JPH0824084B2 - Electromagnetic device drive circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit of an electromagnet device which is controlled by a programmable controller (hereinafter, simply referred to as a PC) or the like to control opening / closing of electric contacts.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional chopper type electromagnet device controlled by a PC and its drive circuit.
In FIG. 3, the electromagnet device 1 is driven by a drive circuit 7 including a power supply device 2, a voltage detection unit 3, a closing pulse unit 4, a holding pulse unit 5, and an output unit 6. The drive circuit 7 is connected to the control power supply 9 and the contact 10a of the relay 10 controlled by the PC 8 is connected in series to the AC power supply 11 via the diode D, and operates by turning on / off the contact 10a of the relay 10. The power supply device 2 of the drive circuit 7 lowers the voltage of the AC power supply 11 and applies an appropriate voltage to the drive circuit 7. The voltage detection unit 3 detects whether or not the power supply voltage has reached the voltage required to drive the electromagnet device 1, and turns on when the power supply voltage reaches the voltage required to drive the electromagnet device 1. A signal is supplied to the pulse unit 4. The closing pulse unit 4 generates a closing pulse having a pulse width of a predetermined time according to the signal from the voltage detecting unit 3 and applies the voltage of the AC power supply 11 to the electromagnet device 1 via the output unit 6 to operate the electromagnet device 1. Let Since the holding pulse unit 5 holds the electromagnet device 1 after the electromagnet device 1 operates, the holding pulse unit 5 outputs a holding pulse having a narrower pulse width than the input pulse and intermittently through the output unit 6.
Supply to.

In such a drive circuit 7, for example, when the contact 10a (R in FIG. 4) of the relay 10 is turned on as shown in FIG. The electric current I is supplied to the electromagnet device 1 to operate the electromagnet device 1, and then the intermittent electric current is supplied to the electromagnet device 1 by the holding pulse from the holding pulse unit 5 to hold the operation of the electromagnet device 1. When the contact 10a of the relay 10 is turned off, the holding pulse from the holding pulse section 5 disappears and the electromagnet device 1 is opened.

[0004]

Generally, the electromagnet device is constructed so that the movable core is attracted to the fixed core.
When the movable iron core is attracted to the fixed iron core, a gap is formed between the two iron cores and the magnetic path is open. Therefore, the current for operating the electromagnet device is 50% of the current for maintaining the operating state of the electromagnet device 1. A large current of up to 200 times flows. Therefore, the contact of the relay for turning on / off this current needs to be for a large current, and the relay for turning on / off this contact is inevitably large. Therefore, the relay controlled by the PC has a drawback that it is limited to a large relay having a contact with a large current capacity.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a drive circuit of an electromagnet device which can be controlled by a small relay having a contact with a relatively small current capacity. is there.

[0006]

In order to achieve the above object, the present invention provides a main power supply circuit composed of an electromagnet device and a main power supply connected to the electromagnet device, and a voltage obtained by stepping down the voltage of the main power supply circuit. And a drive circuit for driving the electromagnet device by a chopper method, the drive circuit having a voltage detection unit for detecting whether or not the power supply voltage has reached a predetermined voltage, and turning on the electromagnet device. Is connected to the input circuit of the voltage detection unit in the drive circuit that uses the voltage obtained by stepping down the voltage of the main power supply circuit as the circuit voltage.

[0007]

The present invention focuses on the fact that the drive circuit for driving the electromagnet device by the chopper method operates at a voltage and current smaller than the voltage and current of the main power supply circuit, and connects the contact of the relay to the drive circuit. Then, the input current of the drive circuit is turned on / off at this contact to operate the drive circuit, and the operation of this drive circuit turns on / off the electromagnet device.

[0008]

1 is a block diagram of a drive circuit of an electromagnet device showing an embodiment of the present invention. In the figure, the same parts as those of the conventional device shown in FIG. 3 are designated by the same reference numerals. FIG.
In the same manner as in the conventional device, the drive circuit 7 for driving the electromagnet device 1 connected to the main power supply circuit in which the diode D is connected in series to the AC power supply 11 is the power supply device 2, the voltage detection unit 3, the input pulse unit 4 , A holding pulse unit 5 and an output unit 6. The difference between this embodiment and the conventional device is that
This is that the contact 10a of the relay 10 controlled by the PC 8 and connected to the control power supply 9 is connected to the input circuit of the voltage detection unit 3 of the drive circuit 7. At this time, the contact 10a of the relay 10 is connected to the input circuit of the voltage detection unit 3 of the drive circuit 7 in which the voltage obtained by stepping down the voltage of the AC power supply 11 is used as the circuit voltage, thereby opening and closing the main power supply circuit. The relay 10 may be smaller than the current capacity of the contact, and the relay 10 is smaller than that of the conventional device shown in FIG.

When the relay 10 operates in response to a closing command from the PC 8, the contact 10a of the relay 10 closes the contact terminals S1 and S2 of the input circuit of the voltage detection unit 3 to close the voltage detection unit 3.
A voltage is applied to. The voltage detection unit 3 detects whether or not the applied voltage has reached the voltage required to turn on the electromagnet device 1, and the applied voltage has reached the voltage required to turn on the electromagnet device 1. Is detected,
A signal is given to the closing pulse unit 4. Since the operation of closing and holding the electromagnet device 1 by the chopper method by the operation of the closing pulse unit 4 and the holding pulse unit 5 is the same as the conventional device, the description thereof will be omitted.

As described above, the drive circuit 7 is an AC power source 11
Since the circuit circuit for which the voltage is reduced is used as the driving power source, the current flowing through the contact 10a of the relay 10 is small. Therefore, a semiconductor switch such as a transistor can be used instead of the contact 10a of the relay 10. For example, as shown in FIG. 2, the contact terminals S1 and S of the drive circuit 7 are
2, the optical signal introduced by the optical fiber 12 is converted into ON / OFF of the phototransistor by the photoelectric conversion device 13 including the phototransistor, and the drive circuit 7 is operated to drive the electromagnet device 1. it can.

[0011]

According to the present invention, the contact of the relay for operating the drive circuit of the electromagnet device is a drive circuit in which a current smaller than the current at the time of turning on the electromagnet device connected to the main power supply circuit flows. Since it is connected to the input circuit of the voltage detector, the current capacity of the relay contact may be small, and therefore a small relay can be used, and the voltage detector is also driven by the relay contact. Since the electromagnet device is driven only when the voltage of the power supply circuit has reached the voltage required to drive the electromagnet device, the voltage of the main power supply circuit does not reach the voltage required to drive the electromagnet device. Regardless, a driving signal is supplied from the drive circuit to the electromagnet device to prevent an erroneous operation such as an unstable operation of the electromagnet device. In addition, since the current capacity of the relay contacts is small, semiconductor switches such as transistors can be used in place of mechanical contacts, and the phototransistor is controlled by the optical signal derived from the optical fiber, which allows the drive circuit to operate. It has an effect that it can be operated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a drive circuit for an electromagnet device according to the present invention.

FIG. 2 is a block diagram showing a different embodiment of the drive circuit of the electromagnet device according to the present invention.

FIG. 3 is a block diagram showing a drive circuit of an electromagnet device in a conventional device.

FIG. 4 is a waveform diagram showing opening and closing of contacts and current thereof in FIG. 3 3 voltage detecting unit 4 applying pulse unit 5 holding pulse unit 7 driving circuit 8 programmable controller 10 relay 10a contact

Claims (1)

[Claims] 1. A drive for driving a main power supply circuit comprising an electromagnet device and a main power supply connected to the electromagnet device, and a voltage obtained by reducing the voltage of the main power supply circuit as a circuit voltage to drive the electromagnet device by a chopper method. This drive circuit has a voltage detection unit for detecting whether or not the power supply voltage has reached a predetermined voltage, and a signal contact unit from a signal source for instructing to turn on the electromagnet device is a main power supply circuit. A drive circuit for an electromagnet device, which is connected to an input circuit of a voltage detection unit in a drive circuit that uses a voltage obtained by stepping down a voltage as a circuit voltage.