JP2741661B2 - Surge absorber - Google Patents

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 an induced lightning which penetrates an electronic device through a power supply line or the like, thereby protecting an electronic circuit element or the like of the electronic device. Related to surge absorbers.

[0002]

2. Description of the Related Art Conventionally, in order to protect electronic circuit elements and the like from transient abnormal voltages and surges such as induced lightning that enter a electronic device through a power supply line or the like, various surge absorbing measures are provided in a preceding stage of the electronic circuit. Has been given. FIG. 6 shows an example of this, in which a surge absorber 70 is provided before the electronic circuit 68 of the electronic device.
Is inserted. The surge absorber 70 includes a pair of varistors 20 and varistor built-in arresters 22 connected in series. Each series connected body 24 is connected between the power lines L1 and L2, which lead to the electronic circuit 68, and the ground G. Each is inserted and connected. When a common mode surge that is conducted between the power supply lines L1 and L2 is applied to the power supply lines L1 and L2, the varistor 20 and the varistor built-in arrester 22 operate and escape to the ground G side. is there.

[0003]

The operating voltage of the varistor 20 and the varistor with built-in varistor 24 can be reliably determined by taking into account the voltage value of a general induced lightning surge (3000 V or less) which occurs as a natural phenomenon. 2 each for absorption
It should be set to about 00 to 800V. However, equipment that requires a power supply is subjected to a withstand voltage test specified by the Electrical Appliance and Material Control Law. In the withstand voltage test, the power supply lines L1 and L2 are short-circuited and AC1200V is applied.
(AC100V power supply) or AC1500V
Since an overvoltage (in the case of a 200 V AC power supply) is applied for one minute, if a surge absorbing member having an operating voltage lower than this is connected, each member operates by performing the withstand voltage test and the current is reduced. It will flow and, as a result, will fail the test. For this reason, conventionally, in this withstand voltage test, the surge absorber 70 never operates,
In advance, each surge absorbing member (series connection body 24) and ground G
In some cases, the wires were disconnected, and the wires were reconnected after the test was completed.

However, it is not only time-consuming to reconnect each surge absorbing member and the ground G after the withstand voltage test, but also the electronic device to be protected is shipped after forgetting the connection. There is a danger that the surge absorber does not operate during the actual use of the electronic device, and the electronic circuit of the electronic device cannot be effectively protected.

The present invention has been made in view of the above-mentioned problems of the prior art, and can pass a withstand voltage test specified by the Electrical Appliance and Material Control Law without disconnecting the surge absorber and the ground in advance. It is intended to realize a surge absorber.

[0006]

A surge absorber according to the present invention is a surge absorber connected between a pair of power lines leading to a protected electronic circuit and a ground, one end of which is connected to the power source. A pair of surge absorbing members connected to the power line, an electromagnetic coil having both ends connected to each power supply line, and one end connected to the other end of each surge absorbing member and the other end connected to the ground, Excitation /
And a pair of contacts that are switched between short-circuit / open according to a demagnetization state change. Another surge absorbing member may be inserted and connected between one end of the surge absorbing member. The “surge absorbing member” is a concept including not only a single surge absorbing element such as a varistor or an arrestor, or a varistor built-in type arrestor, but also includes a series connection of these surge absorbing elements. .

[0007]

Since the withstand voltage test according to the Electrical Appliance and Material Control Law is performed with the power supply lines short-circuited, the voltage between the power supply lines becomes zero, and the electromagnetic coil is demagnetized. Therefore, the contacts are automatically opened, and the other end of each surge absorbing member is separated from the ground. Therefore, even if the test voltage is applied, the surge absorbing member does not operate, and the current does not flow and the test is not rejected.

On the other hand, when power is supplied for the actual use of the protected electronic circuit after the withstand voltage test is completed, the electromagnetic coil is energized and the contacts are automatically short-circuited, Since the other end of each surge absorbing member is connected to the ground, common mode
Even if a surge enters, the surge absorbing member operates and can reliably escape 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 section 14, a power relay section 16, and a rectifying section 18 housed in a housing 12.

The surge absorber 14 includes a pair of a series connection 24 of a varistor 20 and a varistor built-in arrester 22 as a surge absorption member. One end of each series connection 24 is
It is connected to a first external terminal 26 and a second external terminal 28 led out of the housing 12. The varistor 20 is shown in FIG.
As shown in FIG. 5, electrode plates 32 are adhered to both surfaces of a voltage non-linear resistor 30 such as zinc oxide, and lead terminals 34 are connected to the outer surfaces of the respective electrode plates 32. Arrester with built-in varistor
As shown in FIG. 3, a pair of cap-shaped electrodes 38 made of a metal material having good discharge characteristics are fitted into openings of both ends of a cylindrical body 36 made of an insulating material as shown in FIG. Xe, Ne, Ar, and H are placed in an airtight container 42 hermetically sealed.
While filling with a discharge gas mainly composed of a rare gas such as e,
A voltage non-linear resistor 30 is connected between the inner surfaces of the cap-shaped electrode 38. Lead terminals 34 are respectively connected to the outer surfaces of the cap-shaped electrodes 38, and a discharge gap 44 is formed between the tips of the cap-shaped electrodes 38. The varistor-incorporated arrester 22 is capable of exhibiting excellent surge absorption characteristics having both the varistor responsiveness and the arrester's large current capacity. The rated voltage of the varistor 20 and the built-in varistor 22 is, for example, in the range of 220 V to 400 V when an AC 100 V power supply is considered, and in the range of, for example, 400 V to 800 V when an AC 200 V power supply is considered. 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.
24 is connected to the other end. In addition, the base 50 of the movable contact 50
a is rotatably supported on the shaft 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. Will be short-circuited. on the other hand,
When no voltage is applied to both ends of the electromagnetic coil 46, the electromagnetic coil 46 is demagnetized and the movable contact 50 returns to the original position by the bias of the spring 54, so that the contact between the two contacts is opened.

The rectifier 18 includes a bridge diode 56, and the input terminals 56a, 56a of the bridge diode 56.
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 unit 16, respectively. An electrolytic capacitor 62 is connected in parallel to the electromagnetic coil 46.

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

When the power switch 66 is turned on to start supplying 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 rectifier 18, Since the electromagnetic coil 46 is excited, the movable contact 50 and the fixed contact 48 are short-circuited, and as a result, the surge absorbing portion
14 are connected in series between the power line L1 and the ground G and between
-To be connected between the 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 L2 and the ground G, the series-connected body 24 operates and the surge is applied to the ground G.
It will be escaped to the side. When a normal mode surge that reciprocates between the power lines L1 and L2 is applied, the varistor 20 inserted between the power lines L1 and L2 operates to absorb the surge. Next, when the power switch 66 is turned off to stop supplying power to the electronic circuit 68, no voltage is applied to both ends of the electromagnetic coil 46, the electromagnetic coil 46 is demagnetized, and the movable contact 50 and the fixed contact 48 are demagnetized.
Since the gap is opened, each series connection body 24 of the surge absorber 14 is
Is separated from the ground G.

Since the withstand voltage test according to the Electrical Appliance and Material Control Law is performed with the power supply lines L1 and L2 short-circuited, the potential between the power supply lines L1 and L2 is zero potential. Accordingly, during the withstand voltage test, the electromagnetic coil 46 is in a demagnetized state, and the movable contact 50 and the fixed contact 48 are open.
1, the series connection bodies 24 connected to L2 and the ground G are also disconnected. For this reason, 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 L2 and the ground G, the respective series-connected members 24 of the surge absorbing unit 14 do not operate, and the current is reduced. The test does not fail because it does not flow.

On the other hand, if the power switch 66 is turned on when the protected electronic device is used after the withstand voltage test is completed, 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 an induced lightning is applied in this state, each series-connected body 24 of the surge absorber 14 operates, and the surge can be reliably released to the ground G side.

The surge absorber in the surge absorber 10
The configuration of 14 is not limited to the above. For example, as shown in FIG. 5, a pair of varistors 20 are connected to first external terminals 26.
And between the second external terminal 28 and the fixed contact 48, and the other varistor 20 is connected between one end of each varistor 20.
May be inserted and connected. In this case, the first external terminal
When the 26th to fifth 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 lines L1, L2 and the ground G, but also between the power lines L1, L2. The varistor 20 is also inserted. Alternatively, instead of the varistor 20 and the varistor built-in arrester 22, the surge absorber 14 may be configured using a normal arrester.

[0018]

In the surge absorber according to the present invention,
When conducting a withstand voltage test according to the Electrical Appliance and Material Control Law, each surge absorbing member and the ground are automatically separated, so that the test can be passed without the need to disconnect the surge absorbing member and the ground in advance. After the test,
When the power supply to the protected electronic circuit is started, the connection between each surge absorbing member and the ground is automatically established, so that the protected electronic circuit can be effectively protected from the surge.

[Brief description of the 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 sectional view showing a varistor built-in arrester used for 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 Built-in varistor arrestor 24 Series connection 46 Electromagnetic coil 48 Fixed contact 50 Moving contact 68 Protected electronic circuit L1, L2 Power line G Ground

Claims (2)

(57) [Claims] 1. A surge absorber connected between a pair of power supply lines leading to a protected electronic circuit and a ground, a pair of surge absorbing members having one end connected to the power supply line, and both ends connected to a power supply. An electromagnetic coil connected to each of the wires, and a pair of contacts connected to the other end of each surge absorbing member and the other connected to the ground, and to switch between short-circuiting / opening according to a change in the excitation / demagnetization state of the electromagnetic coil. And a surge absorber. 2. The surge absorbing member according to claim 1, wherein another surge absorbing member is inserted and connected between one end of the surge absorbing member.
The surge absorber according to the above.