. Eg. For example, the phase line 1 of the AC mains 3 can be considered as one of the phase lines of a main line system. For energy supply from a three-phase main line e.g. For example, the energy supply 10 may be provided with three first terminals 11, each arranged for coupling to one of the phase lines on the main line and via a corresponding series impedance to a bridge circuit for three-phase rectification of conventional type. A rectifier circuit of this type is not shown in the drawings, but can also be constructed in accordance with the requirements of the invention. The only important factor is that, in the event of a break in the zero-wire, the energy supply according to the invention, where the functions of first and second terminals 11 and 12 are changed to the functions of second and third terminals 12 and 13. It should also be noted that fig. 3A and 3B show power supplies which operate without transformers and which basically consist of rectifiers. However, this should not be considered as a limitation of the invention. Energy supply circuits provided with a transformer or other components not shown in the drawing can generally be placed with a third terminal for interconnection with a possible supply from an earth electrode.

The circuit diagram of FIG. 3C differs from the diagram of 3B only at the location of the series impedance 23 '.

However, this difference is of the utmost importance. As already noted in connection with the discussion of the diagram of FIG. 3B, the presence of series impedance 23 'results in the current flowing through line 14 finding a less satisfactory path to ground via rectifier 30 (FIG. 3B) or 28 (FIG. 3C) connected to impedance 23' than through the other. rectifier 28 (Fig. 3B) or 30 (Fig. 3C) so that the current in question will mainly select the last current path, i.e. in the situation shown in FIG.

3B via the second terminal 12 to the zero line 2 on the main line, but in the situation shown in FIG. 3C via the third terminal 13 to the ground electrode 9.

This last situation, if a localized electrode current is allowed locally, allows the possibility to signal a possible ground electrode breakage.

Claims (4)

150056 An energy supply circuit for a functional apparatus, in particular a safety apparatus, such as a ground leakage current detector, which apparatus (6) is adapted to be connected to an electrical installation (5) having an earth electrode (9), and provided with the phase and zero wires (2) of an AC network (3), said circuit (10) having a rectifier circuit (21,22,21 ', 25,26,27,28) having a first (11) ), a second (12) and a third (13) terminal serving respectively for phase (1), zero lead (2) in the network (3) and with the ground electrode (9), so that the rectifier circuit is powered by the ground electrode in at least by a break of the zero wire (2) or a wire connecting the zero wire to the rectifier circuit (21,22,21 ', 25.26.27.28), characterized in that the third terminal (13) is connected to said rectifier circuit (21 , 22.211.25.26.27.28) via another rectifier circuit (24,29,30). Circuit according to claim 1, characterized in that a series impedance (23,23 ') is provided either between the third terminal (13) and its associated rectifier circuit (24,29,30) or between the second terminal (12) and its belonging to the rectifier circuit (27.28). A circuit according to claim 1 or 2, in which the rectifier circuit (21, 22) is of a half-wave type and comprises a rectifier element (22), an electrode of which is connected to the first terminal (11) for connection to the phase line (1) in the network ( 3), characterized in that the rectifier element (22) is connected via an additional rectifier element (24) to the third terminal (13) for connection to the earth electrode (9). A circuit according to claim 1 or 2, wherein the rectifier circuit (25-28) is of the full-wave type and comprises a parallel circuit of at least two series circuits of each two alternately operative rectifier elements (25-28), wherein the connection point of the elements of the first series circuit ( 25, 26) is connected to the first terminal (11) for connection to the phase line (1) in the network, and the connection point for the element