JPH05315923A - Contactless switch circuit device - Google Patents

Abstract

PURPOSE:To allow the closing time of respective contactless switches to coincide with each other in a contactless switch circuit device consisting of plural contactless switches. CONSTITUTION:The contactless switch circuit device 10 consists of three contactless switches 1 (1A to 1C) each of which is provided with an input circuit 11 for judging the voltage level of an input voltage and outputting a control signal, a main circuit 13 having a bidirectional semiconductor switching element, e.g. a triode AC switch TRC, an ignition circuit 12 for outputting an ignition signal to the circuit 13 based upon the control signal outputted from the circuit 11, and a control signal terminal 14 for extracting the control signal outputted from the circuit 11 to the external and respective control signal terminals 14 are connected in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a bidirectional semiconductor switching element such as a triac and comprises a plurality of contactless switches for controlling the opening and closing of the main power supply line by turning on and off the semiconductor switching element. The present invention relates to a contactless switch circuit device.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram when a load such as a three-phase induction motor is driven using a conventional contactless switch circuit device. In FIG. 2, the contactless switch circuit device 10 has three
Each of the three contactless switches 1 (1A, 1B, 1C) is composed of three contactless switches 1 (1A, 1B, 1C) of U, V, W of the three-phase main power supply 3 and, for example, 3 The load 2 composed of a phase induction motor is connected in series with each phase and drives the load 2.

Each contactless switch 1 (1A, 1B, 1C)
Is an operating power supply 4 for AC 100V, 200V, etc.
An input circuit 11 that is connected to the input circuit 11 that determines the voltage level of the input voltage and outputs a control signal when the input voltage exceeds the set value; Main circuit 13 and input circuit 11
The ignition circuit 12 outputs an ignition signal to the main circuit 13 according to the control signal output from the ignition circuit 12.

The input circuit 11 has a current limiting resistor R connected to the operating power source 4.₁
A diode bridge whose AC input terminal is connected via
DC circuit of the diode circuit DB and this diode bridge circuit DB
The smoothing capacitor C connected between the output terminals and this smoothing capacitor
Two capacitors connected in series between both terminals of the capacitor C
Zener diode ZD and resistor R₂And smooth condensate
At one end of the connection point between the C and Zener diode ZD
Current limiting resistance R with a child connected₃And its cathode is smooth
Capacitor C and resistor R₂Connected to the connection point of its gate
Is a Zener diode ZD and a resistor R₂Connected to the connection point of
Current limiting resistor R₃The other of
Connected between the terminal of and the anode of the thyristor THY
Indicated as ON / OFF of thyristor THY
The control signal is output. The main circuit 13 is a three-phase main power
Bidirectional semiconductor switch connected in series with source 3 and load 2.
Touching element, eg TRIAC TRC,
The arc circuit 12 is provided between both terminals of the TRIAC TRC.
Resistor R connected in series _Five， Photo coupler PC fo
Totriac and resistance R₆Made of this photo card
The photodiode of the plastic PC is the current limiting resistance of the input circuit 11.
R₃Between the other terminal of the thyristor and the anode of the thyristor THY
Connected to the phototriac of the photocoupler PC
Resistance R₆Connection point is connected to the gate of TRIAC TRC
It is composed of a series circuit that has been connected.

The operation of the contactless switch circuit device 10 is as follows. In FIG. 2, when the level of the input voltage from the operation power supply 4 exceeds the set value, that is, the voltage of the DC output terminal of the diode bridge DB of each contactless switch 1 (1A, 1B, 1C) is the voltage of the Zener diode ZD. by weight, it causes a voltage drop across a current to the resistor R ₂ flows both terminals of the resistor R _2. This voltage drop turns on the thyristor THY, and a control current flows through the photodiode of the photocoupler PC. This allows the photo coupler PC
The phototriac is turned on, and a current flows through the resistor R ₆ , causing a voltage drop between both terminals of the resistor R ₆ . Due to this voltage drop, the triac TRC is turned on and the main power supply U,
The V and W phases are closed, and the load 2 such as a three-phase induction motor is driven.

[0006]

In the above-mentioned contactless switch circuit device, the three contactless switches connected in series with each phase of the three-phase main power supply and the load are affected by variations in characteristics between them. There may be variations in their closing times. When the closing times of these contactless switches vary, an unbalanced current flows in each phase of the load. This is especially problematic, for example, when the load starts a three-phase induction motor. That is, since the three-phase induction motor is almost in a short-circuit state at the beginning of startup, the three-phase main power supply voltage drops greatly when the contactless switch circuit device is closed, and then gradually recovers as the motor rotation increases and the normal voltage is restored. Return to power supply voltage. Further, since the operating power source is usually the three-phase main power source, the same voltage transition is followed. Then, for example, when two of the three contactless switches are closed first, the three-phase induction motor is in open-phase operation, and a starting current of 6 to 8 times the rated current flows. On the other hand, the voltage of the operation power supply decreases due to the decrease of the three-phase main power supply voltage, and the voltage of this operation power supply does not rise at all due to the open-phase operation of the three-phase induction motor. Without closing the circuit, a starting current of 6 to 8 times the rated current will continue to flow, and in some cases a serious accident leading to overheating and burning may occur. Further, if the starting current of 6 to 8 times the rated current continues to flow in this way, the main power supply is also adversely affected.

An object of the present invention is to match the closing times of the contactless switches in a contactless switch circuit device composed of a plurality of contactless switches.

[0008]

In order to achieve the above-mentioned object, a contactless switch circuit device according to the present invention comprises a plurality of contactless switch circuit devices for controlling the opening and closing of a main power supply line by turning on and off bidirectional semiconductor switching elements. These non-contact switches are connected to the operating power supply, each of which is connected to the operation power supply, judges the voltage level of the input voltage, and outputs a control signal when the set value is exceeded, and the main power supply and the load are connected in series. Connected, for example, a main circuit having a bidirectional semiconductor switching element composed of a triac, an ignition circuit for outputting an ignition signal to the main circuit by a control signal output from the input circuit, and an output from the input circuit And a control signal terminal for extracting the control signal to the outside, and these control signal terminals are connected in parallel.

[0009]

In the contactless switch circuit device of the present invention, each of the plurality of contactless switches is provided with a control signal terminal for extracting the control signal output from the input circuit to the outside, and these control signal terminals are connected in parallel. If these control signal terminals are connected in parallel, the contactless switch that outputs the control signal earlier among other contactless switches will also operate the other contactless switches. The closing times of all contactless switches will be the same.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram when a load such as a three-phase induction motor is driven using the contactless switch circuit device of the present invention. The contactless switch circuit device 10 of the present invention shown in FIG.
2 is different from the conventional contactless switch circuit device 10 shown in FIG. 2 in that each of the contactless switches 1 (1A, 1B, 1C) draws out the control signal output from the input circuit 11 thereof to the outside. A control signal terminal 14 is provided and these control signal terminals 14 are connected in parallel. These control signal terminals 14 are drawn from the anode of the thyristor THY of the input circuit 11 in FIG. This thyristor THY is a load connected between the other terminal of the current limiting resistor R ₃ and this thyristor THY, as described in the section of the prior art, in this case, a photocoupler PC of the ignition circuit 12. For diodes, this thyristor THY
Outputs a control signal indicated as ON / OFF. Therefore, the control signal terminal led out from the anode of the thyristor THY outputs a control signal indicated as ON / OFF of the thyristor THY.

The operation of the contactless switch circuit device 10 is as follows. In FIG. 1, when the level of the input voltage from the operation power supply 4 exceeds the set value, that is, the voltage of the DC output terminal of the diode bridge DB of each contactless switch 1 (1A, 1B, 1C) is the voltage of the Zener diode ZD. by weight, it produces a voltage between the current to the resistor R ₂ flows both terminals of the resistor R _2, the thyristor TH by the voltage drop
Y turns on. However, variations in the characteristics of the Zener diode ZD, the thyristor THY, etc. cause variations in the turn-on of the thyristor THY of each contactless switch 1 (1A, 1B, 1C), for example, the thyristor THY of the contactless switch 1A is turned on first. If current flows through the photodiode of the photocoupler PC and the triac TRC of the contactless switch 1A is turned on, the thyristors THY of the other contactless switches 1B and 1C are not turned on at this time, but Photocoupler PC for contact switches 1B and 1C
A control signal for the thyristor THY of the contactless switch 1A is applied to each of the photodiodes through the synchronous terminal 11, a control current flows through the thyristor THY, and the phototriac of the photocoupler PC is turned on. As a result, the triac TRCs of the non-contact switches 1B and 1C are turned on, and the closing times of the non-contact switches 1A, 1B and 1C become the same.

Since the closing times of the contactless switches coincide with each other as described above, when the load is a three-phase induction motor as described above, for example, two of the three contactless switches are closed first. Then, the 3-phase induction motor will be in open-phase operation, and the rated 6
~ 8 times the starting current flows, while the voltage of the operating power supply drops due to the decrease of the three-phase main power supply voltage. This operating power supply voltage does not rise because the three-phase induction motor is in open phase operation. The contactless switch does not close forever and the starting current of 6 to 8 times of this rating continues to flow, and in some cases overheat
Serious accidents leading to burnout are prevented.

In the embodiment shown in FIG. 1, the operation power source 4 is AC and is rectified by the diode bridge DB to be DC, but the same circuit can be applied even if the operation power source is DC. Further, FIG. 1 describes the case of driving the three-phase induction motor, but it is needless to say that the same effect can be obtained with a two-phase or six-phase multi-phase induction motor. Further, even when the non-contact switches are connected in parallel to increase the current capacity, the closing currents coincide with each other, so that the energizing current can be made uniform.

[0014]

According to the present invention, in a contactless switch circuit device comprising a plurality of contactless switches, the closing times of these contactless switches are controlled so as to coincide with each other.
Unbalanced current flowing through the load is prevented due to the variation in closing time of each contactless switch. This is especially true when the load is a multi-phase induction motor, and due to variations in the closing time, phase-out operation occurs and a starting current that is 6 to 8 times the rated current continues to flow, and in some cases a serious accident that may result in overheating or burnout is prevented. It Further, the adverse effect on the power supply due to the fact that the starting current of 6 to 8 times the rated current continues to flow is prevented, and the effect is great.

[Brief description of drawings]

FIG. 1 is a circuit diagram for driving a load such as a three-phase induction motor according to an embodiment of a contactless switch circuit device of the present invention.

FIG. 2 shows a conventional contactless switch circuit device, for example, 3
Circuit diagram for driving loads such as phase induction motors

[Description of symbols] 1 non-contact switch 1A non-contact switch 1B non-contact switch 1C non-contact switch 2 load (three-phase induction motor) 3 power supply (three-phase power supply) 4 operating power supply 10 non-contact switch circuit device 11 Input Circuit 12 Firing Circuit 13 Main Circuit 14 Control Signal Terminal TRC Bidirectional Switching Element (Triac)

Claims (3)

[Claims] 1. A bidirectional semiconductor switching device is turned on.
It consists of multiple non-contact switches that control the opening and closing of the main power line by turning them off. These non-contact switches are connected to the operating power supply, respectively, and judge the voltage level of the input voltage. And a main circuit having a bidirectional semiconductor switching element connected in series with a main power supply and a load, and an ignition circuit for outputting an ignition signal to the main circuit according to a control signal output from the input circuit. And a control signal terminal for pulling out a control signal output from the input circuit to the outside, the control signal terminals being connected in parallel, a contactless switch circuit device. 2. The contactless switch circuit device according to claim 1, wherein the bidirectional semiconductor switching elements of each main circuit of the plurality of contactless switches are multi-phase main power supplies and multi-phase induction motor phases. A contactless switch circuit device characterized in that it is connected in series with. 3. The contactless switch circuit device according to claim 1, wherein a bidirectional semiconductor switching element of each main circuit of the plurality of contactless switches is a triac. Switch circuit device.