JPH08205393A - Surge absorber - Google Patents

Abstract

PURPOSE: To realize a surge absorber capable of passing a withstand voltage test obtained by the electrical Appliance and Material Control Law, without cutting off a wire between the surge absorber and the ground beforehand. CONSTITUTION: A surge absorber has a surge absorbing section 14 provided with a pair of connected-in-series substances 24 composed of varistors 20 and arrestors 22 with built-in varistors, and a power relay section 16 provided with an electromagnetic coil 46, a fixed contact 48, and a movable contact 50. One end of each connected-in-series substance 24 is connected to one of a pair of power lines L1, L2 leading to an electronic circuit 68 to be protected respectively, and the other end is connected to the base end of the fixed contact 48. The base end of the movable contact 50 is connected to the ground G, and both ends of the electromagnetic coil 46 are connected to the power lines L1, L2. Accordingly, between the movable contact 50 and the fixed contact 48 is short-circuited when the electromagnetic coil 46 is excited, and between the movable contact 50 and the fixed contact 48 is interrupted when the electromagnetic coil 46 is de-energized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention absorbs a transient abnormal voltage or a surge such as induced lightning that enters an electronic device through a power line or the like, thereby protecting an electronic circuit element or the like of the electronic device. Regarding surge absorbers.

[0002]

2. Description of the Related Art Conventionally, in order to protect an electronic circuit element from a surge such as a transient abnormal voltage or inductive lightning that enters an electronic device through a power line or the like, various surge absorption measures are provided in the preceding stage of the electronic circuit. Has been applied. FIG. 6 shows an example of the surge absorber 70 in front of the electronic circuit 68 of the electronic device.
Is inserted. The surge absorber 70 includes a pair of series connection bodies 24 of a varistor 20 and a varistor built-in arrester 22. Each series connection body 24 is connected between the power supply lines L1 and L2 leading to the electronic circuit 68 and the ground G. Each is inserted and connected. Then, when a common mode surge that conducts between the line and ground is applied to the power supply lines L1 and L2, the varistor 20 and the varistor built-in arrester 22 operate and let them escape to the ground G side. is there.

[0003]

The operating voltage of the varistor 20 and the arrester 24 with a built-in varistor can be surely set in consideration of the voltage value (3000 V or less) of a general induced lightning surge that occurs as a natural phenomenon. 2 each to be absorbed
It should be set to about 00 to 800V. However, a device that requires a power supply is subject to a withstand voltage test stipulated in the Electrical Appliance and Material Control Law, and in the withstand voltage test, the power supply lines L1 and L2 are short-circuited and then AC 1200V is applied.
(In case of AC100V power supply) or AC1500V
Since the overvoltage (in the case of AC200V power supply) is applied for 1 minute, if a surge absorbing member having an operating voltage lower than this is connected, each member operates due to the execution of this withstand voltage test and the current flows. It will flow and as a result will fail the test. Therefore, in the past, in order to prevent the surge absorber 70 from operating in this withstand voltage test,
In advance, each surge absorbing member (series connection body 24) and ground G
There was a break in the wire and reconnection after the test.

However, re-connection between each surge absorbing member and the ground G after the end of the withstand voltage test is not only a troublesome work, but also it is shipped without forgetting the connection, and the protected electronic equipment. There is a risk that the surge absorber does not operate during actual use of the device and the electronic circuit of the electronic device cannot be effectively protected.

The present invention has been made in view of the above problems of the conventional example, and can pass the withstand voltage test stipulated by the Electrical Appliance and Material Control Law without disconnecting the surge absorber and the ground in advance. The purpose is to realize a surge absorber.

[0006]

SUMMARY OF THE INVENTION The surge absorber according to the present invention is a surge absorber connected between a pair of power supply lines leading to an electronic circuit to be protected and a ground, one end of which is the power supply. A pair of surge absorbing members connected to the wires, an electromagnetic coil having both ends connected to each power supply line, one connected to the other end of each surge absorbing member and the other connected to the ground, Excitation /
It is characterized in that it is provided with a pair of contacts that can be switched between short circuit and open circuit depending on a change in degaussing state. Another surge absorbing member may be inserted and connected between one ends of the surge absorbing member. The "surge absorbing member" is a concept that includes not only a single surge absorbing element such as a varistor, an arrester, or a varistor built-in type arrester but also a series connection body of these surge absorbing elements. .

[0007]

The withstand voltage test of the Electrical Appliance and Material Control Law is carried out with the power supply lines short-circuited, so that there is zero voltage between the power supply lines and the electromagnetic coil is demagnetized. Therefore, the contacts are automatically opened, and the other ends of the surge absorbing members and the ground are disconnected. Therefore, even if the test voltage is applied, the surge absorbing member does not operate, and the current does not flow to fail the test.

On the other hand, when power is supplied for actual use of the protected electronic circuit after completion of the withstand voltage test, the electromagnetic coil is in an excited state and the contacts are automatically short-circuited. Since the other end of each surge absorption member is connected to the ground, common mode /
Even if a surge enters, the surge absorbing member operates and can be surely released to the ground side.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a surge absorber 10 according to the present invention is roughly divided into a surge absorbing portion 14, a power relay portion 16 and a rectifying portion 18 which are housed in a housing 12.

The surge absorbing portion 14 is provided with a pair of serially connected bodies 24 of a varistor 20 and a varistor built-in arrester 22 as surge absorbing members, and one end of each serially connected body 24 is
It is connected to the first external terminal 26 and the second external terminal 28 led out of the housing 12. The varistor 20 is shown in FIG.
As shown in, electrode plates 32 are attached to both surfaces of a voltage nonlinear resistor 30 such as zinc oxide, and lead terminals 34 are connected to the outer surface of each electrode plate 32. Built-in varistor type arrester
As shown in FIG. 3, a pair of cap-shaped electrodes 38 made of a metal material having a good discharge characteristic are fitted in openings at both ends of a cylindrical body 36 made of an insulating material, and 22 are sealed with a sealing material 40. Xe, Ne, Ar, H
While filling the discharge gas mainly composed of rare gas such as e,
A voltage non-linear resistor 30 is connected between the inner surfaces of the cap-shaped electrode 38. The lead terminals 34 are connected to the outer surface of the cap-shaped electrode 38, and a discharge gap 44 is formed between the tips of the cap-shaped electrodes 38. The arrester 22 with a built-in varistor is capable of exhibiting excellent surge absorption characteristics that combine the quick response of the varistor and the large current resistance of the arrester. The rated voltage of the varistor 20 and the varistor built-in arrester 22 is, for example, in the range of 220V to 400V when the AC100V power supply is in mind, or in the range of 400V to 800V when the AC200V power supply is in mind. Is set.

The power relay section 16 includes an electromagnetic coil 46.
A fixed contact 48 and a movable contact 50. The base end 48a of the fixed contact 48 is connected to each of the series connection members of the surge absorbing section 14 described above.
It is connected to the other end of 24. In addition, the base end 50 of the movable contact 50
A is rotatably supported and is connected to the third external terminal 52. When a predetermined DC voltage is applied to both ends of the electromagnetic coil 46, the electromagnetic coil 46 is excited and the iron piece 50b of the movable contact 50 is attracted to the electromagnetic coil 46 side. Therefore, between the fixed contact 48 and the movable contact 50. Will be short-circuited. on the other hand,
When the voltage is no longer applied to both ends of the electromagnetic coil 46, the electromagnetic coil 46 is demagnetized and the movable contact 50 is returned to its original position by the biasing of the spring 54, so that the contact between the two is opened.

The rectifying section 18 comprises a bridge diode 56, and the input terminals 56a, 56 of the bridge diode 56 are provided.
b is connected to the fourth external terminal 58 and the fifth external terminal 60, respectively, and the output terminals 56c and 56d are connected to both ends of the electromagnetic coil 46 of the power relay section 16, respectively. Further, the electrolytic capacitor 62 is connected in parallel with the electromagnetic coil 46.

FIG. 4 is a circuit diagram showing an example of connection of the surge absorber 10, which includes a first external terminal 26 and a second external terminal 28.
Are connected to the power supply lines L1 and L2, respectively, the fourth external terminal 58 and the fifth external terminal 60 are also connected to the power supply lines L1 and L2, and the third external terminal 52 is grounded to the ground G.
Further, another varistor 20 is interposed between the power supply lines L1 and L2, and the power supply line L1 has a fuse 64 for breaking overcurrent.
However, a power switch 66 is connected in series to the power line L2.

When the power switch 66 is turned on to start the supply of AC power to the electronic circuit 68 of the protected electronic device, a DC voltage is applied to both ends of the electromagnetic coil 46 via the rectifying unit 18, Since the electromagnetic coil 46 is excited, the movable contact 50 and the fixed contact 48 are short-circuited, resulting in the surge absorbing portion.
Each series connection body 24 of 14 is connected between the power line L1 and the ground G and L2.
-It will be connected between ground G. Therefore,
In this state, when a common mode surge is applied between the power supply line L1 and the ground G, or between the L2 and the ground G, the series connection body 24 operates and the surge becomes the ground G.
It will be escaped to the side. When a normal mode surge that reciprocates between the power supply lines L1 and L2 is applied, the varistor 20 inserted between the power supply lines L1 and L2 operates to absorb the surge. Next, when the power switch 66 is turned off to stop the power supply to the electronic circuit 68, no voltage is applied to both ends of the electromagnetic coil 46, and the electromagnetic coil 46 is demagnetized to move the movable contact 50 and the fixed contact 48.
Since the space is open, each series connection body 24 of the surge absorber 14
Will be separated from the ground G.

By the way, since the withstand voltage test of the Electrical Appliance and Material Control Law is carried out with the power source lines L1 and L2 short-circuited, the potential between the power source lines L1 and L2 is zero. Therefore, during the withstand voltage test, the electromagnetic coil 46 is demagnetized and the movable contact 50 and the fixed contact 48 are open, so that the power supply line L
The series connection bodies 24 connected to 1 and L2 and the ground G are also disconnected. Therefore, even if a test voltage of 1200 V or 1500 V in the withstand voltage test is applied between the power supply line L1 and the ground G and between the power supply line L2 and the ground G, the series connection bodies 24 of the surge absorbing unit 14 do not operate, and the current flows. The test does not fail because it does not flow.

On the other hand, after the withstand voltage test is completed, if the power switch 66 is turned on when the protected electronic device is used, the electromagnetic coil 46 is excited and the movable contact 50 and the fixed contact 48 are short-circuited. Each of the 14 series-connected bodies 24 is automatically connected to the ground G. Therefore, when a common mode surge such as induced lightning is applied in this state, each series connection body 24 of the surge absorbing portion 14 operates, and the surge can be surely released to the ground G side.

A surge absorbing portion in this surge absorber 10
The configuration of 14 is not limited to the above. For example, as shown in FIG. 5, the pair of varistor 20 is connected to the first external terminal 26.
And the second external terminal 28 and the fixed contact 48, respectively, and connect the other varistor 20 to one end of each varistor 20.
May be inserted and connected. In this case, the first external terminal
If the 26th to 5th external terminals 60 are connected in the same manner as in FIG. 4, not only the varistor 20 as a surge absorbing member is inserted between the power supply lines L1 and L2 and the ground G, but also between the power supply lines L1 and L2. Also, the varistor 20 will be inserted. Alternatively, instead of the varistor 20 and the varistor built-in arrester 22, a normal arrester may be used to configure the surge absorber 14.

[0018]

In the surge absorber according to the present invention,
When carrying out the withstand voltage test of the Electrical Appliance and Material Control Law, the surge absorbing member and the ground are automatically separated from each other, so that the test can be passed without intentionally disconnecting the surge absorbing member and the ground in advance. After the test,
When the power supply to the protected electronic circuit is started, the surge absorbing members and the ground are automatically connected, so that the protected electronic circuit can be effectively protected from the surge.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a surge absorber according to the present invention.

FIG. 2 is a sectional view showing a varistor used in the surge absorber.

FIG. 3 is a cross-sectional view showing a varistor built-in arrester used in the surge absorber.

FIG. 4 is a circuit diagram showing a connection example of the surge absorber.

FIG. 5 is a circuit diagram showing a modified example of the surge absorber.

FIG. 6 is a circuit diagram showing a conventional surge absorber.

[Explanation of symbols]

 10 Surge absorber 20 Varistor 22 Varistor built-in arrester 24 Series connection body 46 Electromagnetic coil 48 Fixed contact 50 Moving contact 68 Protected electronic circuit L1, L2 Power supply line G Ground

Claims (2)

[Claims] 1. A surge absorber connected between a pair of power supply lines communicating with a protected electronic circuit and a ground, a pair of surge absorption members each having one end connected to the power supply line, and both ends having each power supply. An electromagnetic coil connected to each of the wires, and a pair of contacts, one of which is connected to the other end of each surge absorbing member and the other of which is connected to the ground, and which is switched between short-circuiting and opening depending on the change of the excitation / demagnetization state of the electromagnetic coil. And a surge absorber. 2. The other surge absorbing member is inserted and connected between one ends of the surge absorbing member.
Surge absorber described in.