Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
  • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
  • H02H5/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays
  • H02H5/083—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays responsive to the entry or leakage of a liquid into an electrical appliance

Definitions

• the invention relates to a protective circuit for both people and devices.
• fault current protection circuits 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.
• 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.
• 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.
• 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 -
• 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.
• the protective circuit is accommodated in the housing of the plug of the associated device which serves for the voltage supply.
• 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.
• 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.
• 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.
• at least one device is provided for detecting the voltages and / or currents present in the voltage supply of the electrical device.
• 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.
• the magnetic field is not sufficient to move the switching element to the first position.
• 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.
• 1 a first exemplary embodiment of a protective circuit in which an existing protective contact is used to obtain a reference potential
• FIG. 2 shows a second exemplary embodiment of the protective circuit in which the neutral conductor is used to obtain a reference potential
• FIG. 3 shows a third exemplary embodiment of the protective circuit in which the phase is used to obtain a reference potential
• 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.
• FIG. 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.
• 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 Sch Anlagen ⁇ s2 and 'two normally closed contacts OE21 or ⁇ 22.
• 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.
• the NC contacts ⁇ 21 and ⁇ 22 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.
• 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 ⁇ 21 or ⁇ 22 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.
• 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.
• 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.
• 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.
• the protective circuit 2 according to FIG. 4 only a single switching device R3 designed as a relay is provided.
• This embodiment has - HO -
• the relay R3 shown has three contacts, namely a changeover contact u3 and two break contacts ⁇ 31 and ⁇ 32. 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.
• the associated break contacts ⁇ 31 and ⁇ 32 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,
• 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. - -
• a fourth switching device R4 designed as a relay is provided, which in addition to a changeover contact u4 and two break contacts ⁇ 41 and ⁇ 42 has an additional break contact ⁇ 43 , 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.
• the relay R4 - like the relay Rl and R3 - and the transformer 26 are designed for 24V.
• 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.
• 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 :
• FIG. 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
• Figure 16 shows an embodiment of the protective circuit with mechanical contact tripping
• FIG. 17 to 21 different embodiments of the protection circuit with a summation converter, which is pre-magnetized.
• Figure 22 shows an embodiment of the protective circuit with a summation converter without bias.
• the exemplary embodiment shown in FIG. 6 differs from that shown in FIGS. 1 to 5.
• 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 Druckein ⁇ 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
• 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.
• 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.
• 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.
• the sixth switching device R6 remains in the activated state even when the capacitor C is discharged and the switching element SCH is opened.
• 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.
• 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.
• the switching element E is also designed here as a relay with five Schi i eß contacts el, e2, e3, e4, e5.
• 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.
• 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.
• 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.
• 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.
• 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
• the switching device R17 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.
• 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 Kochwaehungsei 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 switching device R18 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.
• the switching element has two interacting relays R19, R20.
• 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.
• 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.
• 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.
• 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.
• the second relay 20 of the switching element is provided with two break contacts ⁇ 201, ⁇ 202, 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.
• 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
• 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.
• the associated break contact ⁇ 22 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.
• the second switching device R22 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
• a summation converter 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.
• 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.
• 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.
• the protective conductor running to the consumer or to the socket is connected to the neutral conductor of the supply network.
• 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 -
• connection between the supply network and the consumer is also interrupted by the switching device R if the phase labeled Ll fails.
• a locking device V 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.
• 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.
• 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.
• 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.
• a fifth switching device R36 which is activated whenever one of the two contacts or both are closed.
• an NC contact ⁇ 36 in the supply line to the fourth switching device R35 is opened and its connection to the network is disconnected.
• 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
• All switching devices are designed as relays at game shaft. However, other switching devices can also be used.
• 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.
• 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.
• 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 ⁇ 37 of the first switching device R37 is provided in the connecting line.
• 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 ⁇ 37 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 ⁇ 37 and / or a break contact administrat 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.
• 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).
• NTC negative temperature coefficient
• PTC positive temperature coefficient
• 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 ⁇ 40 in the supply line of the first switching device R39 lies between the protective conductor SL and neutral conductor N.
• 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.
• 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
• 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.
• 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 -
• 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.
• 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,
• a moisture-sensitive element 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.
• 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.
• 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.
• 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.
• the switching element 57 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.
• 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.
• 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 .
• the relays R42, R43, R44 are provided in FIG.
• the relays have break contacts ⁇ 42, i ⁇ 43, ⁇ 44, 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.
• a locking device V which holds the switching element 57, for example, also the contacts ⁇ 42, ⁇ 43 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.
• an NC contact is combined with the locking element, which is indicated by a broken line in FIG. 17.
• 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.
• the safety line 4 has at least one uninsulated area near live parts within the electrical device 6.
• 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.
• the summation converter 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 -
• 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.
• 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.
• 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.
• 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.
• 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.
• 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 locking device 61 is unlocked by actuating the reset button R, which is only indicated here as in the other figures.
• 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 -
• phase and neutral conductor are again arranged in such a way that the resulting magnetic fields cancel each other out.
• 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 -
• 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.
• 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.
• the switching element 57 is provided with a locking device 61, which was described in detail above.
• 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.
• 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.
• the connected device 6 or a socket is connected to the network via the contacts s471, s472, s473, s474, s475.
• 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.
• this could also be led to the neutral conductor N.
• 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.
• 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.
• 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.
• 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.
• the locking device 93 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.
• 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 -
• 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.

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• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Emergency Protection Circuit Devices (AREA)
• Keying Circuit Devices (AREA)
• Details Of Connecting Devices For Male And Female Coupling (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6293786

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• 1986
  • 1986-02-10 DE DE19863604118 patent/DE3604118A1/de active Granted
• 1987
  • 1987-02-10 EP EP19870901027 patent/EP0293376A1/de not_active Ceased
  • 1987-02-10 WO PCT/DE1987/000049 patent/WO1987001902A2/de not_active Application Discontinuation
  • 1987-02-10 JP JP62501160A patent/JPH01501516A/ja active Pending
  • 1987-02-10 AU AU70234/87A patent/AU7023487A/en not_active Abandoned

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