Power switching device

Abstract

The power supply switching device is provided with a main power supply circuit, an auxiliary power supply circuit, a load circuit, a power supply side relay and a load side relay. The power supply side relay is provided with a first main power supply contact, a second main power supply contact, a first auxiliary power supply contact and a second auxiliary power supply contact. The power supply side relay connects the first main power supply contact and the second main power supply contact in a first main connection state, and disconnects the first auxiliary power supply contact and the second auxiliary power supply contact. The power supply side relay connects the first auxiliary power supply contact and the second auxiliary power supply contact in the second main connection state, and disconnects the first main power supply contact and the second main power supply contact. The load side relay is provided with a third main power supply contact and a third auxiliary power supply contact. The load side relay connects the third main power supply contact and the load circuit in the second main connection state, and disconnects the third auxiliary power supply contact and the load circuit. The load side relay connects the third auxiliary power supply contact and the load circuit in the second auxiliary connection state, and disconnects the third main power supply contact and the load circuit.

Description

Technical Field

[0001] The present invention relates to a power supply switching device. Background Art

[0002] There has been conventionally known a power supply switching device for switching the power supply of a load. For example, Patent Document 1 discloses a power supply switching system that switches the power supply of a load from a commercial power supply to another power supply when the commercial power supply fails. This power supply switching system includes first to fourth relays. The a-contact of the first relay is connected to the commercial power supply. The a-contact of the second relay is connected to another power supply. The other power supply includes a storage battery and a distributed power source. The a-contact of the third relay is connected to the storage battery. The a-contact of the fourth relay is connected to the distributed power source. By switching the on / off states of the a-contacts of the first to fourth relays, the power supply connected to the load is switched.

[0003] Prior Art Documents

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-132495

[0005] In the above power supply switching system, a power short circuit occurs when the contacts are welded. For example, in a state where the a-contact of the first relay is welded, if the a-contacts of the second and third relays are switched to the on state, the main power supply and the storage battery are short-circuited. An object of the present invention is to prevent a power short circuit in a power supply switching device that switches between multiple power supplies when the contacts are welded. Summary of the Invention

[0006] A power switching device according to one embodiment of the present invention switches the power supply of a load between a main power supply and an auxiliary power supply. The power switching device includes a main power supply circuit, an auxiliary power supply circuit, a load circuit, a power supply side relay, a main connection circuit, an auxiliary connection circuit, and a load side relay. The main power supply circuit is connected to the main power supply. The auxiliary power supply circuit is connected to the auxiliary power supply. The load circuit is connected to the load. The power supply side relay includes a first main power supply contact, a second main power supply contact, a first auxiliary power supply contact, and a second auxiliary power supply contact. The first main power supply contact is connected to the main power supply circuit. The second main power supply contact is disposed corresponding to the first main power supply contact. The first auxiliary power supply contact is connected to the auxiliary power supply circuit. The second auxiliary power supply contact is disposed corresponding to the first auxiliary power supply contact. The power supply side relay can be switched to a first main connection state and a first auxiliary connection state. In the first main connection state, the power supply side relay connects the first main power supply contact and the second main power supply contact, and disconnects the first auxiliary power supply contact and the second auxiliary power supply contact. In the second main connection state, the power supply side relay connects the first auxiliary power supply contact and the second auxiliary power supply contact, and disconnects the first main power supply contact and the second main power supply contact. The main connection circuit is connected to the second main power supply contact. The auxiliary connection circuit is connected to the second auxiliary power supply contact. The load side relay includes a third main power supply contact and a third auxiliary power supply contact. The third main power supply contact is connected to the main connection circuit. The third auxiliary power supply contact is connected to the auxiliary connection circuit. The load side relay can be switched to a second main connection state and a second auxiliary connection state. In the second main connection state, the load side relay connects the third main power supply contact and the load circuit, and disconnects the third auxiliary power supply contact and the load circuit. In the second auxiliary connection state, the load side relay connects the third auxiliary power supply contact and the load circuit, and disconnects the third main power supply contact and the load circuit.

[0007] In the power switching device of this embodiment, when a contact fusion occurs in the power supply side relay, the power supply side relay cannot be switched between the first main connection state and the first auxiliary connection state, but the load side relay can be switched to the second main connection state and the second auxiliary connection state. In addition, when a contact fusion occurs in the load side relay, the load side relay cannot be switched between the second main connection state and the second auxiliary connection state, but the power supply side relay can be switched to the first main connection state and the first auxiliary connection state. Thus, a short circuit of the power supply is prevented.

[0008] The power switching device may further include a controller that controls the power supply side relay and the load side relay. The controller may supply power from the main power supply to the load by switching the power supply side relay to the first main connection state and switching the load side relay to the second main connection state.

[0009] The controller can also switch the load-side relay to the second main connection state after a specified time has elapsed after switching the power-side relay to the first main connection state. In this case, the generation of an arc in the power-side relay can be suppressed. The controller can also switch the power-side relay to the first main connection state after a specified time has elapsed after switching the load-side relay to the second main connection state. In this case, the generation of an arc in the load-side relay can be suppressed.

[0010] The controller can also supply power to the load from the auxiliary power source by switching the power-side relay to the first auxiliary connection state and the load-side relay to the second auxiliary connection state. The controller can also switch the load-side relay to the second auxiliary connection state after a specified time has elapsed after switching the power-side relay to the first auxiliary connection state. In this case, the generation of an arc in the power-side relay can be suppressed. The controller can also switch the power-side relay to the first auxiliary connection state after a specified time has elapsed after switching the load-side relay to the second auxiliary connection state. In this case, the generation of an arc in the load-side relay can be suppressed.

[0011] The power switching device may further include a main power sensor that detects the voltage or current of the main power circuit. The controller can also determine the welding of at least one of the first main power contact, the second main power contact, and the third main power contact based on the voltage or current of the main power circuit detected by the main power sensor. In this case, the occurrence of the welding of the contact can be detected.

[0012] The power switching device may further include an auxiliary power sensor that detects the voltage or current of the auxiliary power circuit. The controller can also determine the welding of at least one of the first auxiliary power contact, the second auxiliary power contact, and the third auxiliary power contact based on the voltage or current of the auxiliary power circuit detected by the auxiliary power sensor. In this case, the occurrence of the welding of the contact can be detected.

[0013] According to the present invention, in a power switching device that switches between multiple power sources, in the case of contact welding, a short circuit of the power source can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram showing the structure of the power switching device.

[0015] Figure 2 is an enlarged view of the power switching device in the main connection state.

[0016] Figure 3 is an enlarged view of the power switching device in the auxiliary connection state.

[0017] Figure 4It is a schematic diagram showing the structure of the power supply switching device.

[0018] Figure 5 It is a timing diagram showing the control of the power supply side relay and the load side relay during the switching of the power supply.

[0019] Figure 6 It is a diagram showing the connection state of the power supply of the power supply switching device when contact welding occurs in the first power supply side relay.

[0020] Figure 7 It is a diagram showing the power supply switching device of the first modification example.

[0021] Figure 8 It is a diagram showing the power supply switching device of the second modification example.

[0022] Figure 9 It is a diagram showing the power supply switching device of the third modification example.

[0023] Figure 10 It is a diagram showing the power supply switching device of the fourth modification example. Detailed implementation mode

[0024] Hereinafter, the power supply switching device of the implementation mode will be described with reference to the drawings. Figure 1 It is a schematic diagram showing the structure of the power supply switching device 1 of the implementation mode. As Figure 1 shown, the power supply switching device 1 is connected to the loads L1 - L3, the main power supply P1, and the auxiliary power supply P2. The main power supply P1 is, for example, a commercial power supply. The auxiliary power supply P2 is used in place of the main power supply P1 when the main power supply P1 is out of power. The auxiliary power supply P2 is, for example, a battery or a generator. The loads L1 - L3 are electrical devices supplied with power from the main power supply P1 or the auxiliary power supply P2. The power supply switching device 1 switches the power supply of the loads L1 - L3 between the main power supply P1 and the auxiliary power supply P2.

[0025] The power supply switching device 1 includes main power supply circuits 2A - 2C, auxiliary power supply circuits 3A - 3C, load circuits 4A - 4C, power supply side relays 5A - 5C, main connection circuits 6A - 6C, auxiliary connection circuits 7A - 7C, load side relays 8A - 8C, and a controller 9. The main power supply circuits 2A - 2C are connected to the main power supply P1. The main power supply circuits 2A - 2C include a first main power supply circuit 2A, a second main power supply circuit 2B, and a third main power supply circuit 2C. The auxiliary power supply circuits 3A - 3C are connected to the auxiliary power supply P2. The auxiliary power supply circuits 3A - 3C include a first auxiliary power supply circuit 3A, a second auxiliary power supply circuit 3B, and a third auxiliary power supply circuit 3C. The load circuits 4A - 4C are connected to the loads L1 - L3. The load circuits 4A - 4C include a first load circuit 4A, a second load circuit 4B, and a third load circuit 4C.

[0026] The power supply side relays 5A - 5C are connected to the main power supply circuit 2A - 2C and the auxiliary power supply circuit 3A - 3C. The power supply side relays 5A - 5C include a first power supply side relay 5A, a second power supply side relay 5B, and a third power supply side relay 5C. The first power supply side relay 5A to the third power supply side relay 5C each have a contact structure of type 1a1b. The first power supply side relay 5A is connected to the first main power supply circuit 2A and the first auxiliary power supply circuit 3A. The second power supply side relay 5B is connected to the second main power supply circuit 2B and the second auxiliary power supply circuit 3B. The third power supply side relay 5C is connected to the third main power supply circuit 2C and the third auxiliary power supply circuit 3C.

[0027] Figure 2 It is an enlarged view of the power supply switching device 1. As Figure 2 shown, the first power supply side relay 5A includes a first main power supply contact 11A, a second main power supply contact 12A, a first auxiliary power supply contact 13A, a second auxiliary power supply contact 14A, a first movable piece 15A, and a first coil 16A. The first main power supply contact 11A is connected to the first main power supply circuit 2A. The second main power supply contact 12A is arranged corresponding to the first main power supply contact 11A. The first auxiliary power supply contact 13A is connected to the first auxiliary power supply circuit 3A. The second auxiliary power supply contact 14A is arranged corresponding to the first auxiliary power supply contact 13A.

[0028] The first movable piece 15A can move to Figure 2 the main connection position shown in Figure 3 and Figure 2 the auxiliary connection position shown in Figure 3 As shown, the first movable piece 15A connects the first main power supply contact 11A and the second main power supply contact 12A at the main connection position, and disconnects the first auxiliary power supply contact 13A and the second auxiliary power supply contact 14A. As

[0029] The first power supply side relay 5A can switch between the main connection state and the auxiliary connection state. By arranging the first movable piece 15A at the main connection position, the first power supply side relay 5A becomes the main connection state. In the main connection state, the first power supply side relay 5A connects the first main power contact 11A and the second main power contact 12A, and disconnects the first auxiliary power contact 13A and the second auxiliary power contact 14A. By arranging the first movable piece 15A at the auxiliary connection position, the first power supply side relay 5A becomes the auxiliary connection state. In the auxiliary connection state, the first power supply side relay 5A connects the first auxiliary power contact 13A and the second auxiliary power contact 14A, and disconnects the first main power contact 11A and the second main power contact 12A.

[0030] The second power supply side relay 5B and the third power supply side relay 5C have the same structure as the first power supply side relay 5A. Specifically, the second power supply side relay 5B includes a first main power contact 11B, a second main power contact 12B, a first auxiliary power contact 13B, a second auxiliary power contact 14B, a first movable piece 15B, and a first coil 16B. The first main power contact 11B, the second main power contact 12B, the first auxiliary power contact 13B, the second auxiliary power contact 14B, the first movable piece 15B, and the first coil 16B of the second power supply side relay 5B are respectively the same as the first main power contact 11A, the second main power contact 12A, the first auxiliary power contact 13A, the second auxiliary power contact 14A, the first movable piece 15A, and the first coil 16A of the first power supply side relay 5A.

[0031] The third power supply side relay 5C includes a first main power contact 11C, a second main power contact 12C, a first auxiliary power contact 13C, a second auxiliary power contact 14C, a first movable piece 15C, and a first coil 16C. The first main power contact 11C, the second main power contact 12C, the first auxiliary power contact 13C, the second auxiliary power contact 14C, the first movable piece 15C, and the first coil 16C of the third power supply side relay 5C are respectively the same as the first main power contact 11A, the second main power contact 12A, the first auxiliary power contact 13A, the second auxiliary power contact 14A, the first movable piece 15A, and the first coil 16A of the first power supply side relay 5A.

[0032] The main connection circuits 6A - 6C and the auxiliary connection circuits 7A - 7C connect the power - side relays 5A - 5C and the load - side relays 8A - 8C respectively. The main connection circuits 6A - 6C include a first main connection circuit 6A, a second main connection circuit 6B, and a third main connection circuit 6C. The auxiliary connection circuits 7A - 7C include a first auxiliary connection circuit 7A, a second auxiliary connection circuit 7B, and a third auxiliary connection circuit 7C. The first main connection circuit 6A and the first auxiliary connection circuit 7A are connected to the first power - side relay 5A. The second main connection circuit 6B and the second auxiliary connection circuit 7B are connected to the second power - side relay 5B. The third main connection circuit 6C and the third auxiliary connection circuit 7C are connected to the third power - side relay 5C.

[0033] Specifically, the first main connection circuit 6A is connected to the second main power contact 12A of the first power - side relay 5A. The second main connection circuit 6B is connected to the second main power contact 12B of the second power - side relay 5B. The third main connection circuit 6C is connected to the second main power contact 12C of the third power - side relay 5C. The first auxiliary connection circuit 7A is connected to the second auxiliary power contact 14A of the first power - side relay 5A. The second auxiliary connection circuit 7B is connected to the second auxiliary power contact 14B of the second power - side relay 5B. The third auxiliary connection circuit 7C is connected to the second auxiliary power contact 14C of the third power - side relay 5C.

[0034] The load - side relays 8A - 8C are connected to the load circuits 4A - 4C respectively. The load - side relays 8A - 8C include a first load - side relay 8A, a second load - side relay 8B, and a third load - side relay 8C. The first load - side relay 8A to the third load - side relay 8C each have a contact structure of type 1a1b.

[0035] The first main connection circuit 6A and the first auxiliary connection circuit 7A are connected to the first load - side relay 8A. The first load - side relay 8A is connected to the first load circuit 4A. The second main connection circuit 6B and the second auxiliary connection circuit 7B are connected to the second load - side relay 8B. The second load - side relay 8B is connected to the second load circuit 4B. The third main connection circuit 6C and the third auxiliary connection circuit 7C are connected to the third load - side relay 8C. The third load - side relay 8C is connected to the third load circuit 4C.

[0036] The first load-side relay 8A includes a third main power contact 21A, a fourth main power contact 22A, a third auxiliary power contact 23A, a fourth auxiliary power contact 24A, a second movable piece 25A, and a second coil 26A. The third main power contact 21A is connected to the first main connection circuit 6A. The fourth main power contact 22A is arranged corresponding to the third main power contact 21A. The fourth main power contact 22A is connected to the first load circuit 4A. The third auxiliary power contact 23A is connected to the first auxiliary connection circuit 7A. The fourth auxiliary power contact 24A is arranged corresponding to the third auxiliary power contact 23A. The fourth auxiliary power contact 24A is connected to the first load circuit 4A.

[0037] The second movable piece 25A can move to Figure 2 the main connection position shown and Figure 3 the auxiliary connection position shown. As Figure 2 shown, the second movable piece 25A connects the third main power contact 21A and the fourth main power contact 22A at the main connection position and disconnects the third auxiliary power contact 23A and the fourth auxiliary power contact 24A. As Figure 3 shown, at the auxiliary connection position, the second movable piece 25A connects the third auxiliary power contact 23A and the fourth auxiliary power contact 24A and disconnects the third main power contact 21A and the fourth main power contact 22A. The second coil 26A moves the second movable piece 25A to the main connection position and the auxiliary connection position by magnetic force.

[0038] The first load-side relay 8A can be switched to the main connection state and the auxiliary connection state. By arranging the second movable piece 25A at the main connection position, the first load-side relay 8A becomes the main connection state. The first load-side relay 8A connects the third main power contact 21A and the fourth main power contact 22A and disconnects the third auxiliary power contact 23A and the fourth auxiliary power contact 24A in the main connection state. By arranging the second movable piece 25A at the auxiliary connection position, the first load-side relay 8A becomes the auxiliary connection state. The first load-side relay 8A connects the third auxiliary power contact 23A and the fourth auxiliary power contact 24A and disconnects the third main power contact 21A and the fourth main power contact 22A in the auxiliary connection state.

[0039] The second load-side relay 8B and the third load-side relay 8C have the same structure as the first load-side relay 8A. Specifically, the second load-side relay 8B includes a third main power contact 21B, a fourth main power contact 22B, a third auxiliary power contact 23B, a fourth auxiliary power contact 24B, a second movable piece 25B, and a second coil 26B. The third main power contact 21B, the fourth main power contact 22B, the third auxiliary power contact 23B, the fourth auxiliary power contact 24B, the second movable piece 25B, and the second coil 26B of the second load-side relay 8B are the same as the third main power contact 21A, the fourth main power contact 22A, the third auxiliary power contact 23A, the fourth auxiliary power contact 24A, the second movable piece 25A, and the second coil 26A of the first load-side relay 8A, respectively.

[0040] The third load-side relay 8C includes a third main power contact 21C, a fourth main power contact 22C, a third auxiliary power contact 23C, a fourth auxiliary power contact 24C, a second movable piece 25C, and a second coil 26C. The third main power contact 21C, the fourth main power contact 22C, the third auxiliary power contact 23C, the fourth auxiliary power contact 24C, the second movable piece 25C, and the second coil 26C of the third load-side relay 8C are the same as the third main power contact 21A, the fourth main power contact 22A, the third auxiliary power contact 23A, the fourth auxiliary power contact 24A, the second movable piece 25A, and the second coil 26A of the first load-side relay 8A, respectively.

[0041] The controller 9 controls the power-side relays 5A-5C and the load-side relays 8A-8C. The controller 9 includes, for example, a processor and a memory. The controller 9 outputs command signals to the first coils 16A-16C of the first power-side relay 5A to the third power-side relay 5C. Thereby, the controller 9 controls the first power-side relay 5A to the third power-side relay 5C, respectively. The controller 9 outputs command signals to the second coils 26A-26C of the first load-side relay 8A to the third load-side relay 8C. Thereby, the controller 9 controls the first load-side relay 8A to the third load-side relay 8C, respectively.

[0042] As Figure 1As shown, the controller 9 sets the power supply side relays 5A - 5C to the main connection state and sets the load side relays 8A - 8C to the main connection state, thereby connecting the main power supply P1 to the loads L1 - L3 and disconnecting the auxiliary power supply P2 from the loads L1 - L3. Specifically, in the main connection state, the first power supply side relay 5A to the third power supply side relay 5C connect the first main power supply circuit 2A to the third main power supply circuit 2C to the first main connection circuit 6A to the third main connection circuit 6C respectively. In the main connection state, the first load side relay 8A to the third load side relay 8C connect the first main connection circuit 6A to the third main connection circuit 6C to the first load circuit 4A to the third load circuit 4C respectively. Thus, the first main power supply circuit 2A to the third main power supply circuit 2C are respectively connected to the first load circuit 4A to the third load circuit 4C, and power is supplied from the main power supply P1 to the loads L1 - L3.

[0043] As Figure 4 shown, the controller 9 switches the power supply side relays 5A - 5C to the auxiliary connection state respectively and switches the load side relays 8A - 8C to the auxiliary connection state respectively, thereby connecting the auxiliary power supply P2 to the loads L1 - L3 and disconnecting the main power supply P1 from the loads L1 - L3. Specifically, as Figure 4 shown, in the auxiliary connection state, the first power supply side relay 5A to the third power supply side relay 5C connect the first auxiliary power supply circuit 3A to the third auxiliary power supply circuit 3C to the first auxiliary connection circuit 7A to the third auxiliary connection circuit 7C respectively. In the auxiliary connection state, the first load side relay 8A to the third load side relay 8C connect the first auxiliary connection circuit 7A to the third auxiliary connection circuit 7C to the first load circuit 4A to the third load circuit 4C respectively. Thus, the first auxiliary power supply circuit 3A to the third auxiliary power supply circuit 3C are respectively connected to the first load circuit 4A to the third load circuit 4C, and power is supplied from the auxiliary power supply P2 to the loads L1 - L3.

[0044] When the main power supply P1 is out of power, the controller 9 switches the power supply of the loads L1 - L3 from the main power supply P1 to the auxiliary power supply P2. When the main power supply P1 is restored, the controller 9 switches the power supply of the loads L1 - L3 from the auxiliary power supply P2 to the main power supply P1. Figure 5 is a timing diagram showing the control of the power supply side relays 5A - 5C and the load side relays 8A - 8C during the power supply switching.

[0045] As Figure 5 shown, at time T0, the main power supply P1 is in the powered - on state, and the controller 9 sets the power supply side relays 5A - 5C and the load side relays 8A - 8C to the main connection state. Thus, power is supplied from the main power supply P1 to the loads L1 - L3 via the main power supply circuits 2A - 2C, the main connection circuits 6A - 6C, and the load circuits 4A - 4C.

[0046] At time T1, if the main power supply P1 loses power, the controller 9 switches the power-side relays 5A - 5C from the main connection state to the auxiliary connection state at time T2. After the controller 9 switches the power-side relays 5A - 5C to the auxiliary connection state, after a specified time t1 has elapsed, it switches the load-side relays 8A - 8C to the auxiliary connection state at time T3. Thereby, power is supplied from the auxiliary power supply P2 to the loads L1 - L3 via the auxiliary power supply circuits 3A - 3C, the auxiliary connection circuits 7A - 7C, and the load circuits 4A - 4C.

[0047] At time T4, if the main power supply P1 resumes power-on, the controller 9 switches the power-side relays 5A - 5C from the auxiliary connection state to the main connection state at time T5. After the controller 9 switches the power-side relays 5A - 5C to the main connection state, after a specified time t2 has elapsed, it switches the load-side relays 8A - 8C to the main connection state at time T6. Thereby, power is supplied from the main power supply P1 to the loads L1 - L3 via the main power supply circuits 2A - 2C, the main connection circuits 6A - 6C, and the load circuits 4A - 4C. In addition, the specified time t2 can be the same as the specified time t1, or it can be different.

[0048] In the power supply switching device 1 of the present embodiment described above, a short circuit of the power supply in the case of contact welding is prevented. For example, as Figure 6 shown, when the main power supply P1 resumes power, in the case where the first auxiliary power contact 13A of the first power-side relay 5A is welded, the second power-side relay 5B, the third power-side relay 5C, and the first load-side relay 8A to the third load-side relay 8C are switched to the main connection state, but the first power-side relay 5A is not switched to the main connection state. In this case, the second main power supply circuit 2B and the third main power supply circuit 2C are respectively connected to the second load circuit 4B and the third load circuit 4C, but the first main power supply circuit 2A is not connected to the first load circuit 4A. However, the first load-side relay 8A is switched to the main connection state, and the first load-side relay 8A disconnects the first auxiliary connection circuit 7A from the first load circuit 4A. Therefore, the first auxiliary power supply circuit 3A is cut off from the first load circuit 4A, thus preventing a short circuit between the main power supply P1 and the auxiliary power supply P2. In the case where the second power-side relay 5B, the third power-side relay 5C, or the first load-side relay 8A to the third load-side relay 8C is welded, a short circuit between the main power supply P1 and the auxiliary power supply P2 is similarly prevented.

[0049] After the controller 9 switches the power-side relays 5A - 5C to the auxiliary connection state, after a specified time t1, it switches the load-side relays 8A - 8C to the auxiliary connection state. Additionally, after the controller 9 switches the power-side relays 5A - 5C to the main connection state, after a specified time t2, it switches the load-side relays 8A - 8C to the main connection state. Thereby, the generation of arcs in the power-side relays 5A - 5C can be suppressed.

[0050] As described above, one embodiment of the present invention has been explained, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention.

[0051] The above-described main power supply P1 and auxiliary power supply P2 are single-phase three-wire AC power supplies. However, the main power supply P1 and the auxiliary power supply P2 can also be three-phase three-wire. Or, as Figure 7 shown, the main power supply P1 and the auxiliary power supply P2 can also be single-phase two-wire. In addition, the second power-side relay 5B and the second load-side relay 8B can be omitted. The main power supply P1 is not limited to a commercial power supply and can also be other power supplies such as a storage battery or a generator.

[0052] The controller 9 can also switch the power-side relays 5A - 5C to the main connection state after a specified time after switching the load-side relays 8A - 8C to the main connection state. The controller 9 can also switch the power-side relays 5A - 5C to the auxiliary connection state after a specified time after switching the load-side relays 8A - 8C to the auxiliary connection state. In this case, the generation of arcs in the load-side relays 8A - 8C can be suppressed.

[0053] The structure of the power supply switching device 1 is not limited to the above-described embodiment and can also be changed. For example, the controller 9 can be omitted. For example, an instruction signal can be input to the power-side relays 5A - 5C and the load-side relays 8A - 8C by manually pressing a switch. Thereby, the connection states of the power-side relays 5A - 5C and the load-side relays 8A - 8C can also be switched.

[0054] As Figure 8As shown, the power supply switching device 1 may also include main power sensors 31A - 31C and auxiliary power sensors 32A - 32C. The main power sensors 31A - 31C respectively detect the voltages of the main power circuits 2A - 2C. The controller 9 determines the welding of any one of the first main power contacts 11A, the second main power contacts 12A, the third main power contacts 21A, and the fourth main power contacts 22A based on the voltage of the first main power circuit 2A detected by the main power sensor 31A. The controller 9 determines the welding of any one of the first main power contacts 11B, the second main power contacts 12B, the third main power contacts 21B, and the fourth main power contacts 22B based on the voltage of the second main power circuit 2B detected by the main power sensor 31B. The controller 9 determines the welding of any one of the first main power contacts 11C, the second main power contacts 12C, the third main power contacts 21C, and the fourth main power contacts 22C based on the voltage of the third main power circuit 2C detected by the main power sensor 31C. In addition, the main power sensors 31A - 31C may also respectively detect the currents of the main power circuits 2A - 2C. The controller 9 may also determine the welding based on the currents of the main power circuits 2A - 2C detected by the main power sensors 31A - 31C.

[0055] The auxiliary power sensors 32A - 32C respectively detect the voltages of the auxiliary power circuits 3A - 3C. The controller 9 determines the welding of any one of the first auxiliary power contacts 13A, the second auxiliary power contacts 14A, the third auxiliary power contacts 23A, and the fourth auxiliary power contacts 24A based on the voltage of the first auxiliary power circuit 3A detected by the auxiliary power sensor 32A. The controller 9 determines the welding of any one of the first auxiliary power contacts 13B, the second auxiliary power contacts 14B, the third auxiliary power contacts 23B, and the fourth auxiliary power contacts 24B based on the voltage of the second auxiliary power circuit 3B detected by the auxiliary power sensor 32B. The controller 9 determines the welding of any one of the first auxiliary power contacts 13C, the second auxiliary power contacts 14C, the third auxiliary power contacts 23C, and the fourth auxiliary power contacts 24C based on the voltage of the third auxiliary power circuit 3C detected by the auxiliary power sensor 32C. Additionally, the auxiliary power sensors 32A - 32C may also respectively detect the currents of the auxiliary power circuits 3A - 3C. The controller 9 may also determine the welding based on the currents of the auxiliary power circuits 3A - 3C detected by the auxiliary power sensors 32A - 3C.

[0056] The controller 9 may also output an alarm when it is determined that welding has occurred in any one of the main power contacts or the auxiliary power contacts. The alarm is, for example, displayed on a display. Or, the alarm may also be output by other means such as the lighting of a lamp. Or the controller 9 may also prohibit the switching of the power supply when it is determined that welding has occurred in any one of the main power contacts or the auxiliary power contacts.

[0057] The structures of the power supply side relays 5A - 5C and the load side relays 8A - 8C are not limited to the above - described embodiments and can also be changed. For example, in the above - described embodiments, the power supply side relays 5A - 5C and the load side relays 8A - 8C have a 1a1b - type contact structure. However, as Figure 9 shown, the power supply side relay 5A and the load side relay 8A can also have a 3a3b - type contact structure. Or, as Figure 10 shown, the load side relays 8A - 8C can also have a 1c - type contact structure. In the above - described embodiments, the relay has a double - break - type contact structure. However, the relay can also have a single - break - type contact structure. The contact can be separated from the movable piece or can also be a part of the movable piece.

[0058] [Industrial Applicability]

[0059] According to the present invention, in a power supply switching device for switching multiple power supplies, in the case of contact welding, a short - circuit of the power supply can be prevented.

[0060] Explanation of Reference Numerals:

[0061] 1... Power supply switching device; 2A... First main power circuit; 3A... First auxiliary power circuit; 4A... First load circuit; 5A... First power supply side relay; 6A... First main connection circuit; 7A... First auxiliary connection circuit; 8A... First load side relay; 9... Controller; 11A... First main power contact; 12A... Second main power contact; 13A... First auxiliary power contact; 14A... Second auxiliary power contact; 21A... Third main power contact; 23A... Third auxiliary power contact; 31A... Main power sensor; 32A... Auxiliary power sensor; L1 - L3... Load; P1... Main power supply; P2... Auxiliary power supply.

Claims

1. A power supply switching device that switches the power supply of a load between a main power supply and an auxiliary power supply, characterized in that, Comprising: A main power circuit connected to the main power supply; An auxiliary power circuit connected to the auxiliary power supply; A load circuit connected to the load; A power supply side relay, which includes: a first main power contact connected to the main power circuit; a second main power contact arranged corresponding to the first main power contact; a first auxiliary power contact connected to the auxiliary power circuit; and a second auxiliary power contact arranged corresponding to the first auxiliary power contact. The power supply side relay can be switched to a first main connection state and a first auxiliary connection state. The first main connection state is a state where the first main power contact is connected to the second main power contact and the first auxiliary power contact is disconnected from the second auxiliary power contact. The first auxiliary connection state is a state where the first auxiliary power contact is connected to the second auxiliary power contact and the first main power contact is disconnected from the second main power contact; A main connection circuit connected to the second main power contact; An auxiliary connection circuit connected to the second auxiliary power contact; and A load side relay, which includes a third main power contact connected to the main connection circuit and a third auxiliary power contact connected to the auxiliary connection circuit. The load side relay can be switched to a second main connection state and a second auxiliary connection state. The second main connection state is a state where the third main power contact is connected to the load circuit and the third auxiliary power contact is disconnected from the load circuit. The second auxiliary connection state is a state where the third auxiliary power contact is connected to the load circuit and the third main power contact is disconnected from the load circuit.

2. The power supply switching device according to claim 1, wherein It further comprises a controller for controlling the power supply side relay and the load side relay.

3. The power supply switching device according to claim 2, wherein The controller switches the power supply side relay to the first main connection state and switches the load side relay to the second main connection state, thereby supplying power from the main power supply to the load.

4. The power supply switching device according to claim 3, wherein After switching the power supply side relay to the first main connection state, the controller switches the load side relay to the second main connection state after a specified time.

5. The power supply switching device according to claim 3, wherein After switching the load side relay to the second main connection state, the controller switches the power supply side relay to the first main connection state after a specified time.

6. The power supply switching device according to claim 2, wherein The controller switches the power supply side relay to the first auxiliary connection state and switches the load side relay to the second auxiliary connection state, thereby supplying power from the auxiliary power supply to the load.

7. The power supply switching device according to claim 6, wherein After the controller switches the power-side relay to the first auxiliary connection state, it switches the load-side relay to the second auxiliary connection state after a specified time.

8. The power supply switching device according to claim 6, wherein: After the controller switches the load-side relay to the second auxiliary connection state, it switches the power-side relay to the first auxiliary connection state after a specified time.

9. The power supply switching device according to claim 2, wherein: It further includes a main power supply sensor for detecting the voltage or current of the main power supply circuit. Based on the voltage or current of the main power supply circuit detected by the main power supply sensor, the controller determines the welding of at least one of the first main power supply contact, the second main power supply contact, and the third main power supply contact.

10. The power supply switching device according to claim 2, wherein: The power supply switching device further includes an auxiliary power supply sensor for detecting the voltage or current of the auxiliary power supply circuit. Based on the voltage or current of the auxiliary power supply circuit detected by the auxiliary power supply sensor, the controller determines the welding of at least one of the first auxiliary power supply contact, the second auxiliary power supply contact, and the third auxiliary power supply contact.

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