JPS5928836A - Vertical surge protecting housing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides protection against vertical surges, such as lightning surges, that enter from the communication line or power line, in a case housing a communication device that is supplied with commercial power via a power line. This invention relates to a case grounding circuit for protecting a vertical column for use in a device with poor protection.

FIG. 1 is a circuit diagram showing an example of a configuration in which a conventional lightning surge protection measure is applied to a digital telephone terminal that is supplied with power from a commercial power source. In the figure, 1 is subscriber 4'
is a cheap device, 2 is a fuse, lj: neck saver, 4, 5 and 4
．． 5 is the communication line, 6-digit line termination device g7.7 is the housing of the line termination device 6, 8 is the telephone circuit, 9 is the 1L Tochi! A transformer, 10 is a telephone housing, 11 and 12 are commercial power lines, 13 is a pole transformer that supplies commercial power,
14, 15.16 are ground wires, 17, 18.19 respectively
are ground resistances, respectively.

Next, the operation will be explained. Now, if a surge enters from the communication lines 4 and 5, the lightning arrester 3 of the subscriber protector 1 will discharge,
The surge current is discharged to the ground via a grounding wire 14 and a grounding resistor 17. However, since this contact jII11 resistor 17 is present, the potential of the ground near the resistor J7 rises due to the voltage drop caused by this resistor. i.e. jit TJi
Despite the discharge of the device 3, the communication lines 4 and 5 are
Well, it's not bad enough. On the other hand, the power line 11
．． Normally, one wire of 12 is grounded in the pole-mounted transformer 13 through a grounding wire 16, grounding, and a resistor 19, and the resistance value μ of this resistor 19 is 1.
Compared to 7, there are many lower threats. The housing 10 of the telephone circuit 8 is also grounded via the grounding wire 15 and the grounding resistor 18.
There may be cases where

In such a case, the ground potential near the resistor 17 is high and the ground potential near the resistors 18 and 19 is low, so the communication I%!
4, 5 and the telephone housing 100, and if the line termination device 6 does not have sufficient pressure resistance, an insulation rupture occurs, and a surge current flows through the communication line 5. → Line termination device 6 → Communication line 5' → Telephone housing 10 → Ground wire 15-
1 earthing resistance 18→dog ground, and the line termination device 6 is destroyed. Or, in addition, 1 of the lightning 1 talker circuit 8 and the power transformer 9
Next, spar between the secondary [2 power wire 12, ground wire 16,
A surge current flows to the ground through the earth resistance] 9,
Destroy the machine circuit 8 and power transformer 9.

FIG. 2 shows a circuit configuration in which a lightning transformer 21 with high insulation performance is connected between the telephone circuit 8 and the lightning and wiring lines 11 and 12 in order to improve the voltage resistance between them.

In this case, the installation of the lightning transformer 21 increases the size of the device as a whole, increases the cost, and requires additional power consumption in the power transformer 21. In addition, in this method, the communication line 4 in FIG.
, 5 → line termination device 6 → communication line 4, 5 → telephone housing 10
→ Grounding wire 15 → Grounding resistor 18 → Earth cannot be expected to have a high withstand voltage, so it is not useful for preventing damage to the line termination W6.

The present invention has been made in view of the above-mentioned conventional technical circumstances, and therefore, an object of the present invention is to provide a housing in which a communication device that is supplied with commercial power via a power line is housed. It is effective against buttons that enter from communication lines or power lines, increases in size, increases in price, and dissipates 11 electric power.
In order to avoid causing problems such as 111 I31.-jZ), - J KI A
Z).

The configuration of the present invention is supplied with a commercial "111" power source via at least one pair of power supplies/11♀, and is connected to a commercial "111" source via at least a pair of communication lines. Between the two above-mentioned cities, il'; i Kg!, which are housed in the body and in the frk body, there is a small body;
Connect the two 111 river limit circuits in a column 11, and connect the two 1's with the same number 1'') ``1'1ir< , v+
Between 'y, two voltage limiting circuits are connected in series, and the two 111 circuits connected in series between the Vt power supply lines are
: Connect between the intermediate point of the voltage limiting circuit and the intermediate point of the two voltage limiting circuits connected in series between the communication line, and connect at least one point between the connection point of (and the housing) The box is connected via a pressure limiting circuit, and by grounding the box, it is possible to prevent vertical
The present invention is characterized in that the communication device is arranged to visit the island.

The present invention will now be described in detail with reference to the drawings.

Figure 3 shows an example of the embroidery of the present invention (starting with a circuit diagram) 7)
.

In the figure, 25 to 28, 30, 32, 33. :35
゜36 to 39 are bidirectional voltage limiting elements, respectively, 29゜34 are resistors, 31.401;
source circuit (in Figures 1 and 2, !l' 1,
1Iil path 8). Also, tIf
fi pressure limiting elements 32, 33 and 36,370
Let's call it medium X (1 + 1 drain each).

2.11 (High voltage appears on the signal lines 4 and 5. Despite the operation of the lightning device 3, the communication Lines 4, 5, 1[
7. If the river does not flow down, it operates to protect the line termination device 6 and the telephone circuit 8 from fraud.

The voltage limiting elements 25 to 28 provided in the housing 7 are elements such as a zinc oxide varistor, a bidirectional voltage regulator diode, and a discharge type lightning arrester. First of all, regarding the bulk of the line termination device 6, between the communication lines 4.5 and 4/, 5/, any two of the four voltage limiting elements 25, 26 and 27. Since it is clamped by the sum of the limit voltages, the line terminal side @6 is protected by designing a vertical surge withstand voltage on this clamp pressure plate.2. .

For example, voltage limiting elements 25 and 28 are used between IT lines 4 and 5', voltage limiting elements 26 and 27 are used between communication lines 5 and 4', and voltage limiting is applied between communication lines 4 and 5. Element 2
5 and 26 and between communication lines 4' and 5 by voltage limiting elements 27 and 28, respectively.

Although the resistor 29 and the voltage limiting element 30 are not directly related to the present invention, they constitute a circuit for absorbing a surge between the communication lines 4 and 5 (a surge between the lines). The voltage limiting element 30 is designed to operate at a voltage lower than the sum of the operating voltages of the voltage limiting elements 25 and 26. Communication line 4.
5), the voltage limiting element 30 operates and clamps the line voltage. When a voltage drop occurs across the resistor 29 due to a surge current, the sum of this voltage drop and the clamp voltage of the voltage limiting element 30 is applied to the voltage limiting element 2.
Since it is added to the series circuit of 5 and 26, this series circuit operates and clamps the voltage.

Next, between the communication lines 4 and 5 and the telephone group 10, the communication line 4'
, 5' and the power line 11.12 respectively, the telephone outlet T1 road 8, the city source circuit 9',
I will now explain the protection of the power transformer 9, etc. The frost and ratio limiting elements 32, 33, and 36 to 39 are comb elements each consisting of a zinc oxide varistor, a bidirectional constant voltage dimer, and a radial arrester. Communication core 4.5 and power line 1, i
, 12 are voltage limiting elements 32, 33, etc. 36°37
It is limited by the clamp voltage of a series circuit consisting of a combination of two of them.

Specifically, between the communication line 4 and the power line 11, there are voltage limiting elements 32 and 36, and between the communication line 4' and the power line 12, there are
Two voltage limiting elements each: voltage limiting elements 32 and 37, voltage limiting elements 33 and 36 between communication line 5 and power line 11, and voltage limiting elements 33 and 37 between communication line 5' and power line 12. It is clamped by the clamp voltage of a series circuit consisting of.

Therefore, the molecule between the power transformer 901st and 2nd order! If the voltage is set higher than this clamp voltage, telephone circuit 8, TJ,
Each prefecture FP 4-, such as the source circuit 9', is protected against surges during this period. Further, between the housing 10 and the communication line 4.5 and the power line 11.12, there are two voltage limiting elements 32, 33 and 39, and two voltage limiting elements 36, 37 and 39. Voltage is limited in a series circuit.

To be specific, 1. Between the wire 4' and the housing 10 (more specifically, the ground wire 15 connected to the pipe body 1 (l Vc knee i) J), the voltage 1 to 1'' is connected to the limiting elements 32 and 39, and the communication line 5. ' and the housing 10 are provided with voltage limiting elements 33 and 39,
Voltage limiting elements 36 and 39 are connected between the power line 11 and the housing 10.
, voltage limiting elements 37 and 3 are connected between the power supply line 12 and the housing 10.
9, each of which is clamped by a clamp voltage of a series circuit consisting of two voltage limiting elements.

The features of this embodiment include communication lines (4, 5), power lines (11,
12) The distance between any two combinations of the casings (grounding wire 15) is limited by a clamp voltage of a series circuit consisting of two voltage limiting elements.

By adopting such a configuration, it is possible to make the limit voltages between them all the same. Furthermore, it is necessary to make the limit voltages between any two of the 5K, the communication line 9g, the original line, and the casing the same level, as explained in the following sheet.

According to regulations such as JIS-C-702, the dielectric strength JE between the casing and the circuit section within the casing is set to be IKV or higher.

If this regulation is also observed in the communication terminal, the communication line (4'
, 5') and any two of the power supply wires (11, 12) and one of the housing 10 (more specifically, the ground wire 15) 5B).
A breakdown voltage of V or higher is required.

When attempting to satisfy the above-mentioned regulations by using a conventional circuit as shown in FIG. 4, instead of using the circuit shown in FIG. ' and housing 1
0 (grounding wire 15) is more than iKV, the operating voltage of the voltage limiting element 32 or 33 needs to be about 1,500V or more in direct current.

The same applies to the connection between the power supply line 11 or 12 and the casing 10.The operating voltage of the TrL pressure limiter 36 or 37 must also be set to about 1.500V or higher in direct current. As a result, there are 111 direct lines between the communication line 4 and the power line 11 or 120, and between the communication line 5' and the power line 11:t or 120, consisting of two L1 and pressure limiting elements.
The voltage for one operation is 37<V or higher.

Roughly speaking, each 7[r5 pressure limiting element has t, [surge due to operating resistance], the flow is ll:1', and the maximum is 1tt.
l) The limiting voltage increases by a factor of 15-2. The limiting lightning current as an outer pleural circuit can rise up to 45-6 KV.

Therefore, in the configuration of the protection circuit from 11r shown in FIG. 4, the power transformer 9. It is essential to increase the withstand voltage of the power supply circuit 9'. In order to make the power supply circuit high withstand voltage, V, l
However, it is necessary to take measures such as making the component parts high withstand voltage and widening the wiring spacing, but these devices need to be made smaller and more economical.

This is contrary to the goal of reducing IR power consumption and is not desirable.

On the other hand, regarding this point, in one embodiment of the present invention shown in FIG. 3, any two of the communication line, power supply line, and casing are protected by a series circuit of two voltage limiting elements, respectively. For example, if the operating voltage of each of these voltage limiting elements is set to a voltage slightly exceeding 700 Ω, any two of the communication lines, electrical wiring, and fa body can be The operating voltage between the two is slightly over 1,400V. Even if we take into account the increase in voltage due to the operating resistance, the operation between each '+'l, pressure C' will be approximately 3,000 V, and each interval will be clamped by such πj,
Therefore, the high durability required for the 9 transformer 9 H'tlf, d9 circuit 9' (not shown in FIG. 4) is reduced to about half that of the case where one round circuit is used. This T,i
The printing pressure of lu can be easily reduced to 1' even using conventional parts and wiring methods.
1.

The difference between the circuits in Figures 3 and 4 +71 is the voltage! f
Regarding the presence or absence of the ill limiter 39, the usefulness of this limiter 39 is recognized from the above explanation. They must have the same operating voltage, for example, 1.500 V for those connected to the communication line, 900 V for those connected to the power supply line VC, and 900 V for those connected to the housing. . In this case, between the communication line and the power supply line9, the communication line and the housing operate at approximately 1,400V, and the power supply line and the housing operate at approximately 1,800V.

FIG. 5 is a circuit diagram showing another embodiment of the present invention. The difference between the circuit configuration shown in the same figure and the one shown in FIG. 3 is that in FIG. i(6, 5th
In the figure, the telephone circuit 8 and the telephone circuit 8 are housed in the same housing 10.

In the case of digital direct-talk devices, there are models in which the telephone main body and the circular termination device δ are separated, and models in which they are integrated. shi, there is no special meaning υj, other than that.

FIG. 6 is a circuit diagram showing still another embodiment of the present invention.

The embodiment shown in the figure has two pairs of communication lines (4°5 and 4814
9)) An example is shown in which the Tn'le communication device g145 is housed in the casing 10 and protected.

Between the communication lines 48 and 49, voltage limiting elements 46 and 47 are connected in series, as in the case of the communication lines 4 and 5, and the intermediate point is connected to the housing 10 and the ground line via the voltage limiter 39. 15 has been successfully connected. There is no need to explain the operation again. FIG. 7 is a circuit diagram showing still another embodiment of the present invention. The embodiment shown in the same figure uses two pairs of communication lines like the embodiment shown in Fig. 6, and in order to collect and process surges entering each communication line in one place, It is characterized by its ability to absorb surges efficiently.

In FIG. 7, 50 and 51 are diode bridges, and 52 to 54 are voltage limiting elements or voltage limiting circuits, respectively.

Communication line? ii. The case of absorbing surge between source lines will be explained. When the communication line 4' is positive, the power line 11 is connected to the upper left diode in the diode bridge 50, through the voltage limiting element 53, and further through the voltage limiting element 36.
or the power supply line 12 via the voltage limiting element 37.
It is clamped by a series circuit of two voltage limiting elements on the path (■→■') leading to . The same applies to other communication lines.

The case of absorbing the surge between the communication line and the case is as follows. That is, when the communication line 4 is positive, the two voltages in the upper left diode in the diode bridge 50 and the path (■→■) leading to the housing 10 (ground wire 15) via the voltage limiting element 53.39 It is shifted by a series circuit of limiting elements. The same applies to other communication lines.

Surge absorption between the casing 10 (grounding line 15) and the power supply line 11 or 12 is performed by clamping by a series circuit of two voltage limiting elements 39 and 36 or 37.

In this embodiment, when the series circuit consisting of two voltage limiting elements as described above operates, the potentials of all the communication lines become equal, so that surges between the communication lines are unlikely to occur. Furthermore, if a lateral surge appears between the communication lines before the series circuit consisting of two voltage limiting elements operates, the voltage limiting circuit 5
2 can be easily absorbed.

For example, the lateral surge between communication lines 4 and 48 is ■
As shown by the dashed line path from ■, the diode bridge 5
The communication line 48 is connected through the upper left diode of 0, the voltage limiting circuit 52, and the upper right diode of the dimate bridge 51.
is absorbed by the clamp in the series circuit leading to . As the voltage limiting circuit 52, in addition to single elements such as a varistor, a constant voltage diode, and a discharge type escape tube, a series circuit of a varistor and a silice can also be used. By using a capacitor in the gate circuit, it is possible to ignite only for high-voltage, fast-rising waveforms such as surges. The circuit can clamp the compressor at a lower η1 voltage than the voltage limiting element alone.

55 to 58 are resistors assumed to be inserted into communication lines 4.5 and 48.49. These 1 [(resistors) are the same when the surge current withstand capacity of the constant voltage limiting circuit 52 is small, and ('-
1. It can be used when it is necessary to further improve lateral surge absorption and 11. Overheating often occurs due to variations in discharge of 3.3 A% in discharge type lightning arresters in subscriber protectors.

In other words, for j... between a discharged lightning arrester (for example, 3A) and an undischarged N arrester (for example, 3), ■'→■→52−■
A high voltage is generated through the path →■“.

This high voltage is absorbed by the Tj, 1 pressure control circuit 52. If the resistors 55 to 5) 3 are not inserted, the voltage applied to the surge arrester 3 that is not discharging is due to only the clamp pressure of the voltage limiting circuit 52, so even if the surge frost 5 voltage rises, this surge arrester 3 may not discharge.

1 In this case, a large current will flow through the voltage limiting circuit 52, so this voltage limiting circuit 52 is required to have a large resistance to 1d, and also has characteristics that prevent the pressure from rising due to surge current. is necessary. Therefore, the requirements for the voltage limiting circuit 52 become stricter.

However, when resistors 55 to 58 are inserted, when the voltage limiting circuit 52 operates and a surge or current flows, the voltage drop due to these resistors 55 and 57 and the clamp voltage of the voltage limiting circuit 52 are discharged. Since the current is applied to the outer arrester 3, this arrester 3 is forced to discharge. If all the M avoiders are discharged in this way, there will be no lateral surge.

The embodiment shown in FIG. 7 has the advantage of high processing efficiency because when there are many pairs of communication lines, the Σ surge entering each communication line is collected in one place by a diode bridge and processed. C-L or the diode bridge itself 4.1
-1 In figure 1, one consists of four diodes and the other consists of 1. However, since only one component is used, the number of components is reduced compared to the case where two voltage limiting elements are used for each pair of communication lines, as shown in FIG. There is also the advantage that it can be reduced.

21''S8 Figure F is a circuit diagram showing an embodiment in which the present invention is applied to a public telephone line.
Each 6 is a ballista, and next to it is the number V in ).
``operating voltage, ``1''1 is the telephone Ji', L path, T2 call control circuit, and P is the power supply circuit. Telephone circuit T1 and >
IV] During the talk control circuit j'15T20, the primary and secondary circuits of the power supply circuit P are spatially separated, and the total separation voltage is 2 to 3 KV or more. Some parts of the power supply circuit () are still attached to the housing 10 through an insulating layer such as mylar film to prevent temperature rise due to heat generation. The breakdown voltage of this part is about 2 to 3 KV. Further, E is a grounding wire of the telephone circuit T1.

Public telephones are required to have extremely high reliability because they pay charges instantly on the spot when they are used. This invention is the nt
We will discuss below that it is also effective in preventing movement.

In Fig. 8, the equipment shown in 7]e is the public telephone 1lITi machine 1.
00 V commercial '1; Since L source is used, insulation standard 5i4 specified by JIS VC, ii U circuit P To II
Body 10 and rlACl, 1 elbow pressure of 0OOV or more is required. The varistor circuit (V6 and
The operating voltage of the series circuit of 3 (ma=';v, fJ series circuit of JVFI and V3) is 1.770V, so the tolerance is 10%.
1. ．． Even if the insulation is measured using the 0OOVAC power supply, the series circuit of the varistors will not operate, and there will be no problem with conducting the insulation test.

Once Leege enters, a surge current flows along the path shown by the two-dot chain line. At this time, between the communication line 5 and the housing 10, there is a series circuit of ■2 and v3, and between the communication line 5 and the power line 12, there is a series circuit of v2 and ■6, and as mentioned above, they are each clamped. That's right.

Next, let's talk about malfunctions. The main cause of malfunctions is that the voltages between the casing and the communication line and between the casing and the power supply line rise when a surge enters.

Therefore, it is desirable to limit the voltage during this period.

In particular, as mentioned above, some of the parts of the power source [11 path P] are attached to the housing 10, and these parts are easily affected by surges, so be sure to connect the power line and the housing. It is necessary to clamp at a low voltage during this period. This embodiment describes that this is possible.

FIG. 9 is a circuit diagram showing the ji' route shown by the two-dot chain line in FIG. The voltage between the casing 10 and the frost line 12, that is, the voltage between ■ and ■ is the clamp voltage of V6 minus the clamp voltage of V3. In the conventional circuit, since the gate 3 did not exist, the clamp voltage of v6 became the voltage between the casing and the power line. The effect of preventing malfunctions by reducing the clamp voltage between the casing and the power supply line in this embodiment in this manner was experimentally confirmed.

When this protection circuit is used for a device (public telephone) that malfunctions due to a surge of about 3KV with a conventional protection circuit, the voltage is 16KV.
It was confirmed that the system is extremely effective against the above surges without any malfunctions.

When implementing the present invention, if it is difficult to ground the casing, it is unavoidable to omit Q11, but even in that case, the same grounding effect may be obtained. In that case, it goes without saying that the present invention is effective.

J: sea urchin explained above, the present invention is 3i0. Between the I city line and the pipe body, between the electric line, Minamoto Chikane and the housing, between the communication line and the power line, connect the electric line 11E iii! This voltage control is done because it is clamped by a series circuit of two I limiters! ! (:, Nico's:till
l! By selecting a suitable combination of IM voltages, clamping the leege at a low ``II'' voltage violates the insulation test.

Therefore, the present invention is useful for protecting vertical racks of equipment such as electronic telephone terminals, which require insulation testing and are difficult to incinerate.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an example of a configuration in which a conventional technology has been applied to prevent lightning surges for a digital '1 story terminal.
1gl is a circuit diagram showing a conventional example constructed using a lightning protection transformer, FIG. 3 is a circuit diagram showing embodiments of the present invention, FIG. 4 is a circuit diagram showing a conventional vertical strip protection circuit, and 7 to 7 are circuit diagrams showing other embodiments of the present invention, and FIG.
The figure is a circuit diagram showing an implementation example 1j in which the present invention is applied to a public telephone set.
! 1) is a circuit diagram extracted and shown. Ladle number oil, light

Claims (1)

[Claims] J) In a housing containing a communication device which is supplied with a commercial type power source via at least one pair of power supply lines and which communicates via at least one pair of communication lines, a pair of two Between the power wires of the book (Is there a little bit of 7 pressure between the two spiders?'
Jl limiting circuits are connected in series, [n] at least two voltage limiting circuits are connected in series between the two communication lines forming a pair, and at least two voltage limiting circuits are connected in series between the IFi source lines. Connect between the midpoint of the two connected voltage limiting circuits and the midpoint of the two 1/2 ratio limiting circuits connected in series between the (f) lines, and connect the connecting point. and the housing through at least one voltage limiting circuit, and by grounding the housing, it is possible to prevent vertical surges entering through communication lines or power supply lines. A case grounding circuit for protecting a vertical column, characterized in that the communication device is protected against damage.