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(11) | EP 2 551 967 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A system protecting electric equipment against disconnection from the power supply network |
| (57) The invention relates to a system protecting electric equipment against disconnection
from the power supply network, applicable in household and/or office electronic equipment
supplied from a common central AC/DC power supply unit. The system comprises an AC
supply source electrically connected with a central AC/DC power supply unit (1) fitted
with at least one output for electric wires (2) for transmitting direct current of
different voltage values and it is fitted with at least one plug-in socket (9a, 9b)
to energize in it household receivers (5) supplied with direct current. The system
according to the invention is characterized by the fact that it comprises a disconnecting
module (3) which is connected into the system between the central AC/DC power supply
unit (1) and the contacts (4) of the plug-in socket (9a,9b). The plug-in socket (9a,9b)
is fitted with a monitoring system (7) which is connected with the disconnecting module
(3).
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[0001] The invention relates to a system protecting electric equipment against disconnection from the power supply network, applicable to household and/or office electronic equipment supplied from a common central AC/DC power supply unit.
[0002] At present, most electric installations are supplied from a 230V AC source. However, all electronic equipment is powered by direct current and therefore it is equipped with systems that convert 230V alternating voltage to any direct voltage, and most often to one of the following: 3.3V, 5V, 12V, 24V or 48V. There are known electric installations in which, parallel with the standard AC supply, a low-voltage DC power supply is distributed, which is generated from a central AC/DC power supply unit. This eliminates the need to install additional AC/DC power supply units in electronic equipment.
Patent description US2007/0029879 describes a distribution network for buildings that comprises a central universal DC supply unit. The presented patent description has revealed two solutions for supplying electric installations with direct current in buildings. The first solution uses a central DC power supply unit connected to a standard AC network. Direct current is distributed to universal sockets through bundles of wires which contain current-carrying wires and communication wires. The other solution contains additionally a DC converter which is installed in the socket. Additionally sockets can have a LED indicator, a cable-winding mechanism, a fan.
[0003] A problem with low-voltage installations is the large value of current which is to be transmitted through the wires, as the electric power used by equipment is the product of voltage and current:
where: U - voltage value
I - current value.
[0004] In a low voltage DC line, e.g. 24V or 48V, used to supply household equipment, current flowing through the wires can reach values from a few to almost twenty amperes. At such values of the current, if an operating piece of equipment, that is one connected to the electric installation, is disconnected from that installation, problems arise because during disconnection an electric arc is generated between the supply socket and the plug. Due to the direct current supply this arc is not self-suppressed as is the case with AC power supply. That is the reason why there is a need to protect electric equipment which is connected to a supply network and which is supplied with direct current against its disconnection during its operation.
[0005] The essence of the protective system according to the invention, comprising an AC supply source electrically connected with a central AC/DC power supply unit, fitted with at least one output for electric wires for transmitting direct current of different voltage values and furnished with at least one plug-in socket for connecting in it household receivers supplied with direct current is that it contains a disconnecting module which is connected into the system between the central AC/DC power supply unit and the contacts of the plug-in socket. In addition, the plug-in socket is provided with a monitoring system which is connected to the disconnecting module.
[0006] Preferably between the contacts of the plug-in socket and the monitoring system, there is a mechanical block connected to the system, which makes it impossible to withdraw the receiver plug from the socket.
[0008] Alternatively, the disconnecting module is situated near the central AC/DC power supply unit and outside the plug-in socket.
[0009] Preferably, the disconnecting module is connected with the monitoring system through communication modules, of which one is located in the plug-in socket and the other near the disconnecting module outside the plug-in module.
[0010] Preferably, the disconnecting module, one of the communication modules and the central AC/DC power supply unit are located in the same casing.
[0012] Alternatively, the monitoring system has the form of an electric circuit with a set of contacts, which is electrically connected with the disconnecting module.
[0013] The advantage of the system according to the invention is that it reduces the possibility that equipment will be disconnected from the DC supply line while it is being supplied. The use of plug-in sockets fitted with the monitoring system which is connected with the disconnecting module provides a protection of electric equipment against its disconnection from the power supply network. Additionally, the use of a mechanical plug block or a system for automatically cutting off the supply current causes that attempts to unplug equipment under load are made difficult. The invention eliminates the occurrence of an arc discharge between the socket and the plug in the case of direct current-powered receivers.
[0014] The invention is presented by an embodiment example in the drawing where fig. 1 shows the system protecting electric equipment against disconnection from the supply network in the first embodiment, in a schematic presentation, fig. 2 shows the system protecting electric equipment against disconnection from the supply network in the second embodiment, in a schematic presentation, fig. 3 shows a schematic of the monitoring system from fig. 1 and fig. 2 in the first embodiment, fig. 4 shows a schematic of the monitoring system from fig. 1 and fig. 2 in the second embodiment, fig. 5 shows a schematic of the mechanical plug block.
[0015] The system protecting electric equipment against disconnection from the supply network comprises an AC/DC power supply unit 1 supplied from an alternating current source whose at least one output, only one output being indicated in the drawing, is connected through electric wires 2, a disconnecting module 3, contacts 4 with an electric or electronic receiver 5 requiring a DC power supply and fitted with a plug 6. The plug 6 can be furnished with a pin 6a which is show in the drawing by a dashed line. A monitoring system 7 which is connected with the disconnecting module 3 is connected to the contacts 4. The monitoring system 7 is furnished with measuring elements, which is not shown in the drawing, which measure the current load by supply current.
[0016] In the first embodiment of the invention, presented in fig. 1, the disconnecting module 3, the contacts 4 and the monitoring system 7 are located in a common plug-in socket 9a and they are connected by signal wires 8.
[0017] In the second embodiment of the invention, presented in fig. 2, the disconnecting module 3 is located outside a contact socket 9b in which, besides the contacts 4 and the monitoring system 7, a first communication module 10a is located. The first communication module 10a communicates with a second communication module 10b which in turn is connected with the disconnecting module 3. In the second embodiment of the invention, the central AC/DC power supply unit 1, the disconnecting module 3 together with the communication module 10b can be located in a common casing 11, which is indicated in the drawing by the dashed line.
[0018] In both embodiments of the invention, in their preferred variety, between the contacts 4 and the monitoring system 7, a mechanical block 16 is connected to the system making it impossible to remove the plug 6 from the plug-in socket (9a, 9b).
[0020] And so, in the first variety, presented in fig. 3, the monitoring system 7a is an electric circuit with sets of contacts 13 which is electrically connected with the disconnecting module 3. For the first embodiment of the invention, the monitoring system 7a is connected with the disconnecting module 3 directly by the wires 8. For the second embodiment of the invention, the monitoring system 7a is connected with the disconnecting module 3 by the wires 8 and the communication modules 10a and 10b.
[0021] In the second variety, presented in fig.4, the monitoring system 7b is an electromagnetic circuit formed from a magnetic coil 14 located on a magnetic core 15. The magnetic core 15 can be made in the form of a pin 6a of the plug 6. The ends of the magnetic coil 14 are electrically connected via the wires 8 directly with the disconnecting module 3 for the first embodiment of the invention. For the second embodiment of the invention, the ends of the magnetic coil 14 are connected with the disconnecting module 3 via the wires 8 and the communication modules 10a and 10b .
[0022] In both embodiments of the invention, if the monitoring system 7a is applied, the pin 6a of the plug 6 is at the same time an element of the mechanical block 16 which prevents the removal of the plug 6 under load. The mechanical block 16 comprises a blocking arbor, preferably in the form of the arbor 6a, a pawl 17, a spring 18, a block releasing mechanism 18 which is connected with signal wires 20 which release the block 16 with the disconnecting module 3. If the mechanism with the mechanical block 16 is used, the plug-in socket 9a or 9b is additionally fitted with a pushbutton for releasing the mechanical block, which is not shown in the drawing.
[0023] The functioning of the system according to the invention is explained for the processes of switching on and switching off.
[0024] The process of switching on:
Insertion of the plug 6 into the plug-in socket 9a, 9b is detected by the monitoring system 7. The monitoring system 7 sends a signal about the presence of the plug to the disconnecting module 3 through the wires 8 directly to the disconnecting module or through communication modules 10a and 10 b and wires 8. The disconnecting module 3 turns on the current that supplies the connected receiver 5.
[0025] The process of switching off:
Removal of the plug 6 from the plug-in socket 9a, 9b is detected by the monitoring system 7. The monitoring system 7 sends a signal about an attempt to remove the plug to the disconnecting module 3 either directly through the wires 8 or indirectly through the wires 8 and the communication modules 10a and 10b. The disconnecting module 3 turns off the current that supplies the connected receiver 5.
Key to the drawing
[0026]
1. AC/DC power supply unit 1
2. electric wires
3. disconnecting module 3
4. contacts
5. receiver
6. plug
6a - pin
7. the monitoring system
7a - the monitoring system in the first embodiment variety
7b - the monitoring system in the second embodiment variety
8. signal wires
9a, 9b - plug-in socket
10a, 10b - communication module
11. casing
12. block
13. sets of contacts
14. magnetic coil
15. magnetic core
16. mechanical block
17. pawl
18. spring
19. block-releasing mechanism
20. block-releasing signal wires
1. A system protecting electric equipment against disconnection from the power supply
network, comprising an AC supply source electrically connected with a central AC/DC
power supply unit (1) fitted with at least one output for electric wires (2) for transmitting
direct current of different voltages and equipped with at least one plug-in socket
(9a, 9b) for switching-on in it household receivers (5) supplied with direct current,
characterized in that it contains a disconnecting module (3) connected into the system between the central
AC/DC power supply unit (1) and the contacts (4) of the plug-in socket (9a,9b) fitted
with a monitoring system (7) which is connected with the disconnecting module (3).
2. A system according to claim 1, characterized in that a mechanical block (16) preventing removal of the plug(6) from the plug-in socket
(9a, 9b) is connected to the system between the contacts (4) and the monitoring system
(7).
3. A system according to claim 1 or 2, characterized in that the disconnecting module (3) is situated in the plug-in socket (9a).
4. A system according to claim 1 or 2, characterized in that the disconnecting module (3) is situated near the central AC/DC power supply unit
(1) and outside the plug-in socket (9b).
5. A system according to claim 4, characterized in that the disconnecting module (3) is connected with the monitoring system (7) through
communication modules (10a,10b) of which one (10a) is located in the plug-in socket
(9b), and the other (10b) near the disconnecting module (3) outside the plug-in socket
(9b).
6. A system according to claim 5, characterized in that the disconnecting module (3), the communication module (10b) and the central AC/DC
power supply unit (1) are located in a common casing (11).
7. A system according to any of the claims 1-6, characterized in that the monitoring system (7) has the form of a coil with a magnetic core.
8. A system according to any of the claims 1-6 characterized in that the monitoring system has the form of an electric circuit with sets of contact (13),
which is electrically connected with the disconnecting module (3).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description