JPH0755022B2 - Abnormality detection device for contactless contactor - Google Patents

Description

The present invention relates to an SSC abnormality detection device, and more particularly to an SSC abnormality detection device when the SSC is used in a reversible operation system.

A three-phase contactless contactor (hereinafter, this contactless contactor is abbreviated as SSC) stores switching elements such as a plurality of thyristors and their respective control circuits in one case to open and close a three-phase electric circuit. It is used for This SSC is used for opening and closing various three-phase loads including three-phase motors because it has no electrical and mechanical wear parts and can withstand frequent opening and closing.
However, the switching elements inserted in each phase are opened and closed by the ignition circuit that has a zero-cross circuit, so if some of the firing circuits or switching elements fail, the load becomes unbalanced. In the case of a three-phase motor, an accident occurs in which the motor is burnt out by operating in a single phase.

[Conventional technology]

A conventional example of this type of SSC abnormality detection device is shown in FIG. Here, the three-phase motor 1 is connected to the power supply RST via SSC2. The abnormality detection unit 3 includes an operation input terminal 3a, an abnormal voltage detection terminal 3b, and an abnormality output terminal 3c. The operation input terminal 3a is connected in parallel with the ignition circuit 2a of the SSC2 connected to the control power source 5 via the operation switch 4. It is connected. Abnormal voltage detection terminal
3b is connected to the output terminal UVW of SSC2. The abnormality output terminal 3c is derived from a contact of a switching relay (not shown) included in the abnormality detection unit 3 and is connected to a trip coil of a circuit breaker connected to the power source RST or an alarm device.

When SSC2 is open, the line voltage at its output terminal UVW is zero.
When the operation switch 4 is closed here, SS is turned on via the ignition circuit 2a.
Since C2 is closed, a line voltage appears at its output terminal UVW. The abnormality detection unit 3 outputs an abnormal output to the abnormal output terminal 3c as a conduction failure of the SSC2 when the line voltage of the output terminal UVW of the SSC2 is detected at the abnormal voltage detection terminal 3b even though no operation input is applied to the input terminal 3a. Is sent. If no line voltage is detected at the abnormal voltage detection terminal 3b despite the operation input being applied, an abnormal output is sent to the abnormal output terminal 3c as an open failure of the SSC2. Then, the circuit breaker or the alarm device is operated by this output.

[Problems to be solved by the invention]

As described above, when operating one three-phase motor with one SSC, there is no problem with the above configuration. However, there are cases where two SSCs are used to reversibly operate a three-phase motor, so this point will be considered. FIG. 3 is a wiring diagram of a reversible operation system using two SSCs, showing an example in which a conventional abnormality detection unit is further connected. Here, the same parts as those in FIG. 2 are designated by the same reference numerals as those in FIG. did. In FIG. 3, the three-phase motor 1 is an SS for forward rotation.
It is connected to the three-phase AC power supply RST via C2. In addition, this three-phase motor 1 has a three-phase AC power supply RST via the SSC6 for reverse rotation.
It is connected to the. The phase rotation order of the power supply RST connected to the motor 1 is reversed in both SSCs 2 and 6. Both SSC
The reversible unit 7 which opens and closes 2,6 is a forward rotation operation switch 4a,
It is connected to the control power source 5 via the reverse rotation operation switch 4b. The abnormality detection unit 3 is connected as follows. That is, only the operation input of the switch 4a is connected to the input terminal 3a and the operation input of the switch 4a is applied, and the output terminal UVW of the SSC2 is connected to the abnormal voltage detection terminal 3b. Here, when the operation switch 4a is closed, the SSC2 becomes conductive and the motor 1 rotates in the forward direction. Further, when the switch 4a is opened and the switch 4b is closed, SSC2 becomes non-conductive while SSC6 becomes conductive and the motor 1 rotates in the opposite direction. Here, as is apparent from FIG. 3, when the reversible operation of the motor 1 is performed using SSC2 and SSC6, the phase rotation may be reversed, so that SS
SSC6's R and T phases are connected so that they are opposite to the C2 R and T phases, and SSC2 and SSC6 are connected in parallel for the S phase that does not need to change the phase. They are connected so that they are in phase.

By the way, when both switches 4a, 4b are open, both SSCs 2, 6
Is open, but if a line voltage appears at the output terminals UVW of both SSCs 2 and 6 at this time, the abnormality detection unit 3 detects that there is a conduction failure in either of the SSCs 2 and 6 because no operation input is applied. . Also, when switch 4a is closed, SSC2 is closed, but if a normal three-phase voltage does not appear at the output terminal of SSC2 at this time, the abnormality detection unit 3 has an operation input applied, so SSC2
Detected as an open failure. Next, when the switch 4a is opened and the switch 4b is closed, SSC6 is closed and a three-phase voltage appears at the output terminal UVW of SSC6 and the motor 1 should rotate in the reverse direction. However, at this time, since no operation input is applied to the abnormality detection unit 3, the abnormality detection unit 3 detects it as a conduction failure. That is, the abnormality detection unit 3 erroneously detects the reverse rotation operation of the reversible operation device as a conduction failure. The operation input of the operation switches 4a and 4b is applied to the input terminal 3a of the abnormality detection unit 3, or the abnormality detection unit is divided into forward rotation SSC and reverse rotation SSC and connected to the respective SSCs 2 and 6. It is possible that the S phases of SSC2, 6 are connected in parallel because they may be in the same phase, and when one of the SSCs is in the operating state, the other S phase is in a short-circuit state, so the S phase is in a conduction failure. The same phenomenon that is occurring appears,
Despite normal operation, it is erroneously detected as a conduction abnormality. That is, there is a problem that the SSC abnormality detection device having such a configuration cannot be used for a reversible operation device.

It is an object of the present invention to provide an anomaly detection device that can accurately detect an anomaly in a switching element of an SSC with a single anomaly detection unit even in a reversible operation device using two SSCs.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is a contactless contactor abnormality detection device for reversibly operating a three-phase motor by connecting two three-phase contactless contactors, and opening and closing the three-phase contactless contactor. Contactless contact having an abnormality detection unit that detects an operation input and an abnormal voltage at the output end of the contactless contactor, and detects an abnormality of the contactless contactor based on the operation input and the abnormal voltage. In the abnormality detection device for a vessel, the operation input of the abnormality detection unit is an auxiliary input applied from each auxiliary normally open contact of the two non-contact contactors, and among the two three-phase non-contact contactors. One of the features is that each of the phases is short-circuited.

[Action]

In the present invention thus configured, when the two SSCs are connected for reversible operation, if the forward rotation operation input and the reverse rotation operation input are not applied, the forward rotation SSC and the reverse rotation SSC are not applied.
Since these are also open, these auxiliary normally open contacts are also open, and no auxiliary input is applied to the abnormality detection unit. Therefore both SS
If a voltage is detected at the output of C, this is a conduction failure of either SSC. When an operation input is applied here and any one of the two SSCs is closed, the auxiliary input is applied to the operation input terminal of the abnormality detection unit via these auxiliary normally open contacts. If the voltage detection terminal does not detect the output voltage at the output terminal of the SSC, it is determined that the SSC has an open failure. That is, this configuration is characterized in that if either SSC is closed, both SSCs are simultaneously detected. In addition, if the switching element of one phase of the three-phase SSC is short-circuited, the one-phase conduction failure can be detected,
It is possible to prevent a phase-to-phase short circuit of the power supply that is expected at the time of forward / reverse switching.

〔Example〕

One embodiment of the present invention is shown in FIG. Here, Fig. 2 and 3
The same parts as those in the figure are designated by the same reference numerals as those in FIGS. 2 and 3. In FIG. 1, the three-phase motor 1 is connected to the three-phase power source RST via both SSCs 2 and 6 as in the conventional one, and both SSCs 2 and 6 are connected.
Therefore, the phase rotation order of the power supply RST connected to the motor 1 is reversed. Further, in both of these three-phase SSCs 2 and 6, the S phase is short-circuited and the switching element of this phase is omitted. For this reason, the connection of the S phase of SSC6 is omitted. The reversible unit 7 that opens and closes both SSCs 6 is connected to the control power source 5 through both switches 4a and 4b as in the conventional one, and the ignition circuits 2a and 6a of the respective SSCs 2 and 6 are connected by these switches 4a and 4b. Is connected to fire. The abnormality detection unit 3 is connected as follows. That is, the auxiliary normally open contacts 2b and 6b of both SSCs 2 and 6 are connected in parallel, this parallel circuit is connected to the operation input terminal via the control power source 5, and the abnormal voltage detection terminal 3b is connected to the output terminal UVW of SSC2. Has been done. Of course, the abnormal output terminal 3C is connected to a trip coil, an alarm device, etc. of the circuit breaker of the power supply RST (not shown).

With such a configuration, the motor 1 is operated in the reversible unit 7 in the same manner as the conventional one, and thus the description thereof is omitted and only the SSC abnormality detection operation will be described. First, when both SSCs 2 and 6 are open, no input is applied to the input terminal 3a of the abnormality detection unit 3, so if a voltage is applied to the abnormal voltage detection terminal at this time, the abnormality detection unit 3 will have a conduction failure in both SSCs 2 and 6. To detect. Next, for example, when the switch 4a is closed, SSC2 is closed and the motor 1 is normally rotated. At this time, the auxiliary normal point 2b of SSC2 is also closed, so the input terminal 3a of the abnormality detection unit 3 has this contact.
A 2b auxiliary input is applied. Therefore, at this time, if the abnormality detection unit 3 does not detect the voltage of the output terminal UVW of SSC2, it is regarded as an open failure of SSC2. Next, when switch 4a is opened and switch 4b is closed, SSC2 is opened, SSC6 is closed, and motor 1
Is reversed. At this time, since the auxiliary normally open contact of SSC6 is also closed, the auxiliary input from this contact 6b is applied to the input terminal 3a of the abnormality detection unit 3. Therefore, at this time, if the abnormality detection unit 3 does not detect the voltage at the output end of SSC6, SSC6
It is considered as an open failure. That is, when SSC2 is closed, SSC6
Even when is closed, since the auxiliary input is applied to the input terminal 3a of the abnormality detection unit 3, the operation of both SSCs 2 and 6 will not be erroneously detected.

However, this anomaly detection unit detects the anomaly by catching the line voltage at the output end of the SSC.Therefore, in the two-phase open and one-phase conduction of the SSC failure modes, no voltage appears between the lines, so the anomaly is detected. Can not do it. This does not cause the load to fail in the case of isolated operation, but in the case of reversible operation of two SSCs, a one-phase conduction failure in one SSC causes an interphase short circuit when the other SSC is closed. Therefore, if one phase switching element of at least one of the two SSCs is set as a short-circuited two-phase SSC, a line voltage occurs when the other one causes a conduction failure, and the abnormality detection unit detects this. Therefore, if the switching time of the reversible unit is set to be longer than the detection time of the abnormality detection unit and the power supply RST is cut off by the operation of the abnormality detection unit, it is possible to prevent the power supply phase short circuit during the reversible operation. The present invention can also be implemented by combining two or more SSCs having auxiliary normally open contacts.

〔The invention's effect〕

As described above, according to the present invention, there is provided a contactless contactor abnormality detecting device for reversibly operating a three-phase motor by connecting two three-phase contactless contactors. Contactless contact having an abnormality detection unit that detects an operation input and an abnormal voltage at the output end of the contactless contactor, and detects an abnormality of the contactless contactor based on the operation input and the abnormal voltage. In the abnormality detection device for a vessel, the operation input of the abnormality detection unit is an auxiliary input applied from each auxiliary normally open contact of the two non-contact contactors, and among the two three-phase non-contact contactors. By constructing a reversible operation system by combining two SSC units by short-circuiting each one phase, connect these auxiliary normally open contacts in parallel and
If SSCs are targeted for detection at the same time, it is possible to detect SSC abnormalities without erroneous detection using the same abnormality detection unit as in the past. Also, short one switching element of the three-phase SSC,
Since a two-phase SSC can also detect a one-phase conduction failure, it is also possible to prevent a short-circuit between phases of the power supply during forward / reverse switching during reversible operation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment in which the SSC abnormality detecting device according to the present invention is used in a reversible operation device of a three-phase motor, FIG. 2 is a block diagram of a conventional SSC abnormality detecting device, and FIG. The abnormality detection device shown in FIG.
It is a block diagram which shows an example used for SSC. 2,6: SSC, 3: Abnormality detection unit, 2a, 6a: Auxiliary normally open contact.

Claims (1)

[Claims] 1. An abnormality detecting device for a contactless contactor for reversibly operating a three-phase motor by connecting two three-phase contactless contactors, wherein an operation input for opening and closing the three-phase contactless contactor is provided. An abnormality detecting device for a non-contact contactor comprising an abnormality detecting unit for detecting an abnormal voltage at an output end of the non-contact contactor and detecting an abnormality of the non-contact contactor based on the operation input and the abnormal voltage. The operation input of the abnormality detection unit is an auxiliary input applied from the auxiliary normally open contact of each of the two contactless contactors, and one of the two three-phase contactless contactors is short-circuited. An abnormality detection device for a contactless contactor characterized in that