DE102011081950B4 - Home appliance with an electric protection device - Google Patents

Abstract

Household appliance (1) with an electrical protection device, comprising: - an electrical contact (38) provided for electrical contact with the domestic electrical appliance (1), the contacts (39, 40) for an outer conductor and a neutral conductor and a protective contact (41) for a protective conductor of the household appliance (1), - for at least indirectly contacting a socket (24) of an electrical supply network (23) provided electrical contact (34, 52), the contacts (35, 36, 53, 54) for an outer conductor (L1) and a neutral conductor (N) and a protective contact (37, 55) for a connected to the socket (24) protective conductor (PE) of the supply network (23), wherein the contacts (39, 40, 35, 36, 53 , 54) of the two contacts (38, 34, 52) are electrically connected, at least in a first operating state of the protective device (21, 51), - electrically connect a terminal (43) provided with a ground potential a switch (44) which optionally in a first switching position (A), the two protective contacts (37, 55, 41) of the protective device (21, 51) and in a second switching position (B) the terminal (43) with the protective contact (41) for electrical contact with the household electrical appliance (1) provided electrical contact (38) electrically connects, - a current source (45) which is adapted to an electric current in the protective contact (37, 55) of the at least indirectly contacting the socket (24) provided Kontaktierung (34, 52) and / or in the terminal (43) impress, and - a voltage measuring device (46), which is arranged, an electrical voltage between the contact (36) for the neutral conductor (N) for at least indirectly contacting the socket (24) provided for contacting (34, 52) and, depending on the switching position (A, B) of the switch (44), the protective contact (37) for at least indirectly contacting the sockets e (24) provided to determine contact (34, 52) or the terminal (43), wherein the protective device (21, 51) is arranged to check whether the protective conductor (PE) and / or the connection of the terminal (43) is sufficiently low impedance with the ground potential and only the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34, 52) electrically connects when the means of the voltage measuring device (46) detected voltage is less than one Maximum voltage is.

Description

The invention relates to a household appliance, in particular a dishwasher, washing machine, a tumble dryer, stove, or the like, with an electrical protection device.

The DE 37 43 034 A1 discloses a circuit breaker / residual current circuit breaker designed as an intermediate connector. This automatically disconnects a connected electrical device when a fault current occurs.

The US Pat. No. 3,868,566 discloses a device for determining an electrical potential which is applied between a housing of an electrical device and a reference ground.

The DE 60 2004 002 588 T2 and the US 5,943,199 A each discloses a safety device with a Erdfehlerstromschutzschaltung. This can be integrated into a plug of a household appliance, which includes connections for contacting the household appliance to an outer conductor and a neutral conductor of a supply network.

The DE 26 52 190 A1 discloses a safety plug with built-in residual current circuit, which is connected via a power socket with the mains. The safety plug is connected via a connecting cable with a multiple socket, each comprising an electrical contact having contacts for an outer conductor and a neutral conductor and a protective contact for a protective conductor of an electrical device. The multiple socket includes a terminal intended to be electrically connected to a ground potential. The safety plug comprises a provided for contacting a socket of an electrical supply network electrical contact having contacts for an outer conductor and a neutral conductor and a protective contact for a connected to the socket protective conductor of the supply network, wherein the contacts of the two contacts at least in a first operating state of the protective device are electrically connected. The multiple socket comprises a circuit which is arranged to check whether the protective conductor and / or the connection of the terminal to the ground potential is sufficiently low-resistance.

The object of the invention is to specify for an electrical household appliance, an electrical safety device with improved safety concept or to provide an electrical appliance with such an improved protective device.

The object of the invention is achieved by a household appliance having the features of claim 1.

The invention further relates to an electrical protection device according to claim 9.

The protection device according to the invention is e.g. intended to be interposed between the respective electrical device, in particular household appliance and its power cord. The household electrical appliance is e.g. a household dishwasher, washing machine, a tumble dryer, refrigerator, stove, or the like. The protective device comprises for this purpose the two contacts, of which in operation one is connected to the household electrical appliance and the other at least to the socket. In the first operating state, e.g. can be realized by means of a switch, in particular a three-pole switch of the protection device, the contacts of the two contacts are electrically connected, so that the mains voltage of the supply network is applied to the respective electrical device, in particular household appliance. Furthermore, the electrical contact intended for contacting a domestic electrical appliance has a protective contact which, when the switch is in its first switching state, is supplied via the socket to the protective conductor of the supply network, i. the electrical house installation is connected. In addition, the protection device still comprises the connection which is intended to be connected to a ground potential, that is to say to "ground". The connection to the ground potential may e.g. be realized by the connection is connected to a faucet or other electrically well conductive object in the vicinity of the household electrical appliance. If the switch is in its second switching position, then the protective conductor of the electrical device, in particular household appliance, is no longer connected to the protective conductor of the socket, but via the connection to the ground potential. Thus, it is possible for the household electrical appliance to get a secure connection with "ground", even if the protective conductor of the house installation is defective or not available.

The protective device according to the invention can be interposed between the household electrical appliance and its power cord. Then, according to an embodiment of the protective device according to the invention, the household appliance having a power cable socket and provided for electrical contact with the household electrical appliance electrical contact may be formed as a plug which forms a plug connection with the power cable socket. The provided for at least indirectly contacting the socket of the electrical supply network electrical Contacting may preferably be formed as a power cable socket. Then it is only necessary to install the protective device according to the invention, to remove the power cord of the household electrical appliance from the power cord socket and grind the guard.

The protective device according to the invention may also be designed as a mains cable, i. it is integrated in a power cable. In this case it is e.g. possible to replace a conventional power cord with the running as a power cord protection device according to the invention. In this case, preferably, the household electrical appliance has a power cable socket and the electrical contact provided for electrical contact with the household electrical appliance is designed as a plug which forms a plug connection with the power cable socket. The at least indirect contacting of the socket of the electrical supply network provided electrical contact is then preferably designed as a power plug, which can then be plugged into the socket for connection of the electrical household appliance to the power supply.

For example, in order to be able to assess automatically whether the protective conductor and / or the connection via the connection with the ground potential is sufficient for electrical protection, the protective device according to the invention is set up in such a way that it automatically checks whether the protective conductor and / or the connection of the connection are sufficiently low impedance with the earth potential.

For this purpose, the protective device according to the invention comprises a power source which is adapted to impress an electrical current, which in particular is a constant electric current, into the protective contact of the at least indirect contacting of the socket provided for contacting and / or in the terminal. If, for example, it is to be checked whether the protective conductor connected to the socket is sufficiently low-impedance, then the current source impresses its current into the protective contact of the contact arrangement provided for at least indirect contact with the socket. This can e.g. be achieved by the switch is in its first switching position. If, for example, it is to be checked whether the connection via the connection with the ground potential is adequately low-impedance, then the current source injects its current into the connection. This can e.g. be achieved by the switch is in its second switching position.

The protective device according to the invention has a voltage measuring device, which is arranged, an electrical voltage between the contact for the neutral conductor provided for at least indirectly contacting the socket contacting and, depending on the switching position of the switch, the protective contact intended for at least indirect contacting the socket contacting or determine the connection. In fact, if the checked electrical connection, i. the protective conductor or the connection to the ground potential is sufficiently low-impedance, then when current is impressed by the current source, this voltage is relatively small, e.g. at an impressed current of 0.5 mA maximum 2.5 V. An evaluation of this voltage can then be used to determine whether the switch is operated in its first or in its second switching position during operation of the electrical household appliance.

The protective device according to the invention is arranged to electrically connect only the contacts of the two contacts, in particular by means of a three-pole switch, if the voltage determined by means of the voltage measuring device is less than a maximum voltage of e.g. 2.5V with an impressed current of 0.5 mA.

• - zunächst die Schutzvorrichtung in einem zweiten Betriebszustand zu betreiben, in dem die beiden Kontakte insbesondere mittels eines dreipoligen Schalters voneinander elektrisch isoliert sind,
• - anschließend zu überprüfen, ob der Schutzleiter ausreichend niederohmig ist, und
• - wenn der Schutzleiter ausreichend niederohmig ist, bei Betreiben des Schalters in seiner ersten Schaltstellung die Kontakte der beiden Kontaktierungen insbesondere mittels des dreipoligen Schalters elektrisch zu verbinden.

According to a preferred variant of the protective device according to the invention, this is set up,

• first to operate the protection device in a second operating state, in which the two contacts are electrically insulated from one another, in particular by means of a three-pole switch,
• - then check whether the protective conductor is sufficiently low-resistance, and
• - When the protective conductor is sufficiently low impedance, when operating the switch in its first switching position to electrically connect the contacts of the two contacts, in particular by means of the three-pole switch.

According to this variant, it is therefore first checked before connecting the household electrical appliance to the electrical supply network, whether the connected to the socket protective conductor safely, i. low impedance is enough. This is achieved in particular by impressing the current by means of the current source into the protective contact in question and by evaluating the corresponding measured voltage by means of the voltage measuring device. Only when the protective conductor is sufficiently low-resistance, the household electrical appliance is connected to the neutral conductor and the outer conductor of the socket. In addition, the protective conductor of the household electrical appliance is then connected via the protective device to the protective conductor of the supply network.

According to a further variant of the protective device according to the invention, this is set up check whether the connection to the earth potential via the connection is sufficiently low-resistance, if checking the protective conductor showed that it is not sufficiently low-resistance. If the connection to the ground potential via the terminal is sufficiently low-impedance, the contacts of the two contacts are electrically connected in particular by means of the three-pole switch when operating the switch in its second switching position. Thus, it is first checked before connecting the electrical device, in particular household appliance, whether the protective conductor provides adequate protection. If this is not the case, then the connection to the ground potential is checked via the connection, and the domestic appliance is only switched on if one of the two electrical connections is sufficiently low-resistance. If the protective conductor is not sufficiently low-resistance, but the connection via the connection to the ground potential is sufficiently low-resistance, then the switch is operated in its second switching position, ie the protective conductor of the household electrical appliance is not connected to the protective conductor which is connected to the socket, but via the connection to the earth potential.

In order to improve the safety of the protective device according to the invention, this is set up according to an expedient embodiment to check whether an electrical voltage is applied to the protective conductor. If this is too high, then this may result in the event of the electrical appliance, in particular domestic appliance, possibly causing life-threatening electrical current. If such is present or if it is too high, then it can be provided that the protective device automatically separates the contacts of the two contacts, in particular by means of the three-pole switch.

In order to measure the voltage at the protective conductor or a fault current resulting therefrom, the protective device according to the invention may preferably comprise a series connection of a current measuring device and a resistor which is connected between the protective contact of the at least indirect contacting of the socket provided contact and the terminal Protective device is set up, in particular by means of a three-pole switch to electrically disconnect the two contacts when the determined by means of the current measuring device electrical current exceeds a maximum value. The maximum value is e.g. 0.1 mA. The value of the resistance is e.g. 0.5 MΩ assuming a maximum allowable voltage of 50 V.

The protective device according to the invention thus offers an additional electrical safety concept in the mains supply line. If necessary, it also provides for a poor or even missing ground connection (protective conductor) to the house connection box or socket for the household electrical appliance, which is in particular a dishwasher, washing machine, tumble dryer, refrigerator, freezer, stove or the like, for the customer adequate protection against electric shock.

The protective device according to the invention can be used advantageously also in other electrical devices.

The protection device according to the invention is e.g. realized as a Zwischenstecklösung between the respective household electrical appliance and the actual power supply line. The protection device according to the invention offers the possibility of making an additional reference to the earth, e.g. by electrically connecting the connection to a faucet.

• - Überprüfung, ob der mit der Steckdose verbundene Schutzleiter spannungsführend ist oder nicht (über den Schutzleiter oder die Verbindung zum Erdpotenzial). Diese Überprüfung kann beim Einschaltvorgang und/oder kontinuierlich im eingeschalteten Zustand durchgeführt werden.
• - Überprüfen, ob der Schutzleiter unterbrochen ist (über Schutzleiter und/oder Verbindung zum Erdpotenzial). Ein gewisser Übergangswiderstand zur Erde kann erlaubt sein. Dieser Übergangswiderstand kann auf Grundlage der erlaubten Berührungsspannung festgelegt sein. Diese Überprüfung wird z.B. beim Einschaltvorgang und kontinuierlich im eingeschalteten Zustand durchgeführt.
• - Auslöseschwelle von einem Differenzstrom >= 10 mA. Die erfindungsgemäße Schutzvorrichtung kann bei einem Differenzstrom von beispielsweise 10 mA zwischen Außenleiter und Neutralleiter das angeschlossene elektrische Gerät, insbesondere Haushaltsgerät wie z.B. eine Geschirrspülmaschine, insbesondere 3-polig vom Netz trennen. Dabei können Gleichströme berücksichtigt sein. Diese Überprüfung wird vorzugsweise kontinuierlich im eingeschalteten Zustand durchgeführt.
• - Auswahl Schutzkontakt oder Verbindung über den Anschluss zum zusätzlichen Erdpotenzial. Die erfindungsgemäße Schutzvorrichtung kann beim automatischen Einschalten überprüfen, ob der regulär zur Verfügung stehende Schutzleiter vorhanden ist und einen entsprechend geringen Widerstand aufweist. Ist dies der Fall, wird vorzugsweise der Schutzleiter für die Schutzfunktion verwendet. Wenn nicht, wird der zusätzliche Anschluss für die zusätzliche Erde überprüft und bei Bestehen dieser Prüfung herangezogen. Erfüllt dieser ebenfalls nicht die Anforderungen, wird die Versorgungsspannung für den Verbraucher nicht weitergeschaltet.
• - Automatische Funktionsüberprüfung der Auslöseschwelle bei Lastfreiheit. Da die Zugänglichkeit zur Schutzvorrichtung nicht immer gewährleistet ist, kann eine automatische Funktionsüberprüfung der Auslöseschwelle durchgeführt werden. Diese Funktionsüberprüfung kann in regelmäßigen Zeitintervallen ausgeführt werden, wenn keine Last vorhanden ist.
• - Automatisches Einschalten der Versorgungsspannung. Bei Anlegen einer Versorgungsspannung kann die Schutzvorrichtung automatisch mit seinen internen Überprüfungen beginnen und bei erfolgreichem Abschluss wird die Versorgungsspannung für den angeschlossenen Verbraucher (elektrisches Gerät, insbesondere Haushaltsgerät) eingeschaltet.
• - Dreipoliges Abschalten des Verbrauchers (elektrisches Gerät, insbesondere Haushaltsgerät). Wird bei der Überprüfung vor dem Einschalten oder bei der kontinuierlichen Überprüfung im Betrieb ein Abschaltkriterium erreicht, wird der angeschlossene Verbraucher, d.h. das elektrische Gerät, insbesondere Haushaltsgerät, vorzugsweise dreipolig abgeschaltet. Nach dem vorzugsweisen dreipoligen Abschalten wird ein erneutes automatisches Zuschalten erst nach einer Spannungsunterbrechung an der Versorgung der Schutzvorrichtung stattfinden.

The protective circuit according to the invention can be designed such that it has one or more of the following functions or that one or more of the following functions are integrated in the protective device:

• - Checking whether the protective conductor connected to the socket is live or not (via the protective conductor or the connection to earth potential). This check can be carried out during the switch-on process and / or continuously in the switched-on state.
• - Check whether the protective conductor is interrupted (via protective conductor and / or connection to ground potential). A certain contact resistance to the earth may be allowed. This contact resistance may be determined based on the allowed touch voltage. This check is carried out, for example, during the switch-on process and continuously in the switched-on state.
• - Trip level of a differential current> = 10 mA. The protective device according to the invention can disconnect the connected electrical device, in particular household appliance such as a dishwasher, in particular 3-pin from the grid at a differential current of for example 10 mA between outer conductor and neutral. In this case, direct currents can be taken into account. This check is preferably carried out continuously in the switched-on state.
• - Selection of protective contact or connection via the connection to additional earth potential. The protective device according to the invention can check during automatic switching on whether the regularly available protective conductor is present and has a correspondingly low resistance. If this is the case, the protective conductor is preferably used for the protective function. If not, then the additional connection for the additional earth is checked and used upon passing this test. If this also does not fulfill the requirements, the supply voltage for the consumer is not switched further.
• - Automatic functional check of the tripping threshold at no load. Since the accessibility to the protection device is not always guaranteed, an automatic functional check of the triggering threshold can be carried out. This function check can be performed at regular time intervals when there is no load.
• - Automatic switching on of the supply voltage. When a supply voltage is applied, the protection device can automatically start its internal checks and on successful completion, the supply voltage for the connected consumer (electrical device, in particular home appliance) is turned on.
• - Three-pole switch-off of the consumer (electrical appliance, especially household appliance). If a switch-off criterion is reached during the check before switching on or during the continuous check during operation, the connected consumer, ie the electrical appliance, in particular domestic appliance, is preferably switched off in three poles. After the preferred three-pole shutdown a renewed automatic connection will take place only after a power interruption to the supply of the protective device.

• 1. eine Haushaltsgeschirrspülmaschine bekannter Bauart,
• 2 ein Netzkabel, eine Schutzvorrichtung und die Haushaltsgeschirrspülmaschine,
• 3, 4 die Schutzvorrichtung, und
• 5 ein Netzkabel mit integrierter Schutzvorrichtung.

Other developments of the invention are given in the dependent claims. The invention and its development and advantages thereof are explained below with reference to drawings. Each show schematically:

• 1 , a household dishwasher of known design,
• 2 a power cord, a fender and the household dishwasher,
• 3 . 4 the fender, and
• 5 a power cable with integrated protection device.

Elements with the same function and mode of action are in the 1 to 5 each provided with the same reference numerals.

The 1 shows a household dishwasher 1 in a perspective view as an example of a household appliance or generally as an example of an electrical device, in particular household appliance.

The household dishwasher 1 has a rinse tank 2 for receiving items to wash, for example, arranged in a stack, as baskets 3 trained dish containers can be arranged. The washing container 2 can by means of a pivotable relative to a horizontal axis door 4 be closed, as is usual. With the door open 4 can the two baskets 3 from the washing container 2 be pulled to load and unload the baskets 3 at least easier.

In the washing container 2 For example, at least two spraying devices are arranged to pressurize the items to be washed with a liquid, which is usually referred to as rinsing liquor. In the case of the present embodiment, the spraying devices are upper and lower spray arms 5 . 6 educated. The liquid can, for example, from a circulating pump, not shown, via a first fluid supply line to the upper spray arm 5 and a second fluid supply to the lower spray arm 6 be encouraged. The circulation pump is driven for example by means of an electric drive, not shown.

The 2 schematically shows the household dishwasher 1 , a protection device 21 which with the household dishwasher 1 can be connected, and a power cord 22 for the electrical connection of the household dishwasher 1 to an electrical supply network 23 or to an electrical outlet 24 of the supply network 23 ,

In the case of the present embodiment, the household dishwasher 1, a device-side power cable socket 7 on, by means of which the household dishwasher 1 directly over the power cord 22 can be connected to the supply network 23 by the for the power cable socket 7 provided first, device-facing plug 25 of the power cord 22 the power cable socket 7 the household dishwasher 1 and the second, mains-facing mains plug 26 of the power cord 22 the socket 24 contacted. In the case of the present embodiment, it is the second power plug 26 of the power cord 22 a Schuko plug, that is a mains plug with a protective contact 29 , In particular, the second power plug comprises 26 next to the protective contact 29 two as contact pins 27 . 28 trained contacts. The contact pins 27, 28 are provided via the socket 24 with an electrical voltage leading outer conductor L1 and a neutral conductor N of the supply network 23 to be contacted electrically. The protective contact 29 is provided with a protective conductor PE of the supply network 23 to be contacted.

The power cable socket 7 of the household dishwasher 1 includes contacts 8th . 9 that are provided via the power cord 22 with the outer conductor L1 and the neutral conductor N of the supply network 23 electrical to be connected. The power cable socket 7 of the household dishwasher 1 also includes a protective contact 10 , which in particular with a ground connection of the household dishwasher 1 , For example, a housing of the household dishwasher 1 , connected is. To with the power cord socket 7 To be connected includes that for the power cable socket 7 provided first connector 25 of the power cord 22 corresponding contacts 30, 31 and a protective contact 32nd

In the case of the present embodiment, that is for the power cable socket 7 provided plug 25 of the power cord 22 not directly with the power cord socket 7 of the household dishwasher 1 but via the intermediate, ie between the power cord socket 7 and the first connector 25 of the power cord 22 inserted protection device 21 , The protection device 21 is in the 3 and 4 shown in more detail.

The protection device 21 includes, for example, a housing 33 , one the first connector 25 the power cord facing mains cable socket 34 with electrical contacts 35, 36 and a protective contact 37 , and one of the device-side power cord sockets 7 facing plug 38 with electrical contacts 39 . 40 and a protective contact 41 ,

Furthermore, in the case of the present embodiment, the protection device comprises 21 a three-pole switch 42 ,

The individual contacts 35 . 36 and the protective contact 37 the power cord facing mains cable socket 34 and the individual contacts 39 . 40 and the protective contact 41 of the device-side power cable socket 7 facing plug 38 the protection device 21 are connected in such a way that when the switch is closed 42 the contact 35 with the contact 39 and the contact 36 with the contact 39 are connected.

The protection device 21 is provided between the household dishwasher 1 and the power cord 21 to be switched between, especially if the outlet 24 not with the protective conductor PE connected or this is defective. This is the first plug 25 of the power cord 22 with the power cable socket 34 the protection device 21 and the plug 38 the protection device 21 with the power cable socket 7 of the household dishwasher 1 connected.

The protection device 21 points next to the power cable socket 34 and plugs 38 trained connections still a connection 43 and a switch 44 on. The connection 43 is provided with the earth potential of the environment of the household dishwasher 1 to be electrically connected, eg with a tap. The connection 43 For example, it is designed as an electrical line that comes out of the housing 33 led out. The desk 44 can be in two different switch positions A . B operate. Is he in his switch position? A switched, like this in the 3 and 4 is shown, then it electrically connects the protective contact 37 the power cable socket 34 the protection device 21 with the three-pole switch 42 , Is the three-pole switch 42 closed, then the protective contact is thus 37 the power cable socket 34 with the protective contact 41 of the plug 38 the protection device 21 connected and thus the household dishwasher 1 not only with the outer and neutral conductors L1 . N of the supply network 23 but also with the protective conductor PE , if available, connected.

On the other hand, is the switch 44 in its second switching position B , then the connection 43 with the three-pole switch 42 connected. Is the three-pole switch 42 closed, then is the household dishwasher 1 only with the outer and neutral conductors L1 . N of the supply network 23 connected, but also via the protective contact 10 the power cable socket 7 of the household dishwasher 1 with the ground potential across the terminal 43 the protection device 21 ,

1. 1. Erkennen einer Unterbrechung des Schutzleiters PE und/oder Erkennen, ob die Verbindung mit dem Erdpotenzial über den Anschluss 43 unterbrochen ist. Insbesondere wird überprüft, ob die Verbindungen mit dem Erdpotenzial und/oder mit dem Schutzleiter PE ausreichend niederohmig sind. Abhängig von dieser Ermittlung wird der Schalter 44 entweder in seine erste Schaltstellung A oder in seine zweite Schaltstellung B geschaltet.
2. 2. Überprüfen, ob eine elektrische Spannung am Schutzleiter PE anliegt.

In the case of the present embodiment, the protection device 21 in particular arranged to perform the following advantageous functions:

1. 1. Detecting a break in the protective conductor PE and / or detecting whether the connection to the earth potential via the terminal 43 is interrupted. In particular, it checks whether the connections to the ground potential and / or to the protective conductor PE are sufficiently low impedance. Depending on this determination, the switch 44 either in its first switching position A or in its second switching position B connected.
2. 2. Check for electrical voltage on the protective conductor PE is applied.

To perform the checks, includes the guard 21 eg one not closer shown electronics, for example, has a microcontroller or a microprocessor, in particular their electrical energy through the outer and neutral conductors L1 , N of the supply network 23 refers.

To an interruption of the protective conductor PE and / or the connection to the earth potential via the connection 44 or to check the resistance of these compounds comprises in the case of the present embodiment, the protection device 21 a power source 45 , which is set up, a constant electric current to the protective conductor PE or to memorize the connection to the earth potential. For verification is the three-pole switch 42 open. This constant current has a voltage drop on the line to be tested. This is done with a voltage measuring device 46 the protection device 21 determined.

For example, the protective conductor PE checked, then, for example, controlled by the electronics, the switch 44 in his first switching position A brought, so that from the power source 45 generated current via the protective contact 37 on the protective conductor PE is impressed. This constant current has on the protective line PE an electrical voltage drop result. In an intact low-impedance connection, the electrical voltage between the neutral conductor N and the protective conductor PE Zero, but at least nearly zero or relatively small. This electrical voltage is determined by means of the voltage measuring device 46 determined, on the one hand, with the contact 36 and, if the switch 44 in its first switching position A located, with the protective contact 37 the power socket 34 the protection device 21 connected is. Exceeds the by means of the voltage measuring device 46 determined voltage a predetermined maximum voltage, then may indicate a poor or even broken connection of the protective conductor PE getting closed.

As with electrical power connectors it may be that it is not ensured that is always inserted in the correct phase, ie that neutral and outer conductor N . L1 are properly assigned, has in the case of the present embodiment, the protection device 21 another tension measuring device 47 on the one hand with the contact 35 and, if the switch 44 in its first switching position A located, with the protective contact 37 the power socket 34 the protection device 21 connected is. Depending on the connection of the power cord 22 with the socket 24 and the power cord 22 with the protection device 21 can either by means of the voltage measuring device 46 the voltage between the neutral conductor N and the protective conductor PE and by means of the tension measuring device 47 the voltage between the outer conductor L1 and the protective conductor PE , or by means of the voltage measuring device 46 the voltage between the outer conductor L1 and the protective conductor PE and by means of the tension measuring device 47 the voltage between the neutral conductor N and the protective conductor PE be determined.

Now at one by means of the power source 45 impressed constant current of, for example, 0.5mA and a maximum considered admissible resistance of the protective line PE of 5kΩ by means of one of the voltage measuring devices 46 . 47 a voltage difference of the protective conductor PE relative to the neutral conductor N measured smaller than 2.5 V (the voltage or voltage difference determined by the other voltage measuring device is considerably larger), it can be assumed that the protective conductor PE sufficiently low impedance, that is intact. Then, for example, controlled by the electronics, the three-pole switch 42 closed, leaving the household dishwasher 1 on the supply network 23 connected.

In the event of an interruption of the protective conductor PE however, the voltage between the neutral increases N and the protective conductor PE or between the contact 36 and the protective contact 37 (or the contact 35 and the protective contact 37 when the contact 35 with the neutral conductor N connected) to the maximum possible voltage value of the power source 45 from eg 12V. This is above the permitted voltage difference and causes the protective conductor PE is not considered suitable and the mains voltage is not switched through to the device side, so the three-pole switch 42 remains open.

Then, for example, controlled by the electronics, the switch 44 in its second switching position B brought, whereby the contact in question of the three-pole switch 42 via the terminal 43 connected to the earth potential.

Now at one by means of the power source 45 imprinted constant current of, for example, 0.5 mA and a maximum permissible resistance of the electrical connection to the ground potential of, for example, 5 kΩ by means of one of the voltage measuring devices 46 . 47 a voltage difference of this connection smaller than 2.5 V measured (the voltage or voltage difference determined by the other voltage measuring device is significantly larger), it can be assumed that the connection to the ground potential is sufficiently low impedance. Then, for example, controlled by the electronics, the three-pole switch 42 closed, leaving the household dishwasher 1 on the supply network 23 connected.

However, if the connection to earth potential is interrupted, the voltage between them increases the neutral conductor N and the earth potential or between the contact 36 and the connection 43 (or the contact 35 and the connection 43 when the contact 35 with the neutral conductor N connected) to the maximum possible voltage value of the power source 45 from eg 12V. This is above the permitted voltage difference and causes the connection to the ground potential to be considered inappropriate and the line voltage is not switched through to the device side.

In the case of the present embodiment, the protection device 21 Also set up, especially in the operation of the household dishwasher 1 determine if a voltage on the protective conductor PE is applied. For this purpose, the protective device 21 comprises a current measuring device 48 , which is connected in series with a resistor 49. The series connection of the resistor 49 and the current measuring device 48 is between the protective contact 37 the power cable socket 34 the protection device 21 and the connection 43 switched to the current between the protective conductor PE and earth or ground potential. The resistor 49 is relatively high impedance and has, for example, a value of 0.5 MΩ. Exceeds the means of the current measuring device 48 determined current, a predetermined threshold, for example, 0.1 mA, the mains voltage is not switched to the side of the device, ie is the three-pole switch 42 not closed or automatically opened.

In the case of the present embodiment, the protection device 21 set up so that they automatically switch the three-pole 42 closes after the functional tests described above have been successfully completed.

Furthermore, with intact protective conductor PE the protective conductor PE switched on, ie the switch 44 in his first switching position A brought. Otherwise, the switch 44 in its second switching position B brought to the connection 43 to reach a connection with the earth potential.

The automatic function check becomes free of load, ie with the three-pole switch open 42 , carried out.

In addition, it is automatically detected in the case of the present embodiment, whether a voltage at the protective conductor PE before closing the three-pole switch 42 is applied. This is also during the operation of the household dishwasher 1 checked.

The protection device 21 can also be designed such that it performs an automatic functional check of the release threshold at no load. This function check can be performed at regular time intervals when there is no load.

The in the 2 to 4 shown protection device 21 is designed so that it is between the power cord 22 and the household dishwasher 1 is switched. It is also possible the protection device 21 in a power cord 51 to integrate, as in the 5 is shown. The power cord 51 includes the plug 38 with its contacts 35, 36 and the protective contact 37 for directly contacting the power cable socket 7 of the household dishwasher 1 , Instead of the power cord socket 34 indicates the power plug 51 with integrated protective device a mains plug 52 with as contact pins 53 . 54 trained contacts, which are provided via the socket 24 with the outer conductor L1 and the neutral conductor N of the supply network 23 to be contacted electrically. The power plug 52 also has a protective contact 55 on which is provided with the protective conductor PE of the supply network 23 to be contacted.

Furthermore, the contact pins 53 . 54 of the power plug 52 with the switch 42 and the protective contact 55 of the power plug 52 with the switch 44 connected. The series connection of the resistor 49 and the power source 48 is between the protective contact 55 of the power plug 52 and the connection 43 connected. The voltage measuring devices 46 . 47 are with the contact pins 53 . 54 of the power plug 52 connected.

LIST OF REFERENCE NUMBERS

1

Domestic dishwasher

2

rinse tank

3

baskets

4

door

5.6

spray arm

7

Power Input

8, 9

contacts

10

shockproof

21

guard

22

power cable

23

supply network

24

socket

25

plug

26

power plug

27, 28

pin

29

shockproof

30-32

contact

33

casing

34

Power Input

35, 36

Contact

37

shockproof

38

plug

39, 40

Contact

41

shockproof

42

switch

43

connection

44

switch

45

power source

46.47

Voltage measuring device

48

Current measuring device

51

power cable

52

power plug

53, 54

pin

55

shockproof

A, B

switch position

L1

outer conductor

N

neutral

PE

protective conductor

Claims (9)

Household appliance (1) with an electrical protection device comprising: - an electrical contact (38) provided for electrical contact with the domestic electrical appliance (1), the contacts (39, 40) for an outer conductor and a neutral conductor and a protective contact (41) for a protective conductor of the household appliance (1), - An at least indirectly contacting a socket (24) of an electrical supply network (23) provided electrical contact (34, 52), the contacts (35, 36, 53, 54) for an outer conductor (L1) and a neutral conductor (N) and a protective contact (37, 55) for a with the socket (24) connected to the protective earth (PE) of the supply network (23), wherein the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34 , 52) are electrically connected at least in a first operating state of the protective device (21, 51), a terminal (43) provided to be electrically connected to a ground potential, - A switch (44) which selectively in a first switching position (A), the two protective contacts (37, 55, 41) of the protective device (21, 51) and in a second switching position (B) the connection (43) with the protective contact ( 41) electrically connects the electrical contact (38) provided for electrical contacting with the household electrical appliance (1), a current source (45) which is set up to impress an electrical current into the protective contact (37, 55) of the contact arrangement (34, 52) provided for at least indirect contact with the socket (24) and / or into the terminal (43), and - A voltage measuring device (46) which is arranged, an electrical voltage between the contact (36) for the neutral conductor (N) for at least indirectly contacting the socket (24) provided for contacting (34, 52) and, depending on the switching position (A , B) of the switch (44), the protective contact (37) of at least indirectly contacting the socket (24) provided for contacting (34, 52) or the terminal (43) to determine, wherein the protective device (21, 51) is arranged to check whether the protective conductor (PE) and / or the connection of the terminal (43) to the ground potential is sufficiently low-resistance and only then the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34, 52) electrically connects when the voltage detected by the voltage measuring device (46) is less than a maximum voltage. Household appliance (1) after Claim 1 , characterized in that the household appliance (1) has a power cable socket (7) and which is provided for electrical contact with the household electrical appliance (1) provided electrical contact as a plug (38) which forms a plug connection with the power cable socket (7) , And / or that for at least indirectly contacting the socket (24) of the electrical supply network (23) provided electrical contact is formed as a power cable socket (34). Household appliance (1) after Claim 1 , characterized in that the protective device is designed as a power cable (51), and the household electrical appliance (1) has a power cable socket (7) and the electrical contact for electrical contacting with the household electrical appliance (1) provided as a plug (38) is formed, which forms a plug connection with the power cable socket (7), and / or that for at least indirectly contacting the socket (24) of the electrical supply network (23) provided electrical contact is designed as a power plug (52). Household appliance (1) according to one of Claims 1 to 3 , characterized in that the switch (44) in its first switching position (A) is located when the current source (45) their current in the protective contact (37, 55) of at least indirectly contacting the socket (24) provided for contacting (34, 52) impressed, and / or that the switch (44) in its second switching position (B) is located when the power source (45) impresses its current in the terminal (43), and / or that the electric current is a constant electric current. Household appliance (1) according to one of Claims 1 to 4 characterized in that the protection device (21, 51) is arranged to - initially operate the protection device (21, 51) in a second operating state in which the two contacts (38, 34, 52) are electrically isolated from each other, - subsequently check whether the protective conductor (PE) is sufficiently low-resistance, and - if the protective conductor (PE) is sufficiently low-resistance, in operation of the switch (44) in its first switching position (A) the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34, 52) to electrically connect. Household appliance (1) after Claim 5 , characterized in that the protection device (21, 51) is arranged to check whether the connection (43) is sufficiently low-resistance, if the checking of the protective conductor (PE) showed that it is not sufficiently low-resistance, and if the connection ( 43) is sufficiently low impedance, in operation of the switch (44) in its second switching position (B), the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34, 52) to electrically connect. Household appliance (1) according to one of Claims 1 to 6 , characterized in that the protective device (21, 51) is arranged to check whether an electrical voltage is applied to the protective conductor (PE). Household appliance (1) after Claim 7 characterized by a series connection of a current measuring device (48) and a resistor (49), which between the protective contact (37, 55) and the terminal (43) of at least indirectly contacting the socket (24) provided for contacting (34, 52) is connected, wherein the protective device (21, 51) is arranged to electrically disconnect the two contacts (38, 34, 52) when the determined by means of the current measuring device (48) electrical current exceeds a maximum value. Electric protection device (21) comprising: - An electrical contact intended for electrical contact with an electrical device (38), the contacts (39, 40) for an outer conductor and a neutral conductor and a protective contact (41) for a protective conductor of the device (1), - An at least indirectly contacting a socket (24) of an electrical supply network (23) provided electrical contact (34, 52), the contacts (35, 36, 53, 54) for an outer conductor (L1) and a neutral conductor (N) and a protective contact (37, 55) for a with the socket (24) connected to the protective earth (PE) of the supply network (23), wherein the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34 , 52) are electrically connected at least in a first operating state of the protective device (21, 51), a terminal (43) provided to be electrically connected to a ground potential, - A switch (44) which selectively in a first switching position (A), the two protective contacts (37, 55, 41) of the protective device (21, 51) and in a second switching position (B) the connection (43) with the protective contact ( 41) electrically connects the electrical contact (38) provided for electrical contacting with the electrical device (1), a current source (45) arranged to impress an electrical current in the protective contact (37, 55) of the contact means (34, 52) provided for at least indirectly contacting the socket (24) and / or in the terminal (43), and - A voltage measuring device (46) which is arranged, an electrical voltage between the contact (36) for the neutral conductor (N) for at least indirectly contacting the socket (24) provided for contacting (34, 52) and, depending on the switching position (A , B) of the switch (44), the protective contact (37) of at least indirectly contacting the socket (24) provided for contacting (34, 52) or the terminal (43) to determine, wherein the protective device (21, 51) is arranged to check whether the protective conductor (PE) and / or the connection of the terminal (43) to the ground potential is sufficiently low-resistance and only then the contacts (39, 40, 35, 36, 53, 54) of the two contacts (38, 34, 52) electrically connects when the voltage detected by the voltage measuring device (46) is less than a maximum voltage.

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