JPH0763206B2 - Abnormality detection device for contactless contactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention detects an abnormality in a three-phase contactless contactor (hereinafter, this contactless contactor is abbreviated as SSC) using a thyristor as a switching element. Regarding a detection device.

[Conventional technology]

SSC consists of multiple thyristors and their respective control circuits
It is used to open and close the three-phase electric circuit in a case. Since this SSC has no electro-mechanical wear parts and can withstand frequent switching, it is used to switch various three-phase loads including three-phase motors, but the thyristors inserted in each phase each have a zero-cross circuit. Since it is closed by an arc circuit, if some of the ignition circuits or thyristors may fail, the load will become unbalanced, and in the case of a three-phase motor, an accident such as single-phase operation and burnout will occur. . Therefore, conventionally, a method has been adopted in which an abnormality detection device as shown in FIG. Here, the three-phase motor 1 is connected to the power supply RST phase via SSC2. The abnormality detection device 3 includes an operation input detection circuit 4, a rectifier circuit 6, a smoothing circuit 7, a delay circuit 8, and a relay circuit 9,
The operation input detection circuit 4 has an auxiliary relay 5 and an operation switch.
It is connected in parallel with the ignition circuit 2a of SSC2 connected to the power supply RS phase via 10. A three-phase full-wave rectifier circuit 6 is connected to the UVW phase on the output side of the SSC, and the DC output voltage of this rectifier circuit 6 is smoothed by the smoothing circuit 7 via the normally closed contact 5a of the output relay 5, and the delay circuit 8 It is delayed by and input to the relay circuit 9. The relay circuit 9 is an output relay 11 having a switching contact 11a.
Equipped with a contact 11a of this output relay 11 such as SSC2
It is connected in series with the trip coil of a wiring breaker (not shown) connected to the power supply side of this SSC2, and when the SSC2 is abnormal, the trip coil is configured to shut off the wiring breaker. Of course, the contact device 11a can also operate the notification device by light or sound.

When the switch 10 is closed when the SSC2 is healthy, the ignition circuit 2a operates by this operation input, the SSC2 is closed, and the motor 1 is started. At this time, since the operation input is also applied to the operation input detection circuit 4, the output relay 5 of the detection circuit 4 operates and the normally closed contact
5a is opened, the abnormality detection device 3 does not operate, and the output relay 11 does not operate.

Of course, if the operation switch 10 is open, the SSC2 will not close, so no voltage should be applied to the motor 1. However, if the SSC2 thyristor is damaged or the ignition circuit
When the thyristor becomes conductive due to the failure of 2a, the motor 1 starts even if the operation switch 10 is not closed if the thyristors of the respective phases are made conductive at the same time, and the motor 1 does not start but is burned if the thyristors of the two phases become conductive. In any case, it is dangerous. However, at this time, output relay 5
Is not operating, the contact 5a is closed. Therefore, the voltage appearing on the load side UVW phase is rectified by the rectifier circuit 6, smoothed by the smoothing circuit 7, and confirmed by the delay circuit 8 whether or not the SSC2 is abnormal. If the SSC2 is abnormal, the output circuit 9 Then, the output relay 11 is operated to trip the circuit breaker for wiring, for example.

[Problems to be solved by the invention]

In this abnormality detection device, when the operation switch 10 is closed,
The input detection circuit 4 operates, and the output relay 5 operates to make contact 5a.
Is open, so if the firing circuit 2a fails or the thyristor is damaged and becomes non-conducting, for example, if no voltage is applied to the load side W phase, the motor 1 will not start by applying a single phase voltage and will burn out. There is a risk of In other words, this SSC abnormality detection device has a drawback that only a short-circuit abnormality of the thyristor can be detected, and an injection impossible abnormality cannot be detected. Also SSC 3
When one of the thyristors has a conduction failure, no line voltage is generated on the output side of the SSC, so this abnormality detecting device does not operate. That is, it is impossible to detect the one-phase conduction failure, which is the most frequent failure of the three-phase SSC, and there is a risk of causing an inter-phase short circuit when a two-phase SSC is used to reversibly operate a three-phase motor or the like. When you do the same reversible operation again,
With this anomaly detector, you should be able to open one
Although the operation input is not applied to the abnormality detection device attached to the SSC, the phase voltage of the other SSC appears at the output terminal of this SSC, so this abnormality detection device
It will be mistakenly detected as a continuity failure and the abnormality will be detected. Therefore, there is a problem that this abnormality detection device cannot be used for the reversible operation device of SSC.

An object of the present invention is to provide an SSC abnormality detection device that can detect an abnormality in even one three-phase SSC thyristor and can also be used as an SSC of a reversible operation device.

[Means for solving problems]

In order to solve the above problems, the present invention provides an abnormality detection device for a non-contact contactor that detects an abnormality of a non-contact contactor that includes a switching element for each phase and that opens and closes a three-phase electric circuit,
An operation input detection circuit that detects an operation input of the contactless contactor and issues an operation signal, an inter-electrode voltage detection circuit that detects an inter-electrode voltage of each of the switching elements and issues an inter-electrode voltage signal, and the operation signal ， A switch that emits an operating signal based on the voltage signal between contacts and does not detect the voltage signal between contacts of one phase of another contactless contactor for reversible operation of the motor as a load An abnormality detection logic circuit having a circuit, a delay circuit for delaying an operation signal from the abnormality detection logic circuit for a predetermined time, and a relay circuit operated by the operation signal from the delay circuit are provided.

[Action]

With the above configuration, when the abnormality detection logic circuit determines that there is a failure in the SSC based on the operation signal and the voltage signal between contacts, the operation signal is issued and confirmed by the delay circuit, and the alarm circuit is operated by the relay circuit or the power supply side It operates such as shutting off the circuit breaker. Furthermore, when two SSCs are connected as a reversible operation device, the abnormality detection logic circuit is equipped with a switch circuit that does not detect the voltage between contacts of the phase connected to one phase of other contactless contactor. Close to prevent false detection during reversible operation. In addition, a power supply voltage determination circuit is provided to determine whether or not a three-phase voltage is applied to the power source side of the SSC, and when it is not, the operation signal is stopped to prevent the SSC from erroneously detecting. Such an abnormality detection device is easy to handle if it is integrated into the SSC.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the SSC abnormality detecting device according to the present invention. The same parts as those in FIG. 6 are designated by the same reference numerals as those in FIG. In FIG. 1, the motor 1 is connected to a power source RST through a series circuit of SSC2 and circuit breaker 12. The abnormality detection device 3 includes an operation input detection circuit 4, a power supply voltage determination circuit 50, an inter-electrode voltage detection circuit 60, an abnormality detection logic circuit 70,
The operation input detection circuit 4 is provided with the delay circuit 8 and the relay circuit 9.
Is a circuit that detects the operation input of SSC2 and is connected in parallel with the firing circuit 2a of SSC2 that is connected to the power supply RS phase via the operation switch 10 and divides the voltage of the power supply RS phase as shown in FIG. resistance
The voltage is divided by 41 and 42, and this divided voltage is applied to the light emitting diode 43a of the photocoupler. Power supply voltage discrimination circuit 50 is SSC
It determines whether or not the power supply voltage is applied to 2. As shown in Fig. 3, the input terminal of the three-phase full-wave rectifier circuit 51 is connected to the RST phase on the power supply side of SSC2, and the DC output of the rectifier circuit 51. The ends are divided by voltage dividing resistors 52 and 53, and the divided voltage is connected to the light emitting diode 54a of the photocoupler. The inter-electrode voltage detection circuit 60 detects the inter-electrode voltage of each SSC thyristor. As shown in Fig. 4, the resistors 61, 62, 63 are connected to the respective light emitting diodes 64a, 65a, 66a of the respective photocouplers and the polarities thereof. Two sets of two zener diodes 67, 68, 69 connected in reverse to each other are connected in series, and three sets of circuits are connected one by one between the thyristors 2b, 2c, 2d of the SSC2. . As shown in FIG. 5, the abnormality detection logic circuit 70 includes a phototransistor 43b for the light emitting diode 43a of the operation input detection circuit 40 and phototransistors 64b, 65b for the light emitting diodes 64a, 65a, 66a of the inter-electrode voltage detection circuit 60. 66b and resistors 71 and 7 respectively
Smoothing circuits 75,7 consisting of 2,73,74 and resistors and capacitors
It is connected to 6,77,78 to form four sets of series circuits.
Each smoothing circuit 75,76,77,78 is a light emitting diode 43a, 61a, 6
Since 2a and 63a are driven by alternating current, the pulsation of the signal on the phototransistor side is removed, and the resistors 71, 72, 73, and 74 remove noise that enters each photocoupler. In addition to this circuit, a switch circuit in which a switch 80 and a resistor 79 are connected in series is provided, and the switch 80 is closed when two SSCs are used for a reversible operation device. These five sets of series circuits are connected to the control power supply VCC. Resistor 72, smoothing circuit
The connection point of 76 (this point is called B point) and the connection point of the resistor 74 and the smoothing circuit 78 (this point is called D point) are resistance.
It is connected to each input terminal of the NAND circuit 86 via 81 and 82. Further, the connection point of the resistor 73 and the smoothing circuit 77 (this point is referred to as C point) and the connection point of the switch 80 and the resistor 79 (this point is referred to as E point) are connected to the OR circuit 87 via resistors 83 and 84, respectively. The output terminal of the OR circuit 87 connected to each input terminal is connected to the other input terminal of the NAND circuit 86. The output terminal of the NAND circuit 86 is connected to one input terminal of the AND circuit 89, and the other input terminal of the AND circuit 89 is connected to the connection point of the resistor 71 and the smoothing circuit 75 via the series circuit of the resistor 85 and the inverter 88. (This point is called point A) is connected. Further, two input terminals of the NAND circuit 86 and one input terminal of the OR circuit 87 are connected to respective input terminals of the OR circuit 90, and an output terminal of the OR circuit 90 is connected to one input terminal of the AND circuit 91. The other input terminal of the AND circuit 91 is connected to the connection point of the resistor 85 and the inverter 88. The output terminal of the AND circuit 91 and the output terminal of the AND circuit 89 are connected to the respective input terminals of the OR circuit 92, and the output terminal of the OR circuit 92 is connected via the resistor 93 to the output terminal of the abnormality detection logic circuit 70. Is connected to the next delay circuit 8.
The collector and the emitter of the transistor 94 are connected between the output terminal of the abnormality detection logic circuit 70 and the negative side of the power supply VCC, and the power supply VCC is connected to the base through the resistor 95. The phototransistor 5 for the light emitting diode 54a of the discrimination circuit 50 is connected to the negative side of the
4b is connected.

Next, the operation of this abnormality detection circuit will be described. First, when SSC2 is normal, when switch 10 is closed, SSC2 is closed, so the voltage across SSC2 becomes almost 0, and each phototransistor 61b, 62b, 63b
Is in a non-conducting state. However, since the operation input is applied to the light emitting diode 43a, the phototransistor 43b is closed. Therefore, if point A in FIG. 5 becomes high level (hereinafter this high level is H), points B, C and D become low level (hereinafter this low level is L), and switch 80 is open. Since the point E is also L, the output of the OR circuit 87 is L and the output of the NAND circuit 86 is H. The output of the inverter 88 becomes L and the output of the AND circuit 89 becomes L. Also OR circuit 90
Is L, and the output of the AND circuit 91 is L. Therefore, the output of the OR circuit 92 is L, and the transistor 94
Whether the relay circuit 9 is turned on or off, the relay circuit 9 does not operate and the circuit breaker 12 is not shut off. Next, when the switch 10 is opened, the SSC2 is opened, but at this time, the thyristors 2b, 2c, 2d are connected to the snubber circuit (not shown), so that the motor 1
Since a voltage appears between the poles of each thyristor 2b, 2c, 2d, points B, C, D become H. At this time, since no operation input is applied, point A is L and switch 80 is open. E
The point is also L. Therefore, the output of the OR circuit 87 is H, the output of the NAND circuit 86 is L, the output of the AND circuit 89 is L, the output of the OR circuit 90 is H, the output of the AND circuit 91 is L, and the output of the OR circuit 92. Is L. Therefore, regardless of whether the transistor 94 is on or off, the relay circuit 9 does not operate and the circuit breaker does not break.

Next, the case where SSC2 is abnormal is described. If, for example, the R-phase thyristor 2b has an open failure when the switch 10 is closed and the SSC 2 is closed, the A and B points are both H, the C and D points are both L, and the switch 80 is open. The E point is also L. Therefore, since the output of the OR circuit 87 is L, the output of the NAND circuit 86 is H, and the output of the inverter 88 is L, the output of the AND circuit 89 is L. Further, the output of the OR circuit 90 becomes H and the output of the AND circuit 91 becomes H, so that the output of the OR circuit 92 becomes H. When the S-phase and T-phase thyristors 2b and 2d individually have an open circuit failure, or when two or more phases simultaneously have an open circuit failure, the output of the OR circuit 92 also becomes H. At this time, if the circuit breaker 12 is closed and the power supply voltage is sound, the phototransistor 54b for the light emitting diode 54a is closed, so the transistor 94 is in the OFF state, and the output H of the OR circuit 92 causes the delay circuit 8 to pass through the relay circuit. 9 is operated and the circuit breaker 12 is cut off. If the R phase is conducting when the switch 10 is opened and SSC2 is opened, both A and B points become L and C and D points become H. And when the switch 80 is opened, the E point becomes L. Then, according to the above-mentioned procedure, the output of the OR circuit 92 becomes H, and when the S phase and the T phase each have a conduction failure independently, or when the two or more phases have a conduction failure at the same time, the OR circuit 92 similarly outputs. The output of circuit 92 goes high. Of course, at this time, if the circuit breaker 12 is closed and the power supply RST is healthy and connected to SSC2, the phototransistor 54b is closed, so the transistor 9
4 is in the off state, the output H of the OR circuit 92 is the delay circuit 8,
The circuit breaker 12 is cut off via the relay circuit 9.

When two SSCs are used to perform reversible operation of a motor or the like, two SSCs, for example, S phases are connected in parallel, so that the S-phase thyristors 2c that are operated in parallel are always in a conducting state during the reversible operation. Therefore, there is a possibility that the abnormality detection device connected to the SSC on the open side may determine this thyristor 2c as a conduction failure and detect the abnormality. Therefore, as shown in FIG. 5, a switch circuit comprising a switch 80 and a resistor 79 for reversible operation is provided. That is, when the switch 80 is closed, the point E is always H, so that the output of the OR circuit 87 is always H and the output of the OR circuit 92 is not H even if the S-phase thyristor is closed and the point C is L. That is, when a reversible operation device is formed by using two SSCs, the switch 80 can be closed so that the thyristors connected in parallel are not detected as a conduction failure and the circuit breaker 12 is not cut off.

〔The invention's effect〕

As described above, according to the present invention, the normality and abnormality of SSC are determined based on the operation signal of SSC and the voltage signal between contacts, so that the open failure when SSC should be closed, SSC The conduction failure when the power should be open can be detected regardless of the number of phases of the failure. Also 2 SSCs
When a reversible operation of a motor or the like is performed by using a switch circuit provided so as not to detect a parallel phase as a conduction failure, the reversible operation can be dealt with without erroneous detection, the application range is widened, and the effect is great.

[Brief description of drawings]

1 to 5 respectively show an embodiment of an SSC abnormality detection device according to the present invention. FIG. 1 is a block diagram showing the abnormality detection device, FIG. 2 is a connection diagram of an operation input detection circuit, and FIG. Fig. 4 is a connection diagram of the power supply voltage discrimination circuit, Fig. 4 is a connection diagram of the inter-electrode voltage detection circuit, Fig. 5 is a connection diagram of the abnormality detection logic circuit,
FIG. 6 is a block diagram showing an example of a conventional SSC abnormality detection circuit. 2: SSC, 4: Operation input detection circuit, 8: Delay circuit, 9: Relay circuit, 50: Power supply voltage determination circuit, 60: Inter-electrode voltage detection circuit, 70:
Anomaly detection logic circuit.

Claims (2)

[Claims] 1. A contactless contactor abnormality detecting device for detecting an abnormality of a contactless contactor for opening and closing a three-phase electric circuit, comprising a switching element for each phase, and detecting an operation input of the contactless contactor. An operation input detection circuit that issues an operation signal, an inter-electrode voltage detection circuit that detects the inter-electrode voltage of each of the switching elements and issues an inter-electrode voltage signal, and an operation signal that is issued based on the operation signal and the inter-electrode voltage signal. Along with this, an abnormality detection logic circuit having a switch circuit for preventing the detection of the inter-electrode voltage signal of the phase connected to one phase of another non-contact contactor for reversible operation of the motor as a load, and this abnormality detection An abnormality detecting device for a contactless contactor, comprising: a delay circuit that delays an operation signal from a logic circuit for a predetermined time; and a relay circuit that operates according to the operation signal from the delay circuit. 2. The abnormality detection device for a non-contact contactor according to claim 1, wherein the non-contact contactor determines whether or not a power supply voltage is applied to the contactless contactor to issue a power supply voltage signal. Circuit, the abnormality detection logic circuit is an operation signal,
An abnormality detection device for a contactless contactor, which emits an operation signal based on a voltage signal between contacts and a power supply voltage signal.