WO1987001902A2

WO1987001902A2 - Protective circuit for electric apparatus

Info

Publication number: WO1987001902A2
Application number: PCT/DE1987/000049
Authority: WO
Inventors: Robert Birkmeyer
Original assignee: Robert Birkmeyer
Priority date: 1986-02-10
Filing date: 1987-02-10
Publication date: 1987-04-09
Also published as: EP0293376A1; DE3604118C2; WO1987001902A3; AU7023487A; DE3604118A1; JPH01501516A

Abstract

A protective circuit for electrical apparatus has an insulated safety line (4) extending from the relevant electrical apparatus (6) to the protective circuit (2). The safety line (4) has inside the apparatus (6) at least one non-insulated region which is not in contact with the current-carrying parts. A first switching device (R1) connected to the safety line (4) and to a reference potential, as well as a second switching device (2) actuated by the first switching device (R1) are arranged between the phase- (10) and neutral- (12) conductors of the electrical path supply of the apparatus (6) and separate, in the activated switching state, the apparatus (6) from the phase (10)- and neutral- (12) conductors. The second switching device (R2) is connected with the phase- (10) and neutral- (12) conductors in such a way that it remains in the activated switching state after having been activated by the first switching device (R1).

Description

Protection circuit for electrical devices

The invention relates to a protective circuit for both people and devices.

All households are now equipped with electrical fuses that prevent the power supply lines from being overloaded and, for example, interrupt the power supply in the event of a short circuit. If a connected electrical device, such as a hair dryer, is placed in the water, e.g. falls into a full bathtub, sink or bucket, this results in a current which is so little increased compared to the conditions in air that normal household security is not triggered.

In some households, so-called fault current protection circuits are installed which have a circuit breaker that triggers, i.e. the voltage supply switches off as soon as a fault current flowing beyond a certain selected value flows over earthed parts outside the operating circuit.

However, such protective circuits cannot avoid all electrical accidents. A fault current protection scarf - Tung does not respond, for example, if a device with only a two-wire connection, that is to say without a so-called protective contact, falls into a water bucket or into a grounded, water-filled bathtub, which has a plastic drainage system. Due to the good insulation effect of the enamel, only a small current flows through the earthed bath tub that this is not covered by the usual residual current protection circuits; therefore, the voltage supply 9 ^and 9 are not switched off.

This means that people who are in the bathtub or who are trying to get the plugged-in device out of the filled bathtub or a water bucket are at risk.

People and devices are also at risk from the fact that errors can occur in the supply network. For example, the protective conductor, but also one or all phases or neutral conductors, can be interrupted. It is also possible that overvoltages occur on the lines due to technical faults in the network or due to connection faults. As a result, malfunctions and malfunctions can occur in connected devices, which not only damage the devices, but also endanger persons handling the devices.

It is therefore an object of the invention to provide a protective circuit which rules out the risk to persons and / or equipment.

The object is achieved in a protective circuit of the type mentioned above in that a safety line running between the associated electrical device and the protective circuit is provided, the safety line in the interior of the device at least one - 3 -

does not touch live, non-insulated area. In addition, a first switching device connected to the safety line and a reference potential and finally a second switching device which can be actuated by the first switching device and which is located between the phase and neutral conductor of the electrical voltage supply of the device and which, when activated, the associated device from phase and Neutral separates. The second circuit device is connected to the phase and to the neutral conductor in such a way that it remains in the activated switching state after activation by the first switching device. So-called self-holding of the second switching device is provided, by means of which the associated device remains switched off after the protective circuit has been triggered once.

In a particularly preferred exemplary embodiment, the protective circuit is accommodated in the housing of the plug of the associated device which serves for the voltage supply. This has the advantage that the user of the device is optimally protected against electrical accidents regardless of the circumstances of the respective house connection, because wherever he uses his device, the protective circuit can come into operation and, if necessary, switch off the power supply to the device.

The structure of the protective circuit is chosen so that the function of existing fuses and residual current protective circuits is in no way impaired. Thus, only additional safety for the user of electrical devices is achieved, without reducing the effectiveness of existing protective devices. _ ix _

In a further exemplary embodiment, a protective circuit is provided with only one switching device designed as a relay, which can also be accommodated in the plug of the associated device, but takes up less space. Otherwise, the working principle is similar to the above. Embodiment.

In a further embodiment, the self-holding of the switching device in the second, activated switching state is achieved by ensuring that the switching device is supplied with voltage via a transformer located between the phase and neutral conductor.

This task is performed with a protective circuit of the above. Kind also solved in that at least one device is provided for detecting the voltages and / or currents present in the voltage supply of the electrical device.

In a particularly preferred exemplary embodiment of the protective circuit, the voltages between the at least one phase and the neutral conductor and the protective conductor, but also the voltage present between the protective conductor and the neutral conductor, are detected and the mains voltage is then only transmitted directly or via a switching element for delivery to the electrical device an at least one switching device is switched on if none of the lines is interrupted and there are no overvoltages on any of the lines. This ensures that the connected electrical device is only connected to the voltage supply when there are no network errors. This prevents ^" dangers to people and / or devices ^" .

A particularly preferred embodiment of the protective circuit has a summation converter, the Windings of the at least one phase, which are assigned to the neutral conductor and the protective conductor, and which have at least one device which impresses a defined current into the sum converter, and a switching element which can be controlled by and through which the magnetic field generated in the summation converter the electrical device can be connected to the voltage supply

The impressed current creates a magnetic field which moves the switching element into a first position in which the electrical device is connected to the voltage supply. The defined, impressed current can only flow if the at least one phase and the neutral are in order. In the event of undervoltage, the magnetic field is not sufficient to move the switching element to the first position. In the event of overvoltages and fault currents, the magnetic field is so large that the switching element is brought into a second position in which the voltage supply to the connected electrical device is interrupted. The switching element is preferably designed in such a way that it is locked in the second position, so that after an overvoltage or a fault current occurs, the device can be accidentally switched on again and thus no danger to persons or the device.

Further embodiments of the invention are characterized in the sub-claims.

The invention is explained in more detail below with reference to the drawings showing exemplary embodiments. , Show it: - 6 -

1: a first exemplary embodiment of a protective circuit in which an existing protective contact is used to obtain a reference potential;

2 shows a second exemplary embodiment of the protective circuit in which the neutral conductor is used to obtain a reference potential;

3 shows a third exemplary embodiment of the protective circuit in which the phase is used to obtain a reference potential;

4: a fourth exemplary embodiment of the protective circuit, which is equipped with only one switching device, and

Fig. 5: a fifth. Embodiment of the personal protection circuit, in which the switching device is supplied via a transformer in the second activated switching state.

Further figures and exemplary embodiments are discussed below.

All figures show the protective circuit in a first, inactivated switching state.

1 shows a protective circuit 2 with a first switching device R1 designed as a relay, the switching coil of which is connected on the one hand via a safety line 4 to the associated device 6, which is only illustrated, and on the other hand to a reference potential at the switching point 8 and via this to the protective contact 20. The security line 4 ends inside -1-

ren of the device 6 and has at least one bare, uninsulated area in the vicinity of live parts, such as the motor or the heating wires of a hair dryer, without touching them. If the device 6 connected to the voltage supply, that is to say the household network, then falls into the water, a current flows from the phase 10 in the device via the water to the safety line 4 and via the coil of the first switching device R1 to the switching point 8 and on Protective contact 20. This current also flows when the device 6 is switched off by a switch attached to the device housing. The relay Rl then picks up and actuates the associated shifter contact sl.

As a result, the second switching device R2, which is also designed as a relay and is located between the phase 10 and the neutral conductor 12, is actuated. The second sound device R2 has three contacts, a contact Schließ¬ s2 and ^'two normally closed contacts OE21 or Ö22. When the relay R2 is actuated via the relay R1, the make contact s2 closes, so that the relay R2 is connected to the phase 10 and the neutral conductor 12 and activates itself. In this way, the second switching device R2 is held in position. At the same time, the NC contacts Ö21 and Ö22 are actuated and the voltage supply to the device 6 is interrupted. The person operating the device is thus immediately protected against the influence of voltage or current.

Because the voltage supply to the device 6 is interrupted, the relay R1 also drops out, the closing contact S1 no longer opens and actuates the relay R2. Due to the self-holding via the closing contact s2, the relay R2 remains in the second, activated switching state and thus ensures that the device 6 remains switched off. Two further circuit versions are shown in FIGS. 2 and 3.

In the absence of a protective conductor 20, or in order to avoid wiring of the protective conductor 20, phase 10 (cf. FIG. 2) or neutral conductor 12 (cf. FIG. 3) can also be selected as the reference potential of the first switching device R1. The coil of the first switching device R1 must be connected to the break contacts Ö21 or Ö22 of the relay R2 in such a way that the relay R1 is de-energized when the second switching device R2 is activated. That Instead of switching point 8, the coil of relay R1 can then be connected to phase 10 (see FIG. 2) via switching point 14 or to neutral conductor 12 (see FIG. 3) via switching point 16.

If the device 6 with the circuitry according to FIG. 2 falls into the water, a current flows through the phase 10, the switching point 14 to the first switching device R1, via the safety line 4 into the device 6 and through the water to the neutral conductor 12 in the device 6, so that the first switching device R1 is actuated and the voltage supply is switched off via the second switching device R2 through its break contacts Ö21 and Ö22.

If the device 6 falls into the water with the circuit according to FIG. 3, a current flows into the device 6 via the phase 10, via the water in the device 6 and the safety line 4 into the first switching device R1 and on to the switching point 16 in the neutral conductor 12. As a result, the first switching device R1 and thus also the second switching device R2 are actuated and the power supply to the device 6 is switched off. The circuits according to FIGS. 2 and 3 enable optimum personal protection against electrical accidents even in the cases in which the house connections do not provide a protective contact or in which the protective contact should not be connected.

The latching of the second switching device R2 can - as shown in Figures 1 to 3 - be designed so that the associated device 6 remains switched off until the power supply to the protective circuit 2 is interrupted.

The protective circuit is preferably accommodated in the housing 24 of the plug 18 of the associated device 6 which serves for the voltage supply.

In the circuit versions shown, the protective circuit 2 switches the associated device 6 off until the plug 18 is pulled out of the socket due to the self-holding of the second circuit device R2.

However, it is also possible to use a special switching device which — possibly mechanically — is also kept in the activated switching state when the plug 18 is pulled out, once the first switching device R1 has been actuated. This prevents the wet, possibly damaged device from being put into operation again.

FIG. 4 shows a further exemplary embodiment of the protective circuit 2, in which the same parts are identified with the same reference numerals as in FIGS. 1 to 3. In the protective circuit 2 according to FIG. 4, only a single switching device R3 designed as a relay is provided. This embodiment has - HO -

therefore requires less space than the examples shown above and is easier to accommodate in the housing 24 of a plug 18.

The relay R3 shown has three contacts, namely a changeover contact u3 and two break contacts Ö31 and Ö32. If the device 6 gets into the water when plugged in, a current flows in a first, inactivated switching state of the third switching device R3 according to FIG. 4 via phase 10, the water in the device 6 and the safety line 4 as well as the switchover contact u3 into the coil of the third switching device R3 and from there to the neutral conductor 12. The third switching device R3 is brought into its second, activated switching state, the relay R3 picks up. The coil of the relay R3 is then supplied with voltage according to FIG. 4 via a series resistor 22 and the changeover contact u3 and thus remains self-holding in the activated switching state. At the same time, the associated break contacts Ö31 and Ö32 are actuated and the device 6 is disconnected from the voltage supply via the phase 10 and the neutral conductor 12. Due to the self-holding, the relay R3 remains in the activated switching state as long as its voltage supply is maintained via the changeover contact u3. When the plug 18 is pulled out, the relay R3 drops out and returns to the first, deactivated switching state,

However, the switching device R3 can also be designed such that it is kept mechanically in the activated switching state, for example, until it is reset by the intervention of a person skilled in the art. This forces the user to take the device 6, which has been switched off by the protective circuit 2, to a specialist who can examine it for damage before resetting the third switching device R3. - -

5, instead of the third switching device R3 shown in FIG. 4, a fourth switching device R4 designed as a relay is provided, which in addition to a changeover contact u4 and two break contacts Ö41 and Ö42 has an additional break contact Ö43 , which separates the relay R4 in the second activated circuit state of the fourth switching device R4 from the neutral conductor 12, and thus prevents a current through the polarity of the plug 18 from a current via the transformer 26 which serves to hold the fourth switching device R4 in the second activated circuit state Water flows. When trying with normal tap water and a hair dryer, the relay R4 - like the relay Rl and R3 - and the transformer 26 are designed for 24V.

In addition, as shown in Fig. 5 nor are the Umschal t-u4 contactless bridging test button 28 is provided, with which the function of Sch ^'utzschal processing can be checked 2 before or during the operation of the associated electrical device 6..

Electronic components such as, for example, thyristors, triacs, and, with the appropriate circuitry, optocouplers or capacitive initiators can also be used without further ado to set up this protective circuit without thereby departing from the scope of the invention.

In any case, the protection circuit 2 prevents the user of an electrical device from being exposed to current or voltage if the device 6 falls into a conductive medium such as water, even if conventional household fuses and residual current protection circuits do not respond. Further exemplary embodiments of the protective circuit are explained in more detail with the aid of the following figures. Show it :

6 shows a further embodiment of the protective circuit according to FIG. Figures 1 to 5, in which the security line is two-wire;

Figure 7 shows an embodiment of the protective circuit in which the supply voltage is checked;

Figure 8 shows an embodiment of the protective circuit in which voltages and currents of the supply network are checked;

FIG. 9 shows an exemplary embodiment of the protective circuit, from which it can be seen how, after the supply network has been checked, it is forwarded to the consumer;

FIG. 10 shows an exemplary embodiment of the protective circuit that responds to a power failure;

FIG. 11 shows an exemplary embodiment of the protective circuit according to FIG. 10 with an additional summation converter;

Figure 12 shows an embodiment of the protective circuit with a bimetal 1 -Off! solution;

FIG. 13 shows an exemplary embodiment of the protective circuit according to FIG. 12 with an integrated summation converter;

FIG. 14 shows an exemplary embodiment of the protective circuit for devices without a protective conductor;

Figure 15 shows an embodiment of the protection circuit with a temperature-dependent resistor; 13

Figure 16 shows an embodiment of the protective circuit with mechanical contact tripping;

Figures 17 to 21 different embodiments of the protection circuit with a summation converter, which is pre-magnetized; and

Figure 22 shows an embodiment of the protective circuit with a summation converter without bias.

Elements that correspond in the figures are provided with identical reference symbols.

The exemplary embodiment shown in FIG. 6 differs from that shown in FIGS. 1 to 5. In the exemplary embodiments explained above, the connected device can also be switched on when the safety line 4 is interrupted. This is not, in the embodiment of Figure 6 are possible: ^~ The electrical device 6 is only the direction by means of a formed here as a relay fifth Schaltein¬ R5 to the phase 10 and neutral 12 ver¬ inhibited when full size also as a relay via a ¬ formed sixth switching device R6 voltage is applied to the fifth switching device R5.

The sixth switching device R6 is connected to phase 10 and neutral conductor 12 via a suitable supply line, in which an isolating transformer can also be provided, and via a rectifier. A capacitor C is provided parallel to the sixth switching device R6 and can be charged to a defined voltage value with a predetermined polarity via resistors 30, 31 provided in the supply line.

The sixth switching device R6 is activated when - f | -

they applied with ^¬ on the Zulei for, or the capacitor C by means of a switching element voltage SCH verbun¬ the will. As a result, the fifth switching device R5 is connected to the voltage supply and activated via a switching contact s6 of the sixth switching device R6 and transmits the mains voltage to the electrical device 6 via suitable switching contacts s51, s52.

At the same time, the capacitor C discharges and the sixth switching device R6 is deactivated again, even when the switching device SCH is closed, or drops off, since the resistors 30 and 31 are selected such that the supply voltage for the sixth switching device drops to one value which is not sufficient for activation. While the sixth switching device R6 is activated, however, in the error-free, i.e. dry state of the electrical device, a current flows through the series resistors 32, 33 and the two wires of the safety line 4 to the sixth switching device R6. The resistors 32, 33 are selected so that the mains voltage is adapted to the supply voltage of the sixth switching element. As a result, the sixth switching device R6 remains in the activated state even when the capacitor C is discharged and the switching element SCH is opened.

However, if water penetrates into the device, non-insulated areas of the safety line 4 running in the device or the indicated sensor pairs 34, 35, 36 are bridged, as a result of which the voltage supplied to the sixth switching device R6 via the safety line 4 breaks down. As a result, the sixth switching device R6 changes to the inactivated state. As a result, the fifth switching device R5 is disconnected from the voltage supply and the voltage supply to the electrical device 6 is interrupted. Any surge protection devices 37, 38 can be provided to protect the sixth circuit device R6.

In the exemplary embodiment shown in FIG. 7, the voltage supplied by the network is checked before switching on to the electrical device or further interposed safety devices.

Known fuses 39, 40, 41, which are provided when the supply voltage enters, for example, a household, are indicated in FIG. 7; the phases are designated R, S, T, the neutral conductor with N and the protective conductor with SL.

By means of suitable devices A, B, C, D the voltages lying between the phases R, S, T and the neutral conductor N are detected. In addition, a device is provided for detecting the voltage lying between the neutral conductor N and the protective conductor SL. In the present case, the devices mentioned are designed as relays provided with break contacts a, b, c, d, the break contacts of which are arranged in the supply line of a switching element E. As soon as the response voltage of the devices for detecting the voltages, which is matched to the respective measuring points, is exceeded, the supply line of the switching element E is interrupted. The switching element E is also designed here as a relay with five Schi i eß contacts el, e2, e3, e4, e5. Instead of the relays, other components can also be used.

Additional voltage detection can be carried out between the individual phases and between the phases and the protective conductor I devices are provided. The normally closed contacts of these devices, which are also designed as relays, for example, are then likewise arranged in the supply line of the switching element E.

The dashed line indicates that the voltage between the phases and the protective conductor can also be detected.

With this construction it can be achieved that in the event of overvoltages occurring at the phases or between the neutral conductor and the protective conductor, the supply line of the switching element is interrupted and thus the voltage supply to subsequent consumers is also interrupted.

The relays which are arranged on the phases respond, for example, to voltages of 350 volts and more, the relay located between the protective conductor and neutral conductor to voltages of, for example, 60 volts.

The individual devices for detecting voltages can be supplied by overvoltage protection devices U1, U2, U3, U4.

In FIG. 8, an embodiment of the protective circuit is shown, which voltages and currents that are generated by the protective circuit according to FIG. 8 are switched on, monitored or checked. The exemplary embodiment can also be used to directly monitor or check the line voltages.

The voltages present between the phases R, S, T and neutral conductor N or protective conductor SL and the voltage are determined by suitable devices R7 to R1 between protective conductor SL and neutral conductor N detected. The devices here are also designed as relays, but any other switching units that respond to specific voltages can also be used.

The relays are designed so that they only respond at a certain minimum voltage. All relays are assigned to a switching element described below with reference to FIG. 9, which forwards the line voltage to electrical consumers directly or via at least one switching device. The minimum voltages of relays R7, R9, R11, R13, R14, R15 are approximately 180 volts, those of relays R8, RIO are approximately 270 volts and those of relay R12 are approximately 60 volts. If required, other voltage values can also be selected.

This ensures that a minimum voltage is present at the phases for switching on the supply voltage, while at a maximum voltage of approx. 60 volts between the neutral conductor and the protective conductor, the switching element used for switching on remains deactivated or is deactivated.

FIG. 8 also shows a total current converter that includes all the lines of the supply network. All currents, including capacitive parts, even those on the protection! ei ter ^'bewi strengths no signal at the summation transformer. Rather, this only responds to currents that flow out of the operating system or the operating circuit.

Each current flowing out of the operating circuit induces a voltage in the coil 42, which in the present case is protected against damage by overvoltages by an overvoltage protection device. The i

Voltage is rectified in a rectifier Gl and charges a capacitor Cl, which discharges through an adjustable resistor 43. With the adjustable resistor 43, the charging time constant of the

5 capacitor C1 and thus also the level of the fault current at which a switching device R16 responds. The circuit device is resolved here via a switching element designed as a Zener diode ZD1. If the fault current

¹⁰ Zener voltage is reached, a current flows through the switching device R16, which is designed as a relay, the contact of which is assigned to the switching element shown in FIG.

From FIG. 8 it can be seen that the phase R the current flowing through the line is detected in a known manner by means of a defined resistor or by means of a coil. The voltage based on the current is rectified in a rectifier G2

2 ° and charges a capacitor C2, the charging current of which can be set via an adjustable resistor 44 and / or a parallel-connected resistor 45. By resistors this Überstromerfassungsei can nri ch tung adapted to different conductor cross-sections advertising ⁵ to. The voltage across the capacitor C2 can activate a switching element, which is designed here as a Zener diode ZD2. When the Zener voltage is reached, the Zener diode ZD2 switches through and activates a switching device R17, which is designed, for example, as relay 0 and has a contact assigned to the switching element shown in FIG.

When the current flowing through the line R exceeds a value predetermined by means of the adjustable resistor 44 and by the choice of the Zener diode ZD2, the switching device R17 is activated and interrupt the power supply to the consumer.

Dashed lines are used to indicate that an overcurrent detection device of the type just described can be assigned to each of the lines. To avoid overvoltages, an overvoltage protection device 46 can be assigned to each overcurrent detection device.

A particular advantage of this overcurrent detection device is that by suitably adjusting the adjustable resistor 44 and selecting the resistor 45 and the Zener diode ZD2 appropriately, overcurrents can be detected which are a factor of 1, 5 and less than a desired value.

From Figure 8 is also a Überwaehungsei device that detects the failure of a phase or a short circuit between the conductors. A switching device R18 is connected to the phases on the one hand via any consumers 47, 48, 49 which are the same as one another and on the other hand to the neutral conductor N. The dashed line indicates that a connection to the protective conductor can also be provided.

The same consumers create an artificial zero point, which no longer exists if there is a short circuit or short circuit or one of the phases fails. When the potential present at the connection point of the consumer shifts, the switching device R18 is activated, which is designed here as a relay which has at least one contact which is assigned to the switching element shown in FIG. FIG. 9 shows a switching element which interacts with the safety devices described above with reference to FIG. 8 and which switches the line voltage on to a consumer if the check of the network has shown that on the one hand there are no overvoltages and currents but on the other hand certain minimum voltages are.

In the present case, the switching element has two interacting relays R19, R20. However, other switching units can also be used.

A first relay Rl 9 has five make contacts s191 to s195. It is connected via a first line to the neutral conductor N and a second line, for example to the phase R. In one of the lines, here in the first line, contacts of the switching devices or relays described above are arranged in series, namely the make contacts s7, s8, s9, slO, sll, s! 3, sl 4, s! 5. They thus form an AND circuit.

If the associated relays R7, R8, R9, RIO, Rll, R13, R14, R15 have a minimum voltage above the response voltage, these make contacts are closed. The first relay R19 is thus connected to the voltage supply and changes to the activated state; i.e. the lines of the supply network are connected to the consumer.

If overvoltages or overcurrents occur in the supply network, the corresponding switching devices R12, R16, R17, Rl 8 described above are activated, ie the associated contacts s! 2, s! 6, s! 7, s18 closed. This leads to the fact that a direction serving second relay R20 with the voltage supply, here with the phase R and the neutral conductor N is connected. The make contacts of the relays Rl2, Rl6, Rl7, Rl 8 are connected in parallel and form an OR circuit. In addition to the contacts, a test button P paral! be switched with which the function of the circuit can be checked.

The second relay R20 has a locking device 50 which holds the second relay in its activated position when an overvoltage or an overcurrent has led to the activation of this switching device. This avoids that the mains voltage can be switched on accidentally after an error has occurred, which can lead to faults in the connected consumer and to the persons handling it.

In the present case, the second relay 20 of the switching element is provided with two break contacts Ö201, Ö202, one of which controls a control lamp K in the event of a fault, which indicates a fault, while the other deactivates the first relay 19.

FIG. 9 also shows a display device Z which is connected to the supply network, for example via a transformer T. The display device can have known optical and / or acoustic display instruments which can be switched using the switching devices or relays described in FIGS. 7 to 9. As a result, the switching state of the protective circuit can be monitored by an operator by means of a display device Z which is also arranged at a distance from the protective circuit. In this way it can be represented whether the

Checking the supply network, errors have been found or which errors have occurred. FIG. 10 shows an exemplary embodiment of the protective circuit, in which the safety circuit according to FIG. Figure 7 forwarded voltage checked and, if necessary, to the consumer, the electrical device is forwarded. The circuit according to FIG. 10 can, for example, also be connected directly to the supply network via plug contacts with the switching device according to FIG. 7.

The safety device has a selector switch W, by means of which the phase R, S or T to be connected can be freely selected.

The current flowing on the line from the selector switch W to the electrical device is detected by an overcurrent detection device which is explained in more detail with reference to FIG. 8, and in the event of an overcurrent a first switching device R21 is activated in the manner described above. The first. Switching device R21 has a make contact s21, which is assigned to a second switching device R22 so that it is also activated when the first switching device R21 is activated. As a result, the associated break contact Ö22 of the second switching device R22 is opened and a third switching device R23 of. the voltage supply via phase and neutral is separated. The third switching device R23 is provided with the lines of the supply network, ie with phase contacts, neutral conductors and protective conductors, with make contacts s231, s232, s233 which, when the third switching device R23 is activated, connect the supply network and the consumer 6 or a socket.

A fourth switching device R24 serves to mechanically lock the third switching device R23 in the closed position. hold its position during which the voltage supply is interrupted by the normally closed contact ö24 of the fourth switching device R24 in order to save energy in the activated state. The fourth switching device R24 is deactivated in the event of a fault or in the event of a phase or neutral failure, as a result of which the third switching device R23 likewise changes to the deactivated state.

When triggered in the event of a fault, the second switching device R22 is locked via a locking device, so that the associated device 6 remains switched off.

All switching devices are shown here as relays, but any other switching devices can also be used.

FIG. 11 shows a further exemplary embodiment of the protective circuit according to FIG. 10. Corresponding parts are provided with the same reference symbols and will not be explained further.

The exemplary embodiment shown likewise has a selector switch W and an overcurrent detection device assigned to the phase with a first switching device R25. The function of this device was explained in detail with reference to FIG. 8. A further overcurrent detection device with a second switching device R26 is assigned to the protective conductor SL. The overcurrent detection devices are through

Surge protection devices ül, Ü2 protected against overvoltages.

A summation converter, the function of which was also explained in detail with reference to FIG. 8, detects the protective conductor in addition to the phase and neutral conductor. It will therefore only currents leaving the operating system are detected by the summation converter and a third switching device R27 is activated. Several devices are provided for detecting voltages, specifically for detecting the voltage between phase and neutral conductor, between phase and protective conductor, and the voltage present between protective conductor and neutral conductor. In the present case, relays are selected for detecting the voltage, the response voltages being matched to the respective measuring points, as described above.

If the necessary voltages are present between the phase and the neutral conductor or protective conductor, it is ensured that the voltage is present on the phase and that neither the neutral conductor nor the protective conductor are interrupted.

This activates the relay R28 located between the phase and neutral conductor and the relay R29 located between the phase and protective conductor and activates a fourth switching device R30, which is also designed as a relay. The make contacts s28, s29 assigned to relays R28 and R29 are in the supply line to relay R30. The consumer or a socket is connected to the mains voltage by the three make contacts s301, s302, s303 of the fourth switching device R30.

If an overcurrent is detected on the line or the protective conductor assigned to the phase, a fault current from the summation converter or an overvoltage between protective conductor and neutral conductor from the fifth switching device R31, the corresponding relays R25, R26, R27, R31 activated. The relays point in parallel! The switched closing contacts s25, s26, s27, s31, which are combined to form an OR circuit. So when one of the relays is activated, a sixth connected to the OR circuit becomes Switching device R32 activated. This has an NC contact Ö32 in the supply line to the fourth switching device R30. As a result, when the sixth switching device R32 is activated, the fourth switching device R30 is brought into the deactivated state.

FIG. 11 shows a locking unit V, which locks the sixth switching device R32 in the activated state, so that an inadvertent switching on of the electrical device after an error occurs is precluded and thus a danger to the device and the persons handling it is excluded becomes.

The response voltage of the fifth switching device R31 can be, for example, at 25 volts and the response current of the overcurrent detection device of the safety conductor e.g. are between 0.1 and 100 mA.

FIG. 12 shows an exemplary embodiment of a security device for supply networks without a protective conductor. In this case, the protective conductor running to the consumer or to the socket is connected to the neutral conductor of the supply network. In the one used by the electrical device as the protective conductor

Line is an overcurrent detection device designed as a bimetal 1 switch B, for example, which switches a switching device R. This connects the electrical device 6 to the supply network via three make contacts rl, r2, r3. If an overcurrent flows through the metal switch B, the heating opens both a first contact bl of the bimetal switch B located in the protective line SL of the device and a contact b2 located in the supply line to the switching element R. As a result, the switching device R is deactivated and the electrical consumer from the network - 2.6 -

Cut .

The connection between the supply network and the consumer is also interrupted by the switching device R if the phase labeled Ll fails.

In the present case, a locking device V is provided which locks the contact b2 in the open position, so that an accidental switch-on of the connected device is impossible after an error or an overcurrent has occurred.

The switching device R is designed as a relay; however, any other switching devices can also be used.

The safety device acc. Figure 12 can be accommodated in an adapter housing.

FIG. 13 shows an exemplary embodiment of the protective circuit with a summation converter S, which monitors the phase designated as L1 and the neutral conductor N, with a first switching device R32. The sum converter S is shown in simplified form. For example, it can have the structure shown in FIG. 8 and explained with reference to this figure. Here, too, the protective conductor could be connected to the neutral conductor (dashed line).

A second switching device R33 detects the voltage present across phase and protective conductor SL and is activated at a specific response voltage of 180 V, for example. As a result, the associated closing contact s33 is closed and a third switching device R34 is connected to the phase L1 and the neutral conductor N and activated. Their closing contact s34 connects with it _r - 27 -

a fourth switching device R35 with phase and neutral and activates it. As a result, the connection between the mains supply and the consumer is finally closed via their make contacts s351, s352, s353.

A e.g. Overcurrent detection device designed as a bimetal switch B detects a current flowing on the safety conductor SL. The protective conductor is interrupted by the heating of the first contact bl of the bimetal switch B in the event of an overcurrent.

Instead or simultaneously, a second contact b2 of the bimetal 1 switch B is closed.

In the event of a fault current, i.e. in the event of a current flowing against the environment or via the protective conductor, the summation current transformer or summation transformer S responds, i.e. the first switching device R32 is activated and its make contact s32 is closed.

The second contact b2 and the make contact s32 are connected in parallel and form an OR circuit in the network connection of a fifth switching device R36, which is activated whenever one of the two contacts or both are closed. In this case, an NC contact Ö36 in the supply line to the fourth switching device R35 is opened and its connection to the network is disconnected. As a result, the fourth switching device R35 enters the deactivated state and disconnects the consumer from the mains.

The switching device R36 can be held in the activated state by a locking device V until it is unlocked, for example by a specialist, in order to prevent the device from being inadvertently switched on again. This will endanger the

Device and the people handling it excluded. All switching devices are designed as relays at game shaft. However, other switching devices can also be used.

In the description it was assumed that the lines leading from the protective circuit lead directly into an electrical device. But it is also easily possible to lead them to a socket or other switching elements for electrical devices

The embodiment according to. FIG. 14 is designed for devices with protective insulation, that is to say without a protective conductor, and / or for galvanically isolated networks. In this case, in order to increase safety, a separating device designed as an isolating transformer T is provided, which galvanically separates the connected electrical device 6 from the mains supply and, for example, forms two phases L1 and L2. Connected to the supply lines L1 and L2 of the electrical device 6 are any consumers 51, 52 of the same type which are connected to one another to form an artificial difference or zero 1 on the side opposite the supply lines. At least one of the two consumers can also be designed to be tunable.

At the connection point, a first switching device R 37 is connected to a first connection, the second connection of which is connected to a safety line 4 which has at least one non-insulated area in the device 6 which carries near-current parts.

A test button P is provided which connects the safety line 4 with the supply lines L1 and / or L2 and which can be used to simulate a fault and to test the function of the protective circuit. The electrical connection between the network or the isolating transformer T and the device 6 is established with the aid of a second switching device R38 having two make contacts s381, s382, which is connected to the network or the isolating transformer T via a connecting line. An NC contact Ö37 of the first switching device R37 is provided in the connecting line.

If phase (s) fails or the supply lines to device 6 are short-circuited, the potential existing at the connection point of consumers 51 and 52 is shifted and the first switching device R37 is activated. This also opens their NC contact Ö37 and disconnects the second switching device R38 from the power supply, i.e. deactivated. This also disconnects the device 6 from the network.

A locking device V can be connected to the first switching device R37, which prevents the device 6 from being inadvertently switched on again after an error has occurred. The locking device V can also be designed such that it has a reset button, not shown here, which is operatively connected to the break contact Ö37 and / or a break contact liegenden located in the safety line 4 such that the protective circuit only supplies voltage to the Device emits itself if the protective function is ensured.

Here, too, the switching devices are shown as relays, but other switching devices can also be formed.

FIG. 15 shows an exemplary embodiment of a protective circuit having a temperature resistance R. This can have a negative temperature coefficient (NTC) or a positive temperature coefficient (PTC).

The resistor R is arranged in the protective line SL. Between phase Ph and neutral conductor N there is a first switching device R39, which connects a consumer or a socket to the supply network via three suitable make contacts s391, s392, s393.

A second switching device R40 with an NC contact Ö40 in the supply line of the first switching device R39 lies between the protective conductor SL and neutral conductor N.

If a current occurs on the protective conductor and a voltage drops across the resistor R, the second switching device R40 responds and interrupts the supply to the first switching device R39; this is deactivated, so that the associated socket or a connected consumer is disconnected from the supply voltage.

If the resistor R is designed as an NTC, a voltage builds up on the protective conductor immediately after the occurrence of a current, which voltage increases with increasing

Warming decreases due to the falling resistance value. This means that the second switching element R40 can trip immediately and disconnect from the mains. If the second switching device R40 is defective, upstream safety devices can take over the shutdown due to the current flowing on the protective conductor SL.

If the resistor R is in the form of a PTC, the resistance value of the resistor is initially low in the case of a current flowing on the protective conductor, that is to say the falling voltage. The protection circuit Upstream safety devices should therefore switch off the mains supply. In the event of a defect, however, the current flows on the protective conductor until an increase in resistance due to the heating of the PCT occurs and a higher voltage across resistor R drops. When this reaches the response voltage of the second switching device R40, it responds and disconnects the defective consumer from the voltage supply.

The second switching device can be provided with a locking device V which prevents inadvertent switching on after an error has occurred.

Here too, other components can be used as switching devices instead of the relays shown at spi el shaft.

FIG. 16 shows an exemplary embodiment of the protective circuit in which the disconnection of the consumer from the mains is triggered by a mechanically actuable switching element that responds to moisture.

The electrical device 6 is connected to the supply voltage via at least two contacts oil, 02 which are under mechanical pretension and which are accommodated in a waterproof housing G. The bias is preferably generated by a first tension spring ZI. The contacts oil, b ^' 2 are held in the closed position by a locking element V. The locking element is rotatably mounted about a swivel joint D. A holding arm H attached to the housing G holds a prestressed, moisture-sensitive element S3, for example a paper strip, which is connected to the locking element V via a connecting member 54. The link 54 will - 32 -

For example, a membrane or by a water-conducting solid ^¬ 'in the casing G to the lung Verriege¬ element V out. The holding arm can be omitted if the housing G or the parts contained therein and the element S3 are anchored in the associated electrical device 6.

The moisture-sensitive element 53 and the second tension spring Z2 are matched to one another in such a way that the locking element V is held in the position shown in FIG. 16 and the contacts ^" d1 and 02 are closed. When the element 53 becomes damp, its tensioning force decreases , the tensile force of the tension spring Z2 predominates and turns the locking element V counterclockwise, so that the contacts oil and 02 are released. Due to their pretensioning, they move into the open position and thus separate the connected consumer from the supply voltage,

When changing the point of engagement of the connecting element 54 on the locking element V, a moisture-sensitive element can also be used, the tensile force of which increases when exposed to moisture, so that the locking element V is rotated counterclockwise.

FIGS. 17 to 22 show exemplary embodiments of the protective circuit in which at least one summation converter or one summation jump converter is used in each case.

In the embodiment according to. FIG. 17, the summation converter has three windings which correspond to the phase denoted by L1, the. Neutral conductor N or the protective conductor SL are assigned. The windings assigned to the neutral conductor or the phase are designed, for example I wrapped bifilar that the magnetic fields arising from the currents cancel each other out. A defined current and thus a specific magnetic field is impressed on the sum converter via a resistor 55, which is connected to the phase on the network side of the sum converter and to the neutral conductor on the consumer side of the sum converter. This leads to a switching element 57, which responds to magnetic fields, being triggered. Here, a switching element 57, which is rotatably mounted about an axis 56, is deflected from a basic position by the magnetic field and brought into a first position. This closes a make contact s57. This is in a supply line of a first switching device R41 located between phase and neutral with three make contacts s411, s412, s413, via which a socket or a consumer 6 can be connected to the supply network.

If the defined current flows, the switching element 57 is deflected such that the first switching device R41 is activated and the connection between the network and the consumer is established. If the phase fails, the impressed current and thus the defined magnetic field are also eliminated, so that the switching element 57 is not deflected and the connection between the network and the consumer is or remains disconnected.

If a current flows into the environment via the supply lines, the magnetic fields which arise in the windings associated with the phase and the neutral conductor do not cancel each other out and the switching element 57 is moved from the first position determined by the impressed current and into a second position brought. As a result, the voltage supply to the first switching device ^■ 1 I - 34 - ^!

device R41 and thus the connection between the network and the consumer is interrupted.

The same applies in the event that current flows through the protective conductor SL due to a defect, as a result of which a magnetic field is generated in the winding associated with the protective conductor.

In the de-energized state, the switching element 57 is held in a basic position by a spring F in which the first switching device R41 is separated from the supply voltage and the consumer is therefore not connected to the network.

Using a test button 58, a current flow can be generated via a second resistor 59 which is parallel to the first resistor 55 and which simulates a fault current. The function of the protective circuit can thereby be checked.

Furthermore, the voltage drop across a measuring resistor 60, which is additionally arranged between the protective conductor of the mains supply and the protective conductor of the summation converter, the voltage prevailing at the first resistor 55 and the potential between protective conductor SL and neutral conductor N can be detected . For this purpose, the relays R42, R43, R44 are provided in FIG. However, other devices can also be used. The relays have break contacts Ö42, i Ö43, Ö44, which are located in the supply line of the first switching device R41 and which, with a selectable response voltage, separate the first switching device R41 from the voltage supply and thus the consumer from the mains.

In addition, a locking device V, only sketched here, can be provided, which holds the switching element 57, for example, also the contacts Ö42, Ö43 and / or ö44 until they are unlocked, in the position that occurred in the event of a fault and in which the consumer is disconnected from the mains a risk to the consumer and the people handling it by accidentally switching on is avoided.

The locking element V is designed such that the consumer cannot be connected to the mains voltage during an unlocking attempt. For this purpose, an NC contact is combined with the locking element, which is indicated by a broken line in FIG. 17.

This design means that in the event of undervoltage, overvoltage and fault currents, the consumer cannot be connected to the mains voltage. Various switching properties can be achieved by suitable selection of the measuring resistor 60: If the resistor 60 is chosen to have a low resistance, conventional fault current circuit breakers combined with the protective circuit can implement an immediate mains voltage parallel to the existing protective circuit. If the resistance 60 is dimensioned with a high impedance or if it is destroyed, conventional residual current circuit breakers cannot carry out a mains disconnection. The consumer is also disconnected from the mains due to the voltage applied to relay R42 in the event of a fault. The relay R42 can also be replaced by a pin switching element which becomes low-resistance when voltage is applied and forwards a current to the protective conductor SL. In this way, upstream residual current circuit breakers can separate the mains.

The number of turns of the winding assigned to the safety conductor can also be increased compared to the other windings, so that magnetic fields based on reverse currents are amplified in the summation converter and switching off by deflection of the switching element 57 can take place even at relatively low currents.

FIG. 18 shows an embodiment of the protective circuit which is preferred for protective-insulated devices without a protective conductor.

The sum converter used here, like the one explained in FIG. 17, has a winding assigned to the phase labeled L1 and the neutral conductor N, the winding direction of which is selected such that the magnetic fields created by the currents on the phase and neutral conductor are mutually exclusive cancel. A third winding is assigned to a safety line 4, which runs from the connected consumer 6 or a socket via the summation converter, a resistor 62 to the neutral conductor N. A connection to phase L1 can also be provided instead. As in the exemplary embodiments described above, the safety line 4 has at least one uninsulated area near live parts within the electrical device 6. If there is a conductive connection, for example through water, to live parts, it flows in current limited by the resistor 62 via the safety line 4 and the corresponding winding of the summation converter. The magnetic field thus generated acts via a magnetizable material, for example via an iron core, on a switching element 57 described with reference to FIG. 17, which is rotatably mounted on an axis of rotation 56 and has a make contact s57. The switching element 57 is thereby brought from the first position based on the premagnetization into a second position, in which an assigned first switching device R45, via which with the help of three associated shift contacts s451, s452, s453, the electrical device 6 is connectable to the power supply, is deactivated.

The switching element 57 can be locked in this position by means of a locking device 61 in order to prevent the electrical device 6 from being inadvertently switched on again after an error has occurred.

A spring F holds the switching element 57 in the de-energized state in a basic position in which the first switching device R45 is likewise deactivated and the device is disconnected from the mains.

In order to bring the switching element 57 into a first position, in which the first switching device R 45 is activated and whose contacts s451 to s 53 are closed, the summation converter, as in the exemplary embodiment according to FIG. 17, a defined current is impressed via a resistor 63, which generates a magnetic field which deflects the switching element 57 against the force exerted by the spring F. As a result, the make contact s57 of the switching element _ located in the supply line of the first switching device R45 is closed and the first switching device R45 is activated. - 38 -

In parallel to the resistor 63, a further resistor 64 and a test button 65 can be provided, by means of which a specific fault current can be generated for the functional test of the protective circuit.

Between phase L1 and neutral conductor N there is also a second switching device R46, the closing contact s46 of which is closed in the event of an overvoltage occurring between the lines mentioned, so that the protective circuit is triggered and the electrical device is disconnected from the mains. This takes place in that a current so high flows via the contact s46 and the resistor 64 that the switching organ 57 is brought into the second position by the increased magnetic field, in which the contact s57 is open and the first switching device R45 is deactivated.

Usual fuses 66 and 67 in the supply lines to the summation converter are only hinted at here.

Here, as in all the other exemplary embodiments shown, the safety line 4 can be designed as a so-called screen above the supply lines to the electrical consumer. The use of such shielding cables optimally protects the lines guided in the shielding against external damage.

The switching devices mentioned here can be of any design. The relays are only chosen as examples.

FIG. 19 again shows an exemplary embodiment of the protective circuit with a summation converter which is suitable for protective-insulated devices and has three windings, one of which is connected to the phase denoted by L1, one to the neutral conductor N and one to the safety line 4. is arranged. The latter is connected to the neutral conductor N via a resistor 68 and has uninsulated areas near current-carrying parts within the device 6, which is indicated by a resistor 69. Also provided in the interior of the device is a sensor line 71 which is arranged near the safety line 4 and which leads to the phase via a safety resistor 70 and via which a conductive connection between the phase and the safety line is established, for example when water penetrates into the device and a fault current is generated. The fault current creates a magnetic field in the summing converter, by means of which the switching element 57, which has ferromagnetic material, for example, is moved into the second position, in which an assigned switching element R 47 is deactivated. This opens its closing contacts s471, s472, s473 and disconnects the electrical device from the mains.

The exemplary embodiment shown has a test button 72 with which a function test is carried out and, for example, an interruption in the safety line 4 can be determined.

As described above with reference to FIGS. 17 and 18, a current flowing through a resistor 73 is impressed on the sum converter, which brings the switching element 57 into a position against the force exerted by a spring F, in which the closing contact s57 assigned to the switching element 57 closes is. This is in the supply line to the switching device R47 and activates it.

Here too, a locking device 61 is provided, which locks the switching element 57 in the position assumed in the event of a fault and thus ensures that the switching device R47 is deactivated and the electrical device remains switched off.

It can be seen that, in the exemplary embodiment shown here, the summation converter is designed in such a way that the start-up of the associated device is ruled out in the event of undervoltage, because then the applied magnetic field is not sufficient to bring the switching element 57 into position against the force of the spring F. in which contact s57 is closed. The

Shutdown takes place after everything flowing into the environment and in the case of fault currents flowing on the safety line 4 and in the event of overvoltages, the switching element 57 being locked in the second position.

The locking device 61 is unlocked by actuating the reset button R, which is only indicated here as in the other figures.

Here too, a test button 65 with a series resistor 73 'is provided, by means of which the function of the protective circuit can be checked both with regard to overvoltage shutdown and with regard to fault current shutdown. An overvoltage detection device, not shown here, connected in parallel with test button 65 can, in the case of a selectable overvoltage, allow a fault current to flow, which generates a magnetic field which triggers the protective circuit and switches off the connected electrical device.

FIG. 20 in turn shows an exemplary embodiment of the protective circuit designed for protective-insulated devices with a summation converter whose windings have the phase denoted by L1, the neutral conductor N and the safety device. - 41 -

unit line 4 are assigned. The windings from

The phase and neutral conductor are again arranged in such a way that the resulting magnetic fields cancel each other out.

As in the exemplary embodiments described here, a switching element 57 rotatably mounted on an axis of rotation 56 with or made of ferromagnetic material or the like is shown here. Provided, which can activate a switching device R47 with three make contacts s47l, s472, s473 via an assigned contact s57.

The electrical device 6 is started up by, for example, pressing a button 77 with two make contacts s771, s772 so that a defined current flows through the electrical device 6 and the summation converter. This creates a magnetic field which the switching element 57 brings against the force of the spring F into a first position in which the contact s57 is closed. If necessary, a resistor 78 can be provided in the between the phase and the associated closing contact s771 to limit the current.

The premagnetization required to maintain the operating state of the device indicated by a resistor 69 is effected by a current which, when the button 77 is not pressed, via the phase L1, a resistor 74, a resistor 75, the safety line 4, the associated winding and finally flows through a resistor 76 over the neutral conductor N. If there is no overvoltage or undervoltage, the switching element 57 is brought into the first position by the premagnetization, in which the associated contact s57 is closed, the switching device R47 is activated and the device is connected to the mains via the contacts s471 to 473. - 42 -

It can be seen from FIG. 20 that within the device 6 several lines start both from the phase and from the safety line 4, which run at a small distance from one another. This can also be achieved by lines printed on the inside of the housing of the device. Water penetrating into the device leads to conductive connections between the lines emanating from the phase and the lines emanating from the safety line, so that a fault current flows via the safety line 4 to the associated winding of the summation converter. The magnetic field thereby caused leads to a deflection of the switching element 57 into the second position, in which the contact s57 opens, the switching device R47 is deactivated and the device 6 is disconnected from the mains.

A test button 79 can also be provided in the device for the functional test, which, in the pressed state, triggers a fault current which leads to the protective circuit being switched off.

In addition, any overvoltage detection device configured here as relay 80 can be provided in the device, which, in the event of a selectable overvoltage between phase and safety line, can flow, for example, via a contact s80, a fault current which switches off the protective circuit.

As in the other exemplary embodiments, the switching element 57 is provided with a locking device 61, which was described in detail above.

As additional protection, only outlined fuses 66, 67 can be provided in the feed lines to the summation converter. FIG. 21 shows an exemplary embodiment of a protective circuit designed for three-phase current consumers.

The function of the protective circuit corresponds to that of the exemplary embodiments described with reference to FIGS. 17 to 20.

Each of the leads to the summation converter is assigned its own winding. The phases are introduced via outlined fuses 81, 82, 83.

The premagnetization is carried out here by a connecting line having a resistor 84, which has a phase, e.g. S, and on the consumer side of the summation converter with one or more other phases, e.g. R, is connected. The premagnetization can also take place through the selection of other phases, but also through a corresponding connection of one of the phases with the neutral conductor. As described above, the premagnetization acts on the switching element 57 which can be rotated about the axis 56, so that its associated element Contact s57 is closed in a first position and a switching device R47 is activated. As a result, the connected device 6 or a socket is connected to the network via the contacts s471, s472, s473, s474, s475.

By any, here designed as a relay R48 failure erspannungserfassungsei nrichtung occurring between the protective conductor SL and neutral N Fehler¬ or overvoltage is detected, and in this case over a lying in the supply line to the switching means R47 NC Ö48 the ^"Relay R48 separation of Ge ¬ devices 6 carried out by the network by inactivating the switching device R47. This is also deactivated if the failure of a phase R, S, T or a short circuit between the phases with the neutral conductor or the protective conductor is detected.

For this purpose, any three consumers 85, 86, 87 of the same type are connected to the phases on the one hand and to the other to form an artificial zero point. At the zero point there is a first connection of any insulation and existence monitoring device, here designed as relay R49, the second connection of which is here at the protective conductor SL. However, this could also be led to the neutral conductor N.

If one of the phases fails or in the event of a short circuit, the potential at the junction of consumers 85, 86, 87 shifts and relay R49 picks up. This opens the associated NC contact Ö49, which is also in the supply line to the switching device R47. As a result, the switching device R47 is disconnected from its supply voltage and inactivated, which leads to the associated closing contacts s471 to s475 opening and the device 6 being disconnected from the mains.

In parallel with the resistor 84, a test button P with a series resistor 84a, which is protected against overvoltages, is provided, by means of which a fault current can be generated for the functional test of the protective circuit.

The locking mechanism 61 of the switching element 57 coincides with that of the exemplary embodiments described above. FIG. 22 shows a further exemplary embodiment of the protective circuit which has a summation converter without premagnetization. It is a circuit suitable for insulated devices. The circuit principle shown here can also be transferred, for example, to protective circuits for three-phase motors and to devices with protective conductors.

The phase L1 and the neutral conductor are each assigned a winding, the two-core selected safety line 4 here two windings, the windings being selected so that the magnetic field cancel each other out due to the currents flowing on the phase and neutral conductor, while the magnetic fields cancel each other out due to currents reinforce each other in the security line.

The first wire of the safety line 4 starts from the phase and is led to the electrical device 6 via a first resistor 88 and the first winding 89. In order to increase security, the first wire is fanned out into a plurality of lines which are arranged near a plurality of lines of the second wire of the safety line 4 inside the device. The closely spaced lines of the wires have several non-isolated areas. The second wire leads from the electrical device 6, via a second winding 90 and via a second resistor 91 to the neutral conductor N. Phase and the neutral conductor lead from the network to two contacts k1, k2, which are coupled to one another and, for example, mechanically, here are biased by a tension spring 92. The pretensioning causes the contacts to change into the opened state if they are not prevented from doing so by a locking device 93, which is shown here only on the basis of a schematic diagram. ! - 46 -

The locking device 93 is provided with a tilting element 95 rotatable about an axis 94 with or made of ferromagnetic material or the like. connected. A biasing device designed here as a spring 96 holds the tilting element 95 and the locking device 93 in a position in which the prestressed contacts k1 and k2 are kept closed.

If a fault current and / or faulty voltages occur in the safety line or if current flows from the supply lines into the environment, a magnetic field is generated in the total converter, by which the tilting element 95 is attracted and rotated about the axis 94.

As a result, the locking device 93, as indicated by the arrows in FIG. 22, is moved downward. This has the result that the locking action is canceled and the spring 92 brings the contacts k1, k2 into the open position. As a result, the summation converter or the electrical device is disconnected from the mains.

Due to the fanning out of the first and second wires of the safety line 4 in the device 6, individual drops of water lead to a conductive connection of the wires and to a fault current. This increases security.

An overvoltage derivation device 97 can be connected to the phase and neutral conductor, via which a selectable overvoltage flows to a current. This also triggers the protective circuit, ie the tilting element 95 is attracted and the electrical device is disconnected from the mains. i - 47 -

22, other elements of other exemplary embodiments described above can be included, such as e.g. an insulation monitoring device with which short circuits between the lines but also the failure of a phase can be detected.

The following applies preferably to all protective circuits with summation converters according to FIGS. 17 to 22: The windings of phase (s) and safety conductor or protective conductor are arranged in such a way that the resulting magnetic fields add up. The number of turns can be chosen freely

Basically, it is stated that the individual elements mentioned on the basis of individual exemplary embodiments are interchangeable within the exemplary embodiments and can be combined with one another.

The protective circuit can be accommodated in the installation boxes of electricity generators in the switch boxes of houses or households, as well as in electrical outlets, plugs or housings of electrical devices.

The protective circuit can also be designed so that only devices that have a protective or a safety line are supplied with voltage.

The locking device assigned to the protective circuit can be designed in such a way that it can be operated, for example, by means of the connecting pins of a device plug.

Claims

- 48 -

Protection circuit for electrical devices

Expectations

1

Protection circuit for electrical devices, characterized by

- An insulated safety line (4) running from the associated electrical device (6) to the protective circuit (2), the safety line (4) inside the device (6) having at least one non-insulated area which does not touch live parts ,

- A first switching device (R1) connected to the safety line (4) and a reference potential, and

- A second switching device (R2) which can be actuated by the first switching device (R1) and which lies between phase (10) and neutral conductor (12) of the electrical voltage supply of the device (6) and which, in the activated switching state, the associated device (6 ) from phase (10) and neutral conductor (12), the second switching device (R2) being connected to the phase (10) and the neutral conductor (12) in such a way that after activation by the first switching device (R1) in activated Switching status remains. Protection circuit according to Claim 1, characterized in that the second switching device (R2) can be returned to an inactive fourth switching state by separating phase (10) and / or neutral conductor (12).

Protective circuit according to Claim 1, characterized in that the second switching device (R2) is designed in such a way that it finally disconnects the associated device (6) from the voltage supply.

Protective circuit according to one of Claims 1 to 3, characterized in that it can be accommodated in the housing (24) of the plug (T8) for the voltage supply of the associated device (6).

Protection circuit according to one of Claims 1 to 4, characterized in that the first and the second switching device (Rl,

R2) are designed as relays, the first switching device (R1) having a make contact (sl) and the second switching device (R2) having a make contact (s2) and two break contacts (Ö21, Ö22) - hen i st.

6th

Protection circuit according to one of claims 1 to 5, characterized in that the reference potential with that of the protective contact

(20) of the electrical power supply of the associated device (6) matches. 7.

Protection circuit according to one of Claims 1 to 5, characterized in that the reference potential is independent of the protection contact

05 (20) is selected.

8th.

Protection circuit according to claim 7, characterized in

10 that as a reference potential, the phase (10) of the connector

(18) is used.

Protection circuit according to claim 7,

15 characterized in that the neutral potential (12), the phase

(10) and / or the protective contact (20) of the plug (18) is used.

20 10.

Protection circuit for electrical devices, characterized by

- a plane of the associated electrical device (6) for the protection circuit (2), isolated Sicher¬ t _e integrated circuit (4), wherein the safety line (4)

Inside the device (6) has at least one non-insulated area which does not touch live parts, and

- At least one third switching device (R3) with _3π a first connected to a reference potential

Connection and a second connection, which is connected to the safety line (4) in a first, deactivated switching state of the third switching device (R3), while the voltage supply of the device (6) via phase (10) and neutral conductor (12) is guaranteed, and which is connected in a second, activated switching state of the first switching device (R3) in such a way that the third switching device (R3) automatically maintains itself in the activated state while the voltage supply of the device (6) via phase (10) and neutral conductor (12) is interrupted.

11th

Protective circuit according to Claim 10, characterized in that the third switching device (R3) can be returned to the inactivated fourth switching state by separating phase (10) and / or neutral conductor (12).

12th

Protective circuit according to Claim 10, characterized in that the third switching device (R3) is designed such that it finally disconnects the associated device (6) from the voltage supply.

13th

Protective circuit according to one of Claims 10 to 12, characterized in that it can be accommodated in the housing (24) of the plug (18) of the associated device (6) which serves to supply voltage.

14. Protection circuit according to one of claims 10 to 13, characterized in that the third switching device (R3) is formed as a relay, which has a changeover contact (u3) and two break contacts (Ö31 and ö32). 15.

Protection circuit according to one of Claims 10 to 14, characterized in that the first connection of the third switching device (R3) to the neutral conductor (12) of the voltage supply and in the second, activated switching state of the third switching device (R3) the second connection via the Switchover t contact (u3) and connected to the phase (10) via a series resistor (22).

16th

Protection circuit according to one of Claims 10 to 14, characterized in that the first connection of the fourth switching device (R4) to the neutral conductor (12) of the voltage supply and in the second, activated switching state of the third switching device (R3) the second connection via the Changeover t contact (u3) and over. a transformer (26) is supplied with voltage.

17th

Protection circuit for electrical devices, characterized by

- An insulated safety line (4) running from the protective circuit to the associated electrical device (6), the safety line (4) inside the electrical device (6) comprising at least one non-insulated area (34) which does not touch live parts , 35, 36),

- a fifth switching device (R5), via which the electrical device (6) can be connected to the voltage supply, and '

-'one sixth switching device (R6) assigned to the fifth switching device (R5) and connected to the safety line (4). 18th

Protective circuit according to • Claim 17, characterized by an energy store (c) which can be connected to the fifth switching device (R5) via a switching element.

19th

Protective circuit according to Claim 17 or 18, characterized by a supply circuit u d / connected to the voltage supply of the electrical device or by series resistors (30, 31) arranged in the supply line to the fifth switching device.

20th

Protection circuit for electrical devices, characterized by at least one device for detecting the voltages and / or currents present in the voltage supply of the electrical device.

21st

Protective circuit according to Claim 20, characterized in that the device for detecting the voltage between the at least one phase (R, S, T) and neutral conductor (N) and / or protective conductor (SL) is designed.

22

Protective circuit according to Claim 20 or 21, characterized in that the device is designed to detect the voltage present between the neutral conductor (N) and the protective conductor (SL). ; - 5 -

23rd

Protective circuit according to one of Claims 20 to 22, characterized by a switching element which can be controlled by the device and which switches the voltage supplied by the voltage supply directly or via at least one switching device.

24. Protection circuit according to one of claims 20 to 23, characterized by a further device which detects the forwarded voltages and / or currents.

25

Protective circuit according to Claim 24, characterized in that the further device has switching devices for detecting the voltages lying between the at least one phase and the neutral conductor and / or the protective conductor and / or between the neutral conductor and protective conductor, the switching devices having a predeterminable minimum voltage speak to.

26

Protective circuit according to one of Claims 20 to 25, characterized by a summation converter which detects the currents flowing on all lines.

27th

Protective circuit according to Claim 26, characterized in that the summation converter is at least one of the following

Elements include: a switching device, a surge arrester, a rectifier, a condenser gate, a potentiometer for adjusting the sensitivity of the device, and / or a switching element for triggering the switching device, the switching device interrupting the voltage supply to the electrical device if the sum of the detected currents is not equal to zero and / or greater than a predetermined value i st.

28th

Protection circuit according to one of Claims 20 to 27, characterized by a device for detecting the currents flowing on one or more lines, which has at least one of the following elements: a coil running around the respective conductor, a switching device, a switching element for triggering the Switching device, an overvoltage supporter, a rectifier, a capacitor, a potentiometer for adjusting the response sensitivity of the switching device and / or a resistance, the switching device supplying the voltage to the electri¬ when a predetermined overcurrent is reached on one of the lines device interrupts.

29.

Protection circuit according to claim 20, characterized in that the device has an insulation monitoring circuit of the at least one phase.

30th

Protection circuit according to Claim 29, characterized by a switching device which interrupts the voltage supply to the electrical device when an insulation fault on the lines leads to a short circuit which leads to the neutral conductor and / or the protective conductor, and / or if at least one of the phases of the voltage supply fails.

31st

Protective circuit according to Claim 29 or 30, characterized in that a zero potential 1 is created by means of the same type of consumers assigned, which is placed on one side of the switching device, the other side of which is connected to the neutral conductor and / or the protective conductor 1 .

32nd

Protective circuit according to one of Claims 20 to 31, characterized by a first switching element which can be controlled by the switching devices in such a way that the voltage supply of the electrical device is not switched on when a fault occurs or directly or via at least one switching device is interrupted.

33.

Protection circuit according to Claim 32, characterized in that the first switching element can be actuated by a second switching element.

34.

Protection circuit according to Claim 33, characterized in that the second switching element switches off the first switching element in the activated state.

35.

Protection circuit according to claim 34 _; characterized, - -

that the second switching element can be locked in the activated state.

36.

Protection circuit according to one of Claims 20 to 35, characterized by an acoustic and / or optical display device which can be connected to the switching devices for displaying errors.

37.

Protective circuit according to claim 23, characterized in that the mains voltage or the switched voltage is delivered to the electrical device via safety devices.

38.

Protection circuit according to claim 37, characterized in that the safety device at least one of the following elements. having :

- At least one device for detecting the currents flowing on the at least one phase, the neutral conductor and / or the protective conductor;

the sum converter comprising the at least one phase, the neutral conductor, the protective conductor and / or the safety line;

- a device for recording the between the phase and the nu! 1 phase, the phase and the protective conductor, and / or voltage lying between the neutral conductor and the protective conductor;

a device for detecting insulation faults in the lines and / or the failure of the voltage on one or more phases; - One of the connection of the voltage supply to the electrical device serving switching device which can be controlled by the / said elements.

39.

Protection circuit according to claim 37, characterized in that

- The neutral conductor and the protective conductor of the electrical device are guided to the neutral conductor of the supply network and

- The safety device has a switching element provided in the line running from the protective conductor of the device to the neutral conductor of the supply network, which interrupts the voltage supply of the electrical device directly or by means of at least one switching device when fault currents occur on the protective conductor.

40th

Protection circuit according to Claim 37, characterized in that the safety device has at least one of the following elements:

a sum converter comprising the at least one phase and / or the neutral conductor and / or the protective conductor and / or the safety line;

- At least one device for detecting the phase and protective conductor and / or between phase and neutral conductor and / or between the phases;

- A first switching device assigned to the protective line for detecting an overcurrent;

- A second switching element which can be controlled by the summation converter and / or the device and / or the first switching element for connecting the electrical device to the voltage supply; - A third switching element, by means of which the second switching element can be controlled in the event of a fault in such a way that the electrical device is disconnected from the voltage supply.

41.

Protection circuit according to claim 37, characterized in that the safety device

- A temperature-dependent resistance in the protective line and

- Has at least one switching element assigned to the resistor, through which the voltage supply of the electrical device can be interrupted directly or via at least one switching device.

42nd

Protective circuit according to Claim 37, characterized in that the safety device is connected to at least one phase and to the neutral conductor, that between the voltage supply and the safety device a separating device is provided for the galvanic separation of the safety device from the supply network, that associated consumers via the supply lines An artificial zero point is created, to which a first connection of a switching device is connected, the second connection of which can be connected to the electrical device, the switching device being used for interruption of the voltage supply in the event of error voltages occurring in the electrical device Device.

43.

Protection circuit for electrical devices, which has a summation converter, characterized by at least one device which impresses a defined current into the summation converter; and a switching element which can be controlled by the magnetic field generated in the summation converter and through which an electrical device can be connected directly to the voltage supply or via at least one switching device.

44.

Protective circuit according to Claim 43, characterized in that the switching element can be brought into a position by undervoltage and / or overvoltage in which the voltage

Supply of the electrical device is interrupted directly or via at least one switching device.

45.

Protective circuit according to Claim 43 or 44, characterized by at least one device for detecting the voltages present between the at least one phase, the neutral conductor and / or protective conductor and / or between the neutral conductor and the protective conductor and / or between those from the summation converter to the electrical one Device carrying lines present voltages, the device being assigned to the switching element and / or at least one switching element.

46.

Protection circuit according to claim 43 or 44, characterized in that there is only a connection between the at least one phase and the neutral conductor of the voltage supply and the summation converter, that in addition to phase and

Neutral conductor at least one safety line running from the sum converter to the electrical device is provided. 47th

Protective circuit according to claim 46, characterized in that the safety line and / or the protective conductor in the interior of the electrical device has at least one unisolated area near a current-carrying part of the device.

48.

Protective circuit according to Claim 47, characterized in that the safety line is assigned to the switching element and / or at least one scarf element in such a way that it is not possible to start up the electrical device when the safety line is interrupted and / or that the voltage supply is interrupted if, in the event of a fault, a conductive connection is established between the safety line and live parts in the device.

49.

Protection circuit according to one of Claims 43 to 48, characterized by at least one insulation monitoring device which is assigned to the lines leading to the summation converter and / or outgoing from it.

50.

Protective circuit for an electrical device, which has a summation converter, characterized in that the summation converter has at least two windings, each of which is assigned to one wire of a safety line running between the summation converter and the electrical device. 5 1.

Protective circuit according to Claim 50, characterized in that the windings are each assigned to one wire of the safety line in such a way that the currents flowing in the wires result in adding magnetic fields.

52.

Protective circuit for electrical devices, characterized by a switching element which interrupts the connection between the voltage supply and the electrical device directly or via at least one switching device when exposed to moisture.

53.

Protection circuit according to claim 52 ^,! characterized in that the switching element has a pretension which is canceled by a moisture-sensitive tensioning element, the clamping force of the tensioning element decreasing when exposed to moisture, so that the switching element is triggered and the voltage supply to the electrical device is interrupted.

54.

Protection circuit for electrical devices, characterized by a combination of the devices that detect errors in the connected electrical device and the

Devices that detect faults in the voltage supply of the electrical device.

55. Plug for an electrical device, characterized by a protective circuit accommodated in the housing of the plug according to one of claims 1 to 54.

56. 05 socket for an electrical device, characterized by a protective circuit accommodated in the housing of the socket according to one of claims 1 to 54.

10 57.

Housing for an electrical device, characterized by a protective circuit accommodated in the housing according to one of claims 1 to 54.

15

58.

Schal ei nri device, characterized in that it has a protective circuit according to one of claims 1 to 54 and that it _. is provided for a power generator or at any point in a supply network between the power generator and the consumer or for a consumer.