JPS63157410A - Electromagnet apparatus - Google Patents

Abstract

PURPOSE:To prevent malfunction and burning of an operation coil by providing serially connected bias resistor, a light emitting diode of photocoupler and a nonlinear element which shows a low impedance at a voltage higher than the limited voltage between the DC output terminals of full-wave rectifier. CONSTITUTION:A Zener diode 14 is connected in series to a light emitting diode 10 of photocoupler 8. A Zener voltage of the Zener diode 14 is selected so that it is lower than a DC voltage applied to the Zener diode 14 corresponding to total voltage of AC voltage to be input to a full-wave rectifier 1 through a changeover switch 3 and is higher than a DC voltage applied to the Zener diode 14 corresponding to an AC voltage branched through a capacitor 4 and a resistor 5. Thereby, a current is caused to flow into a light emitting diode while the movable iron core is attracted and the current flowing in to the light emitting diode can be perfectly cut off while the iron core is held, thus forming a series circuit of operation coils 2a and 2b reliably. Moreover malfunction and reduction of holding current can be reduced and burning and deterioration of insulation property of coil 2b can be also be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an AC-operated DC-excited electromagnet device used, for example, in an electromagnetic contactor, and in particular to prevention of malfunction of an operating coil.

[Conventional technology]

Fig. 2 is a circuit diagram showing a conventional 'r4 magnet device disclosed in Japanese Utility Model Application Publication No. 59-59448. 2 is a full-wave rectifier, 2 is an operating coil through which the direct current output from the full-wave rectifier 1 is applied, 3 is a delay type changeover switch connected to the AC side of the full-wave rectifier 1, 4 is a capacitor, and 5 is a resistor. .

In the conventional electromagnet device configured as described above,
When AC voltage is applied and turned on, current flows to the operating coil 2 via the changeover switch 3 and the full-wave rectifier 1, the operating coil 2 is excited, and the movable core is attracted to a fixed core (not shown) to which the operating coil 2 is attached. do. The changeover switch 3 operates in conjunction with the suction operation of the movable core, and its contacts open immediately before the movable core attracts the fixed core. Therefore, after the movable core is attracted to the fixed core, a voltage is applied to the operating coil 2 via the capacitor 4, the resistor 5, and the full-wave rectifier 1.
Holding is achieved with small coil power consumption.

When the voltage applied to the operating coil 2 is removed, the operating coil 2
The flywheel circuit shown by the arrow 6 in Fig. 2 is formed by the inductance energy, the current in the operating coil 2 is attenuated, and when the attractive force becomes lower than the repulsive force of a tripping spring (not shown), the movable iron core returns to the fixed iron core. be freed from

Since the conventional electromagnetic device described above has only one operating coil 2, it is necessary to increase the magnetomotive force in order to obtain a large attraction force when it is turned on.As a result, the power consumed by the operating coil 2 during holding is large. It had the disadvantage of becoming. In order to improve this shortcoming, the applicant has proposed an electromagnet device in which the operating coil is divided into two as shown in Fig. 3, and the current is switched between when the movable core is attracted and when it is held. 61-125804). In Figure 3, 1°3~
5 is exactly the same as that shown in FIG. 2a
is a first operating coil whose one end is connected to the positive side of the DC output terminal of the full-wave rectifier 1; 2b is a second operating coil connected in series with the first operating coil 2a; The DC resistance of the coil 2b is smaller than that of the first operating coil 2a.

Reference numeral 7 denotes a transistor whose collector and emitter are connected in parallel with the first operating coil 2a, and the base of the transistor 7 is connected to the emitter of a phototransistor 9 built into a photocoupler 8. 10 is a light emitting diode of the photocoupler 8, 11 is a bias resistor, 12 is a protective resistor, and 13 is a protective varistor. In the electromagnet device configured as above, when the movable iron core is attracted, the changeover switch 3 is connected to the AC power source. A single-phase alternating current voltage is applied to the full-wave rectifier 1 through the converter, and the direct current rectified by the full-wave rectifier 1 flows through the bias resistor 11 to the light-emitting diode 10, and an optical signal from the light-emitting diode 10 is transmitted to the phototransistor 9. Sent. This optical signal causes conduction between the collector and emitter of the phototransistor 9, and a base voltage is applied to the base of the transistor 7, causing conduction between the collector and emitter of the transistor 7. A supply current is applied to the operating coil 2b.

When the delayed operation type changeover switch 3 is opened just before the movable core is attracted by the attraction force generated by this input current and is attracted to the fixed core, the AC voltage supplied from the AC power source is divided by the capacitor 4 and the resistor 5. The AC voltage applied to the full-wave rectifier 1 is reduced. Therefore, the DC voltage output from the full-wave rectifier 1 also drops, and the light emitting diode 1
The current flowing through the phototransistor 9 is also reduced and no optical signal is output, making the collector and emitter of the phototransistor 9 non-conductive. Therefore, the first operating coil 2a and the second operating coil 2b are connected in series, and the holding state is maintained with a small holding current.

[Problem that the invention seeks to solve]

The photocoupler 8 used in the i-magnet device shown in FIG. This current is supplied to the base of the transistor 7. A current with an amplification factor corresponding to this base current flows between the collector and emitter of the transistor 7. Therefore, regardless of the voltage fluctuation of the AC power supply, the DC output of the full-wave rectifier I The voltage decreases and the light emitting diode lO
Even if the current flowing through the coil 2a becomes small, the current amplified by the transmissibility of the photocoupler 8 and the amplification factor of the transistor 7 flows between the collector and emitter of the transistor 7, and the complete first operation coil 2a and second operation coil 2a A case may arise in which a series circuit of the coil 2b is not configured. As a result, a high voltage continues to be applied to the second operating coil 2b, causing problems such as burnout and insulation deterioration of the second layer coil 2b.

The present invention has been made in order to improve such problems, and it is an object of the present invention to provide an electromagnet device that can prevent malfunctions, burnout, etc. of the operating coil.

[Means for solving problems]

Regarding this invention! The magnet device has a delayed operation type changeover switch on the AC side, a series-connected capacitor and a resistor connected in parallel with this changeover switch, and a first connection between the DC output terminals.
A bias resistor, a light emitting diode of a photocoupler, and a non-linear element having a characteristic of low impedance above a limit voltage are connected between the DC output terminals of a full-wave rectifier in which the operating coil and the second operating coil are connected in series, It is characterized in that a phototransistor of a photocoupler is connected to the base of a transistor whose first operating coil, collector, and emitter are connected in parallel.

[For production]

In this invention, when the changeover switch is opened just before the movable core is attracted to the fixed core, the voltage applied to the nonlinear element becomes equal to or less than the limit voltage of the nonlinear element divided through the capacitor and the resistor, and the nonlinear The element has high impedance, and the current flowing to the photocoupler's light emitting diode is cut off when it is held.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention. In the figure, 1 to 13 are the same as the example shown in FIG. The Zener voltage of the Zener diode 14 is lower than the DC voltage applied to the Zener diode 14 corresponding to the total voltage of the AC power input to the full-wave rectifier 1 via the changeover switch 3. , and is selected to be higher than the DC voltage applied to the Zener diode 14 in response to the AC voltage divided through the capacitor 4 and the resistor 5.

In the electromagnet device configured as described above, by turning on an external switch (not shown), a single-phase AC voltage is applied from the AC power source to the full-wave rectifier 1 via the changeover switch 3, and from the full-wave rectifier 1, the AC voltage is applied to the full-wave rectifier 1. A DC voltage corresponding to the total voltage of the source is output.

At this time, the voltage applied to the Zener diode 14 is
Zener diode 14
becomes a low impedance, and a current flows to the light emitting diode 10 of the photocoupler 8 via the bias resistor and the Zener diode 14.

The light emitting diode 10 emits an optical signal using this current, and sends the optical signal to the phototransistor 9. The collector and emitter of the phototransistor 9 are brought into conduction by the optical signal, and a base voltage is applied to the base of the transistor 7 to bring the collector and emitter of the transistor 10 into conduction.

Therefore, the full voltage is applied to the second operating coil 2b with low DC resistance via the transistor 10, and the second operating coil 2b is excited with a large attraction current.

When the movable iron core is attracted by the excitation of the second operation coil 2b and the changeover switch 3 is opened just before it is attracted to the fixed iron core, the AC voltage supplied from the AC power supply is applied to the changeover switch 3.
The AC voltage applied to the full-wave rectifier 1 is reduced by dividing the voltage by a capacitor 4 and a resistor 5 connected in parallel with the full-wave rectifier 1.

As a result, the DC voltage output by the full-wave rectifier l decreases,
The voltage applied to the Zener diode 14 becomes lower than the Zener voltage, and the Zener diode 14 becomes high impedance, completely blocking the current flowing through the light emitting diode 10. Therefore, an optical signal is no longer output from the light emitting diode 10, and the phototransistor 9 is also cut off.
The collector and emitter of the transistor 7 also become non-conductive, and the first operating coil 2a and the second operating coil 2b are completely connected in series and maintained. In this holding state, a voltage divided by the capacitor 4 and the resistor 5 is applied to the first operating coil 2a and the second operating coil 2b, so that a small holding current can flow.

Next, when the external switch is shut off, the applied voltage from the outside disappears and the first operating coil 2a and the second operating coil 2b
The inductance energy is consumed in the flyhole circuit formed between the full-wave rectifier 1, the current is rapidly attenuated, the holding force is weakened, and the movable core is released by a tripping spring (not shown).

In the above embodiment, a case was explained in which the Zener diode 14 was used as a non-linear element connected in series with the light emitting diode 10, but even if a varistor was connected in place of the Zener diode 14, the same operation as in the above embodiment would occur. can be done.

〔Effect of the invention〕

As explained above, this invention controls the current flowing to the light emitting diode of the photocoupler using a non-linear element that has low impedance above the limit voltage and high impedance below the limit voltage. It is possible to flow Ti current and completely cut off the current flowing to the light emitting diode during holding, thereby reliably constructing a series circuit of the first operating coil and second operating coil, preventing malfunction, holding @, and current flow. This has the effect of reducing burnout of the second operating coil and preventing insulation deterioration.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an embodiment of this invention, Figures 2 and 3 are
Each figure is a circuit diagram showing a conventional example. 1... Full wave rectifier, 2a...
...First operating coil, 2b... Second operating coil, 3... Changeover switch, 4.
......Capacitor, 5...Resistor, 7...Transistor, 8...
...Photocoupler, 9...Phototransistor, 10...Light-emitting diode,
11......Bias resistance, 14...
...Zener diode. Note that the same reference numerals in each figure indicate the same or corresponding parts. First cause Figure 2 Figure 3

Claims (4)

[Claims] (1) Delayed operation type in which the operating coil is divided into two parts, a first operating coil and a second operating coil connected in series, and a capacitor and a resistor connected in series from a single-phase AC power source are connected in parallel to the operating coil. In an electromagnetic device that applies full-wave rectification to the voltage supplied via a changeover switch, a series-connected bias resistor connected between the DC output terminals of the full-wave rectifier, a light-emitting diode of a photocoupler, and a low impedance above the limit voltage are used. A non-linear element having characteristics such that: a transistor whose collector and emitter are connected in parallel with the first operating coil;
An electromagnetic device comprising a phototransistor of the photocoupler described above, the collector of which is connected to the connection point of the operating coil and the full-wave rectifier via a protective resistor. (2) The limiting voltage of the non-linear element is higher than the DC output voltage of the full-wave rectifier, which is reduced by dividing the AC input voltage with a capacitor and a resistor when the changeover switch is open. electromagnetic device. (3) The electromagnet device according to claims 1 and 2, wherein the nonlinear element is a Zener diode. (4) The electromagnet device according to claims 1 and 2, wherein the non-linear element is a varistor.