JP2544376B2 - Motor protection relay - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor protection relay of a collective type provided with an antiphase element, and more particularly to a workability of wiring work between a current or phase detector and a relay unit. The present invention relates to a configuration of a motor protection relay that is suitable for improving and miniaturizing a relay unit.

[Conventional technology]

Fig. 11 ~ Typical configuration example of conventional motor protection relay
It is shown in FIG. A current detector 120 consisting of a current transformer 2 provided in the protected circuit 1 and a circuit 3 for producing an output corresponding to a load current of each phase, and a current detector 120 connected to the current detector 120 by a connecting line 12 to set an operating value. The current settling circuit 6 determines the overcurrent circuit 7 or the open phase circuit 8 based on the normalized signal, and drives the output relay 9 when an abnormality occurs.

As a device related to this kind of device, for example, Japanese Utility Model Publication No. 59-132338 can be cited.

[Problems to be solved by the invention]

In the above-mentioned conventional technique, when the antiphase is protected to prevent the reverse rotation of the motor, in general, each phase voltage of the protected circuit 1 is taken in by the signal line 10, and the antiphase detection circuit 111 detects the presence or absence of the antiphase. If the number of connecting wires 12, 10 connecting the relay unit 112, the current detecting unit 120, and the protected circuit is large and the positions are distant from each other, the connecting man-hours between them are There was a problem that it would be enormous.

In particular, as shown in FIG. 12, when there are many protected circuits 1 and the relay units 112 corresponding to each are grouped, the number increases according to the number of circuits, and in the example of FIG. On the other hand, it is necessary to wire 15 connecting wires, which requires a lot of wiring man-hours for the user.
Along with that, there is a problem that reliability is also lowered.
An object of the present invention is to reduce the number of wirings of the connecting wires and to obtain a configuration that can easily cope with the improvement in function.

[Means for solving problems]

The above object is to detect a load current, a first signal generating circuit for generating a signal based on the output of the current detecting means, a phase detecting means for detecting a phase of a load voltage, and the phase detecting circuit. Second for generating a signal based on the output of the means
Signal generating circuit, an overcurrent detecting circuit that detects an overcurrent from the signal of the first signal generating circuit to generate an output, and an antiphase signal from the signal of the second signal generating circuit to detect an output and output A reverse phase detection circuit that is generated, and a relay that operates based on the output of at least one of the overcurrent detection circuit and the reverse phase detection circuit. The signal of the generating circuit and the second
A superimposing means for superimposing a signal of the signal generating circuit on the other side, and a distributing means for distributing the output of the superimposing means to the overcurrent detecting circuit and the anti-phase detecting circuit, and the second signal generating circuit on the second side. The first signal generating circuit and the second signal generating circuit are arranged in the vicinity of the first signal generating circuit and are connected between the superposing means and the distributing means through a connection line. This is achieved by arranging the output to be transmitted to at least one of the overcurrent detection circuit and the antiphase detection circuit.

According to a preferred embodiment, a first case for storing the current detecting means, the first signal generating circuit and the superposing means, and a second case for storing the phase means and the second signal generating circuit. And the second case is fixed to the first case.

According to a further preferred embodiment, the second case is detachably fixed to the first case.

[Action]

The first signal generating circuit generates a signal based on the output of the current detecting means. The second signal generating circuit is arranged in the vicinity of the first signal generating circuit and generates a signal based on the output of the phase detecting means. The superimposing means superimposes the output of the second signal generating circuit on the output of the first signal generating circuit and transmits the output of the second signal generating circuit to the distributing means via the connection line, and the distributing means distributes the output of the superimposing means to the overcurrent detection circuit and the negative phase. Distribute to the detection circuit. The overcurrent detection circuit detects an overcurrent from the signal of the first signal generation circuit to generate an output, and the antiphase detection circuit detects an inversion of the phase sequence from the signal of the second signal generation circuit to generate an output. To do. The relay operates based on the output of at least one of the overcurrent detection circuit and the anti-phase detection circuit to generate an output corresponding to an abnormality in current or voltage. Thereby, the output of the first signal generating circuit and the output of the second signal generating circuit are superimposed and transmitted to the distributing means through the common connecting line, so that the connecting line between the superimposing means and the distributing means. The number of can be reduced.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing the configuration of the motor protection relay in this embodiment. A current transformer 2 is provided as a current detecting means in the electric circuit 1 of the protected circuit, and each current transformer 2 is delta-connected and connected to a rectifier circuit 3 which is a first signal generating circuit. The rectifier circuit 3 is a bridge circuit formed by the diodes D _{31 to} D ₃₆ , and converts the output of the current transformer 2 into a DC signal based on the magnitude of the current in the electric line 1. An example of the output of the rectifier circuit 3 in this embodiment is shown in FIGS. 4 (a) and 4 (b).
FIG. 4 (a) shows the output waveform when the current value is 100% of the rated value and under normal energization, and FIG. 4 (b) is the output waveform when the current value is 200% of the rated value and overloaded. The peak value of the output is 1V when the current is 100% of the rated value, and this peak value rises as the load current increases, and the peak value becomes 2V when the rated current is 200%. The level of the peak value of the output voltage determines whether the overcurrent is occurring. Further, the phase loss can be detected by checking the ripple content of the output of the rectifier circuit 3. The output waveform when the open phase occurs at the rated current is shown in FIG. The output of the rectifier circuit 3 is supplied to the tap settling circuit 5 via a superimposing circuit 4 which is a superimposing means. As shown in FIG. 2, the superimposing circuit 4 in this embodiment has a signal input terminal T ₄₁ from the rectifying circuit 3 and a signal input terminal from the phase signal generating circuit 16 which is the second signal generating circuit.
And T ₄₂ , and the input terminal T ₄₂ is connected to the input terminal T ₄₁ via a diode D ₄₁ . The tap settling circuit in this embodiment is composed of three resistors R ₅₁ , R ₅₂ , R ₅₃ and a settling value changeover switch sw1. Resistor R ₅₁ is connected between the common line terminals T ₅₂ and the output terminal T ₅₁ of the superposition circuit 4, the resistors R _52, R ₅₃ also settling Any value switching switch sw1
Is connected in parallel to the resistor R ₅₁ via.

The changeover switch sw1 has three sets of contacts S provided facing each other.
₁ , S ₂ and S ₃ are provided, and one set among them is selectively selected. As an example of a specific configuration, the pattern of the printed circuit board is configured to be short-circuited with a screw,
S _1, S _2, the resistance value of R ₅₁ by shorting alternatively one of S _3, parallel value of R ₅₁ and R _52, is changed from parallel value of R ₅₁ and R ₅₃ Then, the voltage generated between the output terminals T ₅₃ and T ₅₄ is changed.

In this embodiment, the AC device 2, the rectifier circuit 3, the superposition circuit 4,
The tap settling circuit 5 is housed in the same case and constitutes the current detection unit 20.

FIG. 3 shows an example of a concrete circuit of the phase detection circuit 13 which is the phase detection means and the phase signal generation circuit 16 which is the second signal generation circuit. In this embodiment, the phase detection circuit 13 and the phase signal generation circuit 16 are housed in the same case, and constitute the phase detection unit 30. In Fig. 3, R ₁₃₁
~ R ₁₃₄ , R ₁₆₁ ~ R ₁₆₆ are resistors, D ₁₃₁ , D ₁₆₁ , D ₁₆₂ are diodes, C ₁₃₁ , C ₁₃₂ , R ₁₆₁ ~ R ₁₆₅ are capacitors, ZD ₁₆₁ is a zener diode, Q ₁₆₁ is a transistor . The terminals T ₃₁ , T ₃₂ , and T ₃₃ of the phase detection unit 30 are respectively w of the electric circuit 1.
It is connected to the phase, v phase, u phase, and takes in the voltage of the electric path.

The phase detection circuit 13 detects the voltage of each phase, and the phase signal generation circuit 16 is based on the output of the phase detection circuit 13 and when the phase order is not normal, that is, in the reverse phase, it is larger than the overcurrent or open phase signal. It is configured to output a level signal.

In a normal phase sequence, a predetermined voltage is generated between both ends AB of the resistor R ₁₃₃ , and the voltage between AB becomes small at the reverse phase (reverse phase).

As a result, in the phase signal generating circuit 16, the transistor Q ₁₆₁ is turned on in the normal phase sequence and no voltage is generated between the output terminals T ₃₄ and T ₃₅ , but in the reverse phase, the transistor Q ₁₆₁ is OF.
After that, an output is generated between the output terminals T ₃₄ and T ₃₅ . This output level is set to about 15 times the output of the rectifier circuit 3, and it is possible to judge whether it is an overcurrent or a reverse phase by this level difference. An example of the output of the phase signal generation circuit 16 is shown in FIG.

5 and 6 show configuration examples of the current detection unit 20 and the phase detection unit 30 in this embodiment. In this embodiment, the phase detection unit 30 is detachably locked to the current detection unit 20. The surface of the phase detection unit 30 facing the current detection unit 20 is provided with a connector 14 for connecting the output of the phase signal generation circuit 16 to the superposition circuit 4 and the terminal T _{55 of the} common line. It is configured so that it can be electrically connected to the 20 at the same time.

As a result, the output of the phase signal generation circuit 16 is the rectification circuit 3
And is transmitted to the relay unit 40 via the cable 12 for transmission. The relay unit 40 includes a current setting circuit 6, an overcurrent detection circuit 7, an open phase detection circuit 8, an antiphase detection circuit 15, an OR circuit 42, an amplification circuit 46, and a relay 9. The relay unit 40 is a current setting unit. Depending on the level of the signal received by the circuit 6, it is determined whether there is an overcurrent or an antiphase, and after each delay time, by driving the output relay, for the two accident modes,
Protect.

Further, in the present embodiment, it is possible to discriminate a loss accident based on the ripple content rate and drive the motor soundly.

Next, each component will be described. The current settling circuit 6
After setting the signal received through the cable 12 to a current of an appropriate magnitude, the signal is distributed to the overcurrent detection circuit 7, the open-phase detection circuit 8 and the anti-phase detection circuit 15 to function as distribution means.

The overcurrent detection circuit 7 determines whether or not the current is larger than the reference value and generates a signal when the overcurrent occurs, and the open phase detection circuit 8
Determines whether there is an extreme difference in the current of each phase and generates a signal when there is a phase loss.

The open-phase detection is a voltage signal, and the over-current accident time open-phase detection is determined by an increase in the ripple (high frequency component) included in the voltage signal during the open-phase accident.

The anti-phase detection circuit 15 detects the level of the voltage signal transmitted via the cable 12, and when this level is very large with respect to the signal for the overcurrent or the signal for the open phase, the anti-phase is detected and the output is output. appear. The criteria for judging a rebellion are:
As an example, it is set to about 10 to 15 times the voltage signal at the rated current. The OR circuit 42 generates an output when at least one of the overcurrent detection circuit 7, the open phase detection circuit 8, and the antiphase detection circuit 15 operates and a signal is input. The amplifying circuit 46 amplifies the output of the OR circuit 42 so that the output is large enough to operate the relay 9.

In this embodiment, as shown in FIG. 7, the relay unit 40 is integrally put in a case as a module to support centralized monitoring. In such a centralized relay, since the number of connection terminals with the detector can be reduced as shown in this embodiment, the products can be compactly assembled as shown in FIG. Although FIG. 8 shows a circuit for 5 circuits, 5 circuits of 5 terminals, 3 terminals 17 of 1a, 1b and common as each unit output contact, and 2 terminals 18 used for connection to the detector are provided. At 25
A total of 27 terminals including the terminals and 2 terminals for the power supply are required, which allows the product to be made compact.

It should be noted that FIG. 8 shows an example in which terminals greater than the above number of terminals are provided so that the relay unit 40 may be added.

FIG. 9 shows an example of a circuit diagram of the integrated structure as shown in FIG.

In the present embodiment, the current detection unit 20 is made by combining the current transformer 2 and the electric circuit portion into one body and is used for overcurrent protection or open phase protection (2E relay). Two elements are sufficient for a general motor relay, and many of the devices on the market take this form.

In the present embodiment, in consideration of the above situation, the portion 30 relating to the antiphase detection is made independent and detachable. When a 3E relay (overcurrent, open-phase, anti-phase protection) is required, it can be easily expanded to 3E by adding the module 30.

That is, general 2E operation is performed by using only the current detection unit 20, and in the case of 3E operation including antiphase, the phase detection unit 30 is additionally used.

In either case, the number of connecting wires 5 to the relay unit 40 is only two, and there is an effect that mutual wiring can be simplified.

In addition, there is an effect that it can immediately respond to the specification change from 2E to 3E.

Further, the current detection unit 20 and the phase detection unit 30 may be integrally formed, and in any case, the total man-hours for disposing can be effectively reduced.

Further, in this embodiment, the outputs from the current detection unit 20 and the phase detection unit 30 are transmitted by analog signals, and although two or more cables 12 are necessarily required for transmission, the reliability is very high. Is the most primitive for a relay that is extremely expensive and does not allow malfunctions,
It is a reliable method.

Further, in the motor protection relay, the phase sequence is mainly detected to determine whether or not the motor rotates in a desired rotation direction, and this function is important for safety.

In this embodiment, overcurrent, separation of the open phase signal and the reverse phase signal is basically performed by the difference in voltage level.
As shown in the figure, the antiphase is instantly determined at the stage when the voltage is applied. At this stage, after it is determined that the phase is positive, the open phase and the overcurrent are determined. Thus, with respect to the operation of the motor, those having a high degree of risk are detected, so that the motor can be effectively protected.

〔The invention's effect〕

According to the present invention, the number of connecting wires can be reduced, workability can be significantly improved, the number of connecting terminals can be reduced, and a motor protection relay that can achieve a compact product can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a motor protection relay in one embodiment of the present invention, FIG. 2 is a circuit diagram showing a main part of a current detection unit in this embodiment, and FIG. 3 is a phase in this embodiment. Circuit diagram of the detection unit, FIG. 4 (a),
(B), (c), (d) are the current detection units, respectively.
Waveform showing output waveform at 100% rated energization, output waveform at 200% overload of current detection unit, output waveform at 100% rating of current detection unit at open phase, output waveform of phase detection unit at antiphase Figure, Figure 5,
FIG. 6 is a perspective view showing a coupled state and a detached state of the current detection unit and the phase detection unit in this embodiment, respectively, and FIG. 7 is a perspective view of a collective relay formed by assembling the relay units in this embodiment. 8 is a perspective view showing the rear surface of the collective relay shown in FIG. 7, FIG. 9 is a circuit diagram showing an example of the circuit of the collective relay, FIG. 10 is a diagram showing the order of determining the abnormality of the electric circuit, and FIG. The figure is a block diagram showing the configuration of a conventional motor protection relay, and FIG. 12 is a wiring diagram showing the number of wirings of the conventional motor protection relay. 2: current detection means, 3: first signal generation circuit, 4: superposition means,
6: distribution means, 7: overcurrent detection circuit, 9: relay, 12: connection line, 13: phase detection means, 15: antiphase detection circuit, 16: second signal generation circuit.

Claims (3)

(57) [Claims] 1. A current detecting means for detecting a load current, a first signal generating circuit for generating a signal based on an output of the current detecting means, and a phase detecting means for detecting a phase of a load voltage.
A second signal generating circuit for generating a signal based on the output of the phase detecting means; an overcurrent detecting circuit for detecting an overcurrent from the signal of the first signal generating circuit to generate an output; A reverse phase detection circuit that detects a reverse phase from the signal of the signal generation circuit and generates an output, and a relay that operates based on the output of at least one of the overcurrent detection circuit and the reverse phase detection circuit. A motor protection relay comprising: a superimposing means for superimposing a signal of the first signal generating circuit and a signal of the second signal generating circuit; and an output of the superimposing means for the overcurrent detection circuit and Distribution means for distributing to the anti-phase detection circuit, the second signal generation circuit is arranged in the vicinity of the first signal generation circuit, and is connected between the superposition means and the distribution means. Via the connecting line Motor protective relay, characterized in that it is configured to transfer to either the output of the output and the second signal generation circuit of No. generating circuit at a minimum of the overcurrent detection circuit and the anti-phase detecting circuit. 2. A first case for storing the current detecting means, the first signal generating circuit and the superposing means, and a second case for storing the phase detecting means and the second signal generating circuit.
The case according to claim 1, wherein the second case is fixed to the first case.
Motor protection relay described in paragraph. 3. The motor protection relay according to claim 2, wherein the second case is detachably fixed to the first case.