Low-voltage combined external supply multi-loop secondary power supply circuit

Abstract

The embodiment of the utility model provides a low-voltage combined external supply multi-loop secondary power supply circuit. The low-voltage combined external supply multi-loop secondary power supply circuit comprises a self-power supply loop, a first external power supply loop, a second external power supply loop, a contactor 1KA, a contactor 2KA and a contactor 3KA, the system can also comprise a third external power supply loop. When the self-powered power supply loop is used for supplying power, the self-powered power supply loop can supply power to all electric equipment; when the self-powered power supply loop breaks down or needs to be subjected to power-off maintenance, the multiple external power supply loops can supply power to multiple sets of electric equipment respectively, so that the power requirements of more electric equipment are met.

Description

TECHNICAL FIELD

[0001] The utility model relates to an electrical circuit, especially a low-voltage combined external supply multi-loop secondary power supply circuit. BACKGROUND

[0002] The mine underground secondary power supply circuit needs to provide 220v voltage for specific power consumption equipment, which includes electric chassis car, electric grounding knife, liquid crystal screen, cabinet heater, etc.

[0003] The existing secondary power supply circuit usually includes a self-supply power supply loop and an external power supply loop; the self-supply power supply loop includes a power supply transformer with large power, which can meet the power demand of all secondary side power consumption equipment; but once the self-supply power supply loop fails or needs to be powered off for maintenance, the power supply power of the external power supply loop is difficult to meet the power demand of all power consumption equipment. SUMMARY

[0004] In view of the deficiencies in the prior art, the utility model embodiment provides a low-voltage combined external supply multi-loop secondary power supply circuit, when the self-supply power supply loop stops supplying power to the power consumption equipment, the multi-loop external power supply loop can supply power to multiple groups of power consumption equipment respectively, so as to guarantee the power demand of more power consumption equipment. In order to realize the above technical purpose, the utility model embodiment adopts the technical scheme that:

[0005] The utility model embodiment provides a low-voltage combined external supply multi-loop secondary power supply circuit, which comprises a self-supply power supply loop, a first external power supply loop, a second external power supply loop, a contactor 1KA, a contactor 2KA and a contactor 3KA;

[0006] The first output end of the self-supply power supply loop is connected with one end of the contactor 1KA coil, one end of the contactor 2KA coil, one end of the contactor 3KA coil and the first connection of the contactor 1KA normally open contact 1KA-1; the second output end of the self-supply power supply loop is connected with the other end of the contactor 1KA coil, the other end of the contactor 2KA coil, the other end of the contactor 3KA coil and the first connection of the contactor 1KA normally open contact 1KA-1; the other end of the first connection of the contactor 1KA normally open contact 1KA-1 is connected with the first connection of the contactor 2KA normally open contact 2KA-1, and the other end of the second connection of the contactor 1KA normally open contact 1KA-1 is connected with the other end of the second connection of the contactor 2KA normally open contact 2KA-1; the other end of the first connection of the contactor 2KA normally open contact 2KA-1 is connected with the first connection of the contactor 3KA normally open contact 3KA-1, and the other end of the second connection of the contactor 2KA normally open contact 2KA-1 is connected with the first connection of the contactor 3KA normally open contact 3KA-1;

[0007] The other end of the first connection of the contactor 3KA normally open contact 3KA-1 is connected to the first end of the circuit breaker ZK4, the first end of the circuit breaker ZK5 and the first end of the contactor 2KA normally open contact 2KA-5; the other end of the second connection of the contactor 3KA normally open contact 3KA-1 is connected to the first end of the circuit breaker ZK4, the first end of the circuit breaker ZK5 and the first end of the contactor 2KA normally open contact 2KA-5;

[0008] The first external power supply circuit includes the circuit breaker ZK1, the first end and the second end of the circuit breaker ZK1 are used to connect the first external power supply; the other end of the first connection of the circuit breaker ZK1 is connected to the first end of the contactor 1KA normally closed contact 1KA-2, the other end of the first connection of the contactor 1KA normally closed contact 1KA-2 is connected to the first end of the contactor 2KA normally closed contact 2KA-2, the other end of the first connection of the contactor 2KA normally closed contact 2KA-2 is connected to the first end of the contactor 3KA normally closed contact 3KA-2; the other end of the first connection of the contactor 3KA normally closed contact 3KA-2 is connected to the first end of the circuit breaker ZK4; the other end of the second connection of the circuit breaker ZK1 is connected to the first end of the contactor 1KA normally closed contact 1KA-2, the other end of the second connection of the contactor 1KA normally closed contact 1KA-2 is connected to the first end of the contactor 2KA normally closed contact 2KA-2, the other end of the second connection of the contactor 2KA normally closed contact 2KA-2 is connected to the first end of the contactor 3KA normally closed contact 3KA-2; the other end of the second connection of the contactor 3KA normally closed contact 3KA-2 is connected to the first end of the circuit breaker ZK4;

[0009] The second external power supply circuit includes the circuit breaker ZK2, the first end and the second end of the circuit breaker ZK2 are used to connect the second external power supply; the other end of the first connection of the circuit breaker ZK2 is connected to the first end of the contactor 1KA normally closed contact 1KA-3, the other end of the first connection of the contactor 1KA normally closed contact 1KA-3 is connected to the first end of the contactor 2KA normally closed contact 2KA-3, the other end of the first connection of the contactor 2KA normally closed contact 2KA-3 is connected to the first end of the contactor 3KA normally closed contact 3KA-3; the other end of the first connection of the contactor 3KA normally closed contact 3KA-3 is connected to the first end of the circuit breaker ZK4, the first end of the circuit breaker ZK5 and the other end of the first connection of the contactor 2KA normally open contact 2KA-5; the other end of the second connection of the circuit breaker ZK2 is connected to the first end of the contactor 1KA normally closed contact 1KA-3, the other end of the second connection of the contactor 1KA normally closed contact 1KA-3 is connected to the first end of the contactor 2KA normally closed contact 2KA-3, the other end of the second connection of the contactor 2KA normally closed contact 2KA-3 is connected to the first end of the contactor 3KA normally closed contact 3KA-3; the other end of the second connection of the contactor 3KA normally closed contact 3KA-3 is connected to the first end of the circuit breaker ZK4, the first end of the circuit breaker ZK5 and the other end of the second connection of the contactor 2KA normally open contact 2KA-5.

[0010] Further, the low-voltage combined external power supply multi-loop secondary power supply circuit further comprises a third external power supply loop;

[0011] The third external power supply loop comprises a circuit breaker ZK3, and a first end and a second end of a first connection of the circuit breaker ZK3 are used for connecting a third external power supply;

[0012] A first end of a first connection of a normally open contact 2KA-5 of a contactor 2KA is connected to a first end of a first connection of a normally open contact 3KA-5 of a contactor 3KA, and a second end of a first connection of the normally open contact 2KA-5 of the contactor 2KA is connected to a second end of a first connection of the normally open contact 3KA-5 of the contactor 3KA;

[0013] A first end of a first connection of a normally open contact 2KA-5 of a contactor 2KA is connected to a first end of a first connection of a normally open contact 3KA-5 of a contactor 3KA, and a second end of a first connection of the normally open contact 2KA-5 of the contactor 2KA is connected to a second end of a first connection of the normally open contact 3KA-5 of the contactor 3KA;

[0014] A first end of a first connection of a normally open contact 2KA-5 of a contactor 2KA is connected to a first end of a first connection of a normally open contact 3KA-5 of a contactor 3KA, and a second end of a first connection of the normally open contact 2KA-5 of the contactor 2KA is connected to a second end of a first connection of the normally open contact 3KA-5 of the contactor 3KA;

[0015] Further, a power supply voltage of the self-power supply loop is 220v AC.

[0016] Further, a power supply voltage of any external power supply loop is 220v AC.

[0017] The beneficial effects brought by the technical scheme provided by the embodiment of the utility model are as follows: when the self-power supply loop is used for power supply, the self-power supply loop can supply power to all electrical equipment; when the self-power supply loop fails or needs to be powered off for maintenance, the multi-loop external power supply loop can supply power to multiple groups of electrical equipment respectively, so that the power demand of more electrical equipment is guaranteed. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The secondary power supply circuit schematic diagram in the embodiment of the utility model. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] like Figure 1 As shown, an embodiment of the present invention proposes a low-voltage combined external multi-circuit secondary power supply circuit, comprising a self-power supply circuit, a first external power supply circuit, a second external power supply circuit, contactors 1KA, 2KA, and 3KA;

[0021] The first output terminal of the self-power supply circuit is connected to one end of the contactor 1KA coil, one end of the contactor 2KA coil, one end of the contactor 3KA coil and one end of the first connection of the normally open contact 1KA-1 of the contactor 1KA; the second output terminal of the self-power supply circuit is connected to the other end of the contactor 1KA coil, the other end of the contactor 2KA coil, the other end of the contactor 3KA coil and one end of the second connection of the normally open contact 1KA-1 of the contactor 1KA; the other end of the first connection of the normally open contact 1KA-1 of the contactor 1KA is connected to one end of the first connection of the normally open contact 2KA-1 of the contactor 2KA, and the other end of the second connection of the normally open contact 1KA-1 of the contactor 1KA is connected to the other end of the second connection of the normally open contact 2KA-1 of the contactor 2KA; the other end of the first connection of the normally open contact 2KA-1 of the contactor 2KA is connected to one end of the first connection of the normally open contact 3KA-1 of the contactor 3KA, and the other end of the second connection of the normally open contact 2KA-1 of the contactor 2KA is connected to one end of the second connection of the normally open contact 3KA-1 of the contactor 3KA;

[0022] The other end of the first link of the normally open contact 3KA-1 of the contactor 3KA is connected to one end of the first link of the circuit breaker ZK4, one end of the first link of the circuit breaker ZK5, and one end of the first link of the normally open contact 2KA-5 of the contactor 2KA; the other end of the second link of the normally open contact 3KA-1 of the contactor 3KA is connected to one end of the second link of the circuit breaker ZK4, one end of the second link of the circuit breaker ZK5, and one end of the second link of the normally open contact 2KA-5 of the contactor 2KA;

[0023] The first external power supply circuit comprises a circuit breaker ZK1, one end of a first connection and one end of a second connection of the circuit breaker ZK1 are used for connecting a first external power supply; the other end of the first connection of the circuit breaker ZK1 is connected with a first end of a normally closed contact 1KA-2 of a contactor 1KA, the other end of the first connection of the normally closed contact 1KA-2 of the contactor 1KA is connected with a first end of a normally closed contact 2KA-2 of a contactor 2KA, the other end of the first connection of the normally closed contact 2KA-2 of the contactor 2KA is connected with a first end of a normally closed contact 3KA-2 of a contactor 3KA; the other end of the first connection of the normally closed contact 3KA-2 of the contactor 3KA is connected with a first end of a circuit breaker ZK4; the other end of the second connection of the circuit breaker ZK1 is connected with a first end of a normally closed contact 1KA-2 of a contactor 1KA, the other end of the second connection of the normally closed contact 1KA-2 of the contactor 1KA is connected with a first end of a normally closed contact 2KA-2 of a contactor 2KA, the other end of the second connection of the normally closed contact 2KA-2 of the contactor 2KA is connected with a first end of a normally closed contact 3KA-2 of a contactor 3KA; the other end of the second connection of the normally closed contact 3KA-2 of the contactor 3KA is connected with a first end of a circuit breaker ZK4;

[0024] The second external power supply circuit comprises a circuit breaker ZK2, one end of a first connection and one end of a second connection of the circuit breaker ZK2 are used for connecting a second external power supply; the other end of the first connection of the circuit breaker ZK2 is connected with a first end of a normally closed contact 1KA-3 of a contactor 1KA, the other end of the first connection of the normally closed contact 1KA-3 of the contactor 1KA is connected with a first end of a normally closed contact 2KA-3 of a contactor 2KA, the other end of the first connection of the normally closed contact 2KA-3 of the contactor 2KA is connected with a first end of a normally closed contact 3KA-3 of a contactor 3KA; the other end of the first connection of the normally closed contact 3KA-3 of the contactor 3KA is connected with a first end of a circuit breaker ZK4, a first end of a circuit breaker ZK5 and the other end of a first connection of a normally open contact 2KA-5 of the contactor 2KA; the other end of the second connection of the circuit breaker ZK2 is connected with a first end of a normally closed contact 1KA-3 of a contactor 1KA, the other end of the second connection of the normally closed contact 1KA-3 of the contactor 1KA is connected with a first end of a normally closed contact 2KA-3 of a contactor 2KA, the other end of the second connection of the normally closed contact 2KA-3 of the contactor 2KA is connected with a first end of a normally closed contact 3KA-3 of a contactor 3KA; the other end of the second connection of the normally closed contact 3KA-3 of the contactor 3KA is connected with a first end of a circuit breaker ZK4, a first end of a circuit breaker ZK5 and the other end of a second connection of a normally open contact 2KA-5 of the contactor 2KA.

[0025] Further, the low-voltage combined external power supply multi-circuit secondary power supply circuit further comprises a third external power supply circuit.

[0026] The third external power supply circuit comprises a circuit breaker ZK3, one end of a first connection and one end of a second connection of the circuit breaker ZK3 are used for connecting a third external power supply;

[0027] The other end of the first connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the first connection of the contactor 3KA normally open contact 3KA-5; the other end of the second connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the second connection of the contactor 3KA normally open contact 3KA-5.

[0028] The other end of the first connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the first connection of the contactor 3KA normally open contact 3KA-5; the other end of the second connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the second connection of the contactor 3KA normally open contact 3KA-5.

[0029] The other end of the first connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the first connection of the contactor 3KA normally open contact 3KA-5; the other end of the second connection of the contactor 2KA normally open contact 2KA-5 is connected to the one end of the second connection of the contactor 3KA normally open contact 3KA-5.

[0030] The above first connection and the second connection of the circuit breaker ZK4 and the first connection and the second connection of the circuit breaker ZK5 are used for supplying power to the first group of electrical equipment; the third connection and the fourth connection of the circuit breaker ZK4 and the third connection and the fourth connection of the circuit breaker ZK5 are used for supplying power to the second group of electrical equipment; the fifth connection and the sixth connection of the circuit breaker ZK4 and the fifth connection and the sixth connection of the circuit breaker ZK5 are used for supplying power to the third group of electrical equipment.

[0031] In the mine, generally use the self power supply circuit as the main power supply circuit, at this time, the coil of the contactor 1KA, 2KA, 3KA is electrified, the normally open contact 1KA-1 of the contactor 1KA, the normally open contact 2KA-1 of the contactor 2KA, the normally open contact 3KA-1 of the contactor 3KA, the normally open contact 2KA-5 of the contactor 2KA and the normally open contact 3KA-5 of the contactor 3KA are closed; while the normally closed contact 1KA-2 of the circuit breaker 1KA, the normally closed contact 2KA-2 of the circuit breaker 2KA, the normally closed contact 3KA-2 of the circuit breaker 3KA, the normally closed contact 1KA-3 of the circuit breaker 1KA, the normally closed contact 2KA-3 of the circuit breaker 2KA, the normally closed contact 3KA-3 of the circuit breaker 3KA, the normally closed contact 1KA-4 of the circuit breaker 1KA, the normally closed contact 2KA-4 of the circuit breaker 2KA, the normally closed contact 3KA-4 of the circuit breaker 3KA are all disconnected; the self power supply circuit can supply power to all electrical equipment; the power of the power supply transformer in the self power supply circuit is large enough to meet the power demand of all secondary electrical equipment;

[0032] When the self power supply circuit fails or needs to be shut down for maintenance, the coil of the contactor 1KA, 2KA, 3KA loses power; the normally open contact 1KA-1 of the contactor 1KA, the normally open contact 2KA-1 of the contactor 2KA, the normally open contact 3KA-1 of the contactor 3KA, the normally open contact 2KA-5 of the contactor 2KA and the normally open contact 3KA-5 of the contactor 3KA are all disconnected; while the normally closed contact 1KA-2 of the circuit breaker 1KA, the normally closed contact 2KA-2 of the circuit breaker 2KA, the normally closed contact 3KA-2 of the circuit breaker 3KA, the normally closed contact 1KA-3 of the circuit breaker 1KA, the normally closed contact 2KA-3 of the circuit breaker 2KA, the normally closed contact 3KA-3 of the circuit breaker 3KA, the normally closed contact 1KA-4 of the circuit breaker 1KA, the normally closed contact 2KA-4 of the circuit breaker 2KA, the normally closed contact 3KA-4 of the circuit breaker 3KA are all closed; At this time, the first external power supply circuit, the second external power supply circuit and the third external power supply circuit can supply power to the first group of electrical equipment, the second group of electrical equipment and the third group of electrical equipment respectively, avoiding the problem of insufficient power when a single external power supply circuit supplies power to all electrical equipment; multiple external power supply circuits can supply power to multiple groups of electrical equipment respectively to meet the power demand of more electrical equipment.

[0033] Further, the power supply voltage of the self power supply circuit is 220v AC;

[0034] Further, the power supply voltage of any external power supply circuit is 220v AC.

[0035] Finally, it should be explained that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A low voltage combined externally fed multi-loop secondary power supply circuit, characterized in that, The self-supply power circuit, the first external power supply circuit, the second external power supply circuit, the contactor 1KA, the contactor 2KA and the contactor 3KA are connected in series. The first output end of the self-supply power circuit is connected with one end of the contactor 1KA coil, one end of the contactor 2KA coil, one end of the contactor 3KA coil and one end of the first connection of the contactor 1KA normally open contact 1KA-1; the second output end of the self-supply power circuit is connected with the other end of the contactor 1KA coil, the other end of the contactor 2KA coil, the other end of the contactor 3KA coil and one end of the second connection of the contactor 1KA normally open contact 1KA-1; the other end of the first connection of the contactor 1KA normally open contact 1KA-1 is connected with one end of the first connection of the contactor 2KA normally open contact 2KA-1, and the other end of the second connection of the contactor 1KA normally open contact 1KA-1 is connected with the other end of the second connection of the contactor 2KA normally open contact 2KA-1; the other end of the first connection of the contactor 2KA normally open contact 2KA-1 is connected with one end of the first connection of the contactor 3KA normally open contact 3KA-1, and the other end of the second connection of the contactor 2KA normally open contact 2KA-1 is connected with one end of the second connection of the contactor 3KA normally open contact 3KA-1; The other end of the first connection of the contactor 3KA normally open contact 3KA-1 is connected with one end of the first connection of the circuit breaker ZK4, one end of the first connection of the circuit breaker ZK5 and one end of the first connection of the contactor 2KA normally open contact 2KA-5; the other end of the second connection of the contactor 3KA normally open contact 3KA-1 is connected with one end of the second connection of the circuit breaker ZK4, one end of the second connection of the circuit breaker ZK5 and one end of the second connection of the contactor 2KA normally open contact 2KA-5; The first external power supply circuit comprises the circuit breaker ZK1, and the first connection and the second connection of the circuit breaker ZK1 are used for connecting the first external power supply; the other end of the first connection of the circuit breaker ZK1 is connected with one end of the first connection of the contactor 1KA normally closed contact 1KA-2, the other end of the first connection of the contactor 1KA normally closed contact 1KA-2 is connected with one end of the first connection of the contactor 2KA normally closed contact 2KA-2, the other end of the first connection of the contactor 2KA normally closed contact 2KA-2 is connected with one end of the first connection of the contactor 3KA normally closed contact 3KA-2; the other end of the first connection of the contactor 3KA normally closed contact 3KA-2 is connected with one end of the first connection of the circuit breaker ZK4; the other end of the second connection of the circuit breaker ZK1 is connected with one end of the second connection of the contactor 1KA normally closed contact 1KA-2, the other end of the second connection of the contactor 1KA normally closed contact 1KA-2 is connected with one end of the second connection of the contactor 2KA normally closed contact 2KA-2, the other end of the second connection of the contactor 2KA normally closed contact 2KA-2 is connected with one end of the second connection of the contactor 3KA normally closed contact 3KA-2; the other end of the second connection of the contactor 3KA normally closed contact 3KA-2 is connected with one end of the second connection of the circuit breaker ZK4; The second external power supply circuit comprises a circuit breaker ZK2, one end of the first connection and one end of the second connection of the circuit breaker ZK2 are used for connecting the second external power supply; the other end of the first connection of the circuit breaker ZK2 is connected to the first end of the normally closed contact 1KA-3 of the contactor 1KA, the other end of the first connection of the normally closed contact 1KA-3 of the contactor 1KA is connected to the first end of the normally closed contact 2KA-3 of the contactor 2KA, the other end of the first connection of the normally closed contact 2KA-3 of the contactor 2KA is connected to the first end of the normally closed contact 3KA-3 of the contactor 3KA; the other end of the first connection of the normally closed contact 3KA-3 of the contactor 3KA is connected to the first end of the third connection of the circuit breaker ZK4, the first end of the third connection of the circuit breaker ZK5 and the other end of the first connection of the normally open contact 2KA-5 of the contactor 2KA; the other end of the second connection of the circuit breaker ZK2 is connected to the first end of the second connection of the normally closed contact 1KA-3 of the contactor 1KA, the other end of the second connection of the normally closed contact 1KA-3 of the contactor 1KA is connected to the first end of the second connection of the normally closed contact 2KA-3 of the contactor 2KA, the other end of the second connection of the normally closed contact 2KA-3 of the contactor 2KA is connected to the first end of the second connection of the normally closed contact 3KA-3 of the contactor 3KA; the other end of the second connection of the normally closed contact 3KA-3 of the contactor 3KA is connected to the first end of the fourth connection of the circuit breaker ZK4, the first end of the fourth connection of the circuit breaker ZK5 and the other end of the second connection of the normally open contact 2KA-5 of the contactor 2KA.

2. The low-voltage combined external multi-circuit secondary power supply circuit according to claim 1, further comprising a third external power supply circuit; The third external power supply circuit comprises a circuit breaker ZK3, one end of the first connection and one end of the second connection of the circuit breaker ZK3 are used for connecting the third external power supply; The other end of the first connection of the normally open contact 2KA-5 of the contactor 2KA is connected to the first end of the normally open contact 3KA-5 of the contactor 3KA; the other end of the second connection of the normally open contact 2KA-5 of the contactor 2KA is connected to the first end of the second connection of the normally open contact 3KA-5 of the contactor 3KA; The other end of the first connection of the circuit breaker ZK3 is connected to the first end of the first connection of the normally closed contact 1KA-4 of the contactor 1KA, the other end of the first connection of the normally closed contact 1KA-4 of the contactor 1KA is connected to the first end of the first connection of the normally closed contact 2KA-4 of the contactor 2KA, the other end of the first connection of the normally closed contact 2KA-4 of the contactor 2KA is connected to the first end of the first connection of the normally closed contact 3KA-4 of the contactor 3KA; the other end of the first connection of the normally closed contact 3KA-4 of the contactor 3KA is connected to the first end of the fifth connection of the circuit breaker ZK4, the first end of the fifth connection of the circuit breaker ZK5 and the other end of the first connection of the normally open contact 3KA-5 of the contactor 3KA; The other end of the second connection of the circuit breaker ZK3 is connected to the first end of the second connection of the normally closed contact 1KA-4 of the contactor 1KA, the other end of the second connection of the normally closed contact 1KA-4 of the contactor 1KA is connected to the first end of the second connection of the normally closed contact 2KA-4 of the contactor 2KA, the other end of the second connection of the normally closed contact 2KA-4 of the contactor 2KA is connected to the first end of the second connection of the normally closed contact 3KA-4 of the contactor 3KA; the other end of the second connection of the normally closed contact 3KA-4 of the contactor 3KA is connected to the first end of the sixth connection of the circuit breaker ZK4, the first end of the sixth connection of the circuit breaker ZK5 and the other end of the second connection of the normally open contact 3KA-5 of the contactor 3KA. ​ 3. The low voltage combined externally fed multi-circuit secondary supply circuit according to claim 1 or 2, characterized in that, the supply voltage of the self-supply source circuit is 220 V AC.

4. The low voltage combined externally fed multi-circuit secondary supply circuit according to claim 1 or 2, characterized in that, the supply voltage of any externally fed source circuit is 220 V AC.

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