Electromagnetic switch fault detection structure

Abstract

This invention provides a fault detection structure for an electromagnetic switch that allows for easy identification of the type of fault that occurs in relation to the movable contacts of the electromagnetic switch. [Solution] The fault detection structure of the electromagnetic switch 1 comprises a pair of terminals 2 having a first terminal 2a located upstream in the direction of current flow and a second terminal 2b located downstream; a movable contact 3 connectable between the pair of terminals 2 to conduct current between the pair of terminals 2; a coil 4 that generates a magnetic force such that the movable contact 3 is connected to the pair of terminals 2 when energized; a first lighting unit 5 connected to the coil 4 and lit depending on whether the coil 4 is energized or not; and a second lighting unit 6 connected to the second terminal 2b and lit depending on whether the second terminal 2b is energized or not. The combination of lighting patterns of the first lighting unit 5 and the second lighting unit 6 is set to differ according to at least the type of fault that may occur in relation to the movable contact 3.

Description

Technical Field

[0001] The present invention relates to a failure discrimination structure of an electromagnetic switch that can easily discriminate the types of failures occurring in relation to the movable contact of the electromagnetic switch.

Background Art

[0002] Conventionally, there is a known technique for checking for disconnection of an electromagnetic coil by connecting a light-emitting element to the coil terminal of the electromagnetic coil and checking whether the light-emitting element emits light when the operation display piece is manually operated to move the movable block (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an electromagnetic switch, in addition to disconnection, there can occur a plurality of types of failures such as contact welding (a phenomenon in which the movable contact is welded to the terminal and does not separate) and contact jamming (a phenomenon in which there is an abnormality in the movable contact and it cannot be closed). Since the location to be repaired varies depending on the type of failure, there is a desire to easily grasp where the failure has occurred.

[0005] Therefore, an object of the present invention is to provide a failure discrimination structure of an electromagnetic switch that can easily discriminate the types of failures occurring in relation to the movable contact of the electromagnetic switch.

Means for Solving the Problems

[0006] The present invention provides a fault detection structure for an electromagnetic switch, comprising: a pair of terminals having a first terminal arranged upstream in the direction of current flow and a second terminal arranged downstream; a movable contact connectable between the pair of terminals to conduct current between them; a coil that generates a magnetic force such that the movable contact is connected to the pair of terminals when energized; a first lighting unit connected to the coil and lit depending on whether the coil is energized or not; and a second lighting unit connected to the second terminal and lit depending on whether the second terminal is energized or not, wherein the combination of lighting patterns of the first lighting unit and the second lighting unit is set to differ according to at least the type of fault that may occur in relation to the movable contact.

[0007] With this configuration, if the user is informed in advance of the fault locations corresponding to the combination of lighting patterns of the first and second lighting units, the user will be able to easily determine "which part of the electromagnetic switch 1 is malfunctioning" when a malfunction actually occurs. [Effects of the Invention]

[0008] According to the fault detection structure for electromagnetic switches of the present invention, it is possible to easily determine the type of fault that has occurred in relation to the movable contacts of the electromagnetic switch. [Brief explanation of the drawing]

[0009] [Figure 1] Circuit diagram of a fault detection structure for an electromagnetic switch according to an embodiment of the present invention [Figure 2] Diagram illustrating combinations of lighting patterns according to the type of malfunction according to an embodiment of the present invention. [Figure 3] Circuit diagram of a fault detection structure for an electromagnetic switch according to a modified example of the present invention. [Figure 4] Diagram illustrating combinations of lighting patterns according to the type of failure, based on a modified version of the present invention. [Figure 5] Circuit diagram of a fault detection structure for an electromagnetic switch according to a modified example of the present invention. [Modes for carrying out the invention]

[0010] The fault detection structure for an electromagnetic switch according to an embodiment of the present invention will be described below with reference to Figures 1 and 2.

[0011] As shown in Figure 1, the electromagnetic switch 1 comprises a pair of terminals 2, a movable contact 3, a coil 4, a first lighting unit 5, a second lighting unit 6, and a thermoswitch 7.

[0012] The pair of terminals 2 comprises a first terminal 2a located on the upstream side in the direction of current flow, and a second terminal 2b located on the downstream side.

[0013] The movable contact 3 can be connected between the pair of terminals 2 to conduct electricity between them.

[0014] When energized, coil 4 generates a magnetic force that causes the movable contact 3 to connect to the pair of terminals 2. In this embodiment, a magnetic force is generated at a fixed contact provided on the coil 4 side, and this magnetic force attracts the movable contact 3, connecting it to the pair of terminals 2. In this embodiment, the user operates an operation switch or the like to instruct the electromagnetic switch 1 to operate, and when the operation of the electromagnetic switch 1 is instructed, coil 4 is energized.

[0015] In this embodiment, power is supplied independently to the first terminal 2a and the coil 4.

[0016] The first lighting unit 5 is connected to the coil 4 and lights up depending on whether the coil 4 is energized or not. In this embodiment, the first lighting unit 5 is connected in series with the coil 4 and lights up when the coil 4 is energized.

[0017] The second lighting unit 6 is connected to the second terminal 2b and lights up depending on whether or not the second terminal 2b is energized. In this embodiment, it lights up when the second terminal 2b is energized.

[0018] As the first lighting unit 5 and the second lighting unit 6, it is conceivable to use LEDs.

[0019] The thermoswitch 7 is for cutting off the power supply to the coil 4 when the temperature of the coil 4 becomes a predetermined value or higher. In the present embodiment, it is assumed that the thermoswitch 7 is connected in series to the coil 4 and the first lighting unit 5.

[0020] Here, a plurality of types of failures related to the movable contact 3 can occur in the electromagnetic switch 1.

[0021] For example, when the switch operation is repeated in a short time, contact welding may occur where the movable contact 3 is welded to the pair of terminals 2 and does not separate.

[0022] Also, as the number of switch operations increases, powder generated during the connection and disconnection between the movable contact 3 and the pair of terminals 2 accumulates. In this case, contact clogging may occur where the accumulated powder hinders the movement of the movable contact 3.

[0023] Therefore, in the present embodiment, the combination of the lighting patterns of the first lighting unit 5 and the second lighting unit 6 is set to be different according to at least the types of failures that can occur in relation to the movable contact 3.

[0024] Hereinafter, referring to FIG. 2, the combination of the lighting patterns of the first lighting unit 5 and the second lighting unit 6 when a failure occurs in the electromagnetic switch 1 will be described.

[0025] (1) Normal state 1 (when the operation of the electromagnetic switch 1 is instructed)

[0026] First lighting unit 5: Since the operation of the electromagnetic switch 1 is instructed, the coil 4 is energized, and the first lighting unit 5 lights up.

[0027] Second lighting unit 6: When the coil 4 is energized, the movable contact 3 is connected between the pair of terminals 2, so the second terminal 2b is energized and the second lighting unit 6 lights up.

[0028] Based on the above, under normal conditions (when electromagnetic switch 1 is instructed to operate), the combination will be "First lighting unit 5: lit" and "Second lighting unit 6: lit".

[0029] (2) Normal operation 2 (when electromagnetic switch 1 is not activated)

[0030] First lighting unit 5: Since the operation of the electromagnetic switch 1 is not instructed, the coil 4 is not energized, and the first lighting unit 5 does not light up.

[0031] Second lighting unit 6: Since coil 4 is not energized, the movable contact 3 is not connected between the pair of terminals 2, and the second terminal 2b is not energized. Therefore, in this case, the second lighting unit 6 does not light up.

[0032] Based on the above, under normal conditions (when electromagnetic switch 1 is not instructed to operate), the combination will be "First lighting unit 5: Off" and "Second lighting unit 6: Off".

[0033] (3) Failure 1 (contact welding)

[0034] Contact welding is a phenomenon in which the movable contact 3 becomes welded to the pair of terminals 2 and cannot be separated. In this case, the electromagnetic switch 1 is activated even though it has not been instructed to be activated.

[0035] First lighting unit 5: Since the operation of the electromagnetic switch 1 is not instructed, the coil 4 is not energized, and the first lighting unit 5 does not light up.

[0036] Second lighting unit 6: Since the movable contact 3 is connected between the pair of terminals 2 by contact welding, the second terminal 2b is energized. Therefore, in this case, the second lighting unit 6 lights up.

[0037] Based on the above, it is shown that in the case of the combination of "first lighting unit 5: off" and "second lighting unit 6: on", "contact welding has occurred".

[0038] (4) Failure 2 (contacts are stiff)

[0039] Contact sticking is a phenomenon in which the movable contact 3 cannot be connected between a pair of terminals 2 due to the effects of accumulated powder, etc. In this case, the electromagnetic switch 1 is instructed to operate but does not operate.

[0040] First lighting unit 5: Since the operation of the electromagnetic switch 1 is instructed, the coil 4 is energized, and the first lighting unit 5 lights up.

[0041] Second lighting unit 6: Due to contact sticking, the movable contact 3 is not connected between the pair of terminals 2, so the second terminal 2b is not energized. Therefore, in this case, the second lighting unit 6 does not light up.

[0042] Based on the above, it is shown that in the case of the combination of "first lighting unit 5: lit" and "second lighting unit 6: off", "contact sticking has occurred".

[0043] (5) In case of malfunction 3 (when the thermoswitch is activated)

[0044] If the temperature of coil 4 exceeds a predetermined level, the thermoswitch 7 cuts off the power supply to coil 4. In this case, the electromagnetic switch 1 is instructed to operate, but does not operate.

[0045] First lighting unit 5: Since the power supply to coil 4 is cut off by the thermoswitch 7, the first lighting unit 5 is turned off.

[0046] Second lighting unit 6: Since coil 4 is not energized, the movable contact 3 is not connected between the pair of terminals 2, and the second terminal 2b is not energized. Therefore, in this case, the second lighting unit 6 does not light up.

[0047] Based on the above, the combination of "first lighting unit 5: off" and "second lighting unit 6: off" indicates that "thermoswitch 7 is operating."

[0048] Although this combination is the same as "Normal Operation 2," the user can distinguish between "Normal Operation 2" and "Fault Operation 3" based on whether or not the electromagnetic switch 1 is being activated.

[0049] Furthermore, if the temperature of coil 4 falls below a predetermined level, the interruption of power supply to coil 4 by the thermoswitch 7 is released, allowing the user to determine that "it will be possible to activate the electromagnetic switch 1 again after waiting for a while."

[0050] As described above, in the fault detection structure for the electromagnetic switch according to this embodiment, the combination of lighting patterns of the first lighting unit 5 and the second lighting unit 6 is set to differ according to at least the type of fault that may occur in relation to the movable contact 3.

[0051] With this configuration, if the user is informed in advance of the fault locations corresponding to the combination of lighting patterns of the first lighting unit 5 and the second lighting unit 6, the user will be able to easily determine "which part of the electromagnetic switch 1 is malfunctioning" when a malfunction actually occurs.

[0052] Furthermore, in the fault detection structure for the electromagnetic switch according to this embodiment, the case where the current to the coil 4 is cut off by the thermoswitch 7 is also included as a fault that may occur in relation to the movable contact 3.

[0053] With this configuration, if the user is made aware in advance of the combination of lighting patterns for the first lighting unit 5 and the second lighting unit 6 when the power supply to the coil 4 is cut off by the thermoswitch 7, the user can easily determine that "the thermoswitch 7 is operating" and that "it is possible to operate the electromagnetic switch 1 again after waiting for a while."

[0054] Furthermore, the fault detection structure for the electromagnetic switch of the present invention is not limited to the embodiments described above, and various modifications and improvements are possible within the scope described in the claims.

[0055] For example, in the above embodiment, the first lighting unit 5 was connected in series with the coil 4, and the second lighting unit 6 was connected between the second terminal 2b and GND. However, other connection patterns are also acceptable, as long as the combination of lighting patterns of the first lighting unit 5 and the second lighting unit 6 differs depending on the type of failure that may occur in relation to the movable contact 3. Naturally, patterns with the lighting and extinguishing reversed are also acceptable.

[0056] Furthermore, in the above embodiment, the determination of whether it is "normal operation 2" or "malfunction 3" was made based on whether or not the user instructed the operation of the electromagnetic switch 1. However, as shown in Figure 3, a third lighting unit 8 connected between the upstream side of the thermoswitch 7 and GND may also be provided.

[0057] In this case, as shown in Figure 4, "Normal state 2" is the combination of "First lighting unit 5: Off", "Second lighting unit 6: Off", and "Third lighting unit 8: Off", while "Fault state 3" is the combination of "First lighting unit 5: Off", "Second lighting unit 6: Off", and "Third lighting unit 8: On", making it possible to distinguish between the two.

[0058] Furthermore, in "Fault 3," if the temperature of coil 4 falls below a predetermined level, "Third lighting unit 8: Off," resulting in the same lighting pattern combination as in "Normal 2." Therefore, the user can determine that "they just need to wait until the third lighting unit 8 turns off."

[0059] Furthermore, in the above embodiment, the combination of lighting patterns of the first lighting unit 5 and the second lighting unit 6 was set to differ according to at least the type of failure that may occur in relation to the movable contact 3, but it may also be set to have different combinations that include other failures.

[0060] For example, in the configuration shown in Figure 3, it is possible to determine if a break has occurred in the power supply cord to coil 4. More specifically, if a break occurs in the power supply cord to coil 4, the lighting pattern will be the same as "Normal 2," but the user can determine whether it is "Normal 2" or "Break in the power supply cord to coil 4" based on whether or not the electromagnetic switch 1 has been activated.

[0061] Furthermore, it is possible that the coil 4 itself may break. In this case, using the configuration in Figure 1, the lighting patterns would be a combination of "Normal 2" and "Fault 3" in Figure 2. In this case, the user would assume that the thermoswitch 7 has activated and wait for a while. However, if the electromagnetic switch 1 cannot be activated even after waiting for a while, it becomes possible to determine that "the coil 4 itself has broken."

[0062] Furthermore, as shown in Figure 5, a fourth indicator light 9 may be provided, which is connected to the first terminal 2a and lights up depending on whether or not the first terminal 2a is energized. In this case, it becomes possible to determine whether or not the power supply itself has malfunctioned based on whether or not the fourth indicator light 9 is lit. [Explanation of Symbols]

[0063] 1. Electromagnetic switch 2 terminals 2a First terminal 2b Second terminal 3 Movable contacts 4 coils 5. First lighting section 6. Second lighting section 7 Thermoswitch 8. Third lighting section 9. Fourth lighting section

Claims

1. A pair of terminals having a first terminal located upstream in the direction of current flow and a second terminal located downstream, A movable contact that can be connected between the pair of terminals is provided to conduct current between the pair of terminals, A coil that generates a magnetic force such that the movable contact is connected to the pair of terminals when power is applied, A first lighting unit connected to the coil, which lights up depending on whether the coil is energized or not, A second lighting unit connected to the second terminal, which lights up depending on whether or not the second terminal is energized, Equipped with, The fault detection structure for an electromagnetic switch is characterized in that the combination of lighting patterns of the first lighting unit and the second lighting unit is set to differ according to at least the type of fault that may occur in relation to the movable contact.

2. The system further includes a thermoswitch for cutting off the power supply to the coil when the temperature of the coil exceeds a predetermined level. The first terminal and the coil are each supplied with power independently. The first lighting unit is connected in series with the coil, The second lighting unit is connected between the second terminal and GND, The thermoswitch is connected in series with the coil and the first lighting unit. The fault determination structure for an electromagnetic switch according to claim 1, characterized in that the case when the current to the coil is interrupted by the thermoswitch is also included in the faults that can occur in relation to the movable contact.

3. The system further comprises a third lighting unit connected between the upstream side of the thermoswitch and GND, The fault determination structure for an electromagnetic switch according to claim 2, characterized in that the combination of lighting patterns of the first lighting unit, the second lighting unit, and the third lighting unit is set to differ according to at least the type of fault that may occur in relation to the movable contact.

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