JPH0717235Y2 - Overvoltage protection element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an overvoltage protection device having a parallel connection structure of a discharge element and a voltage non-linear resistance element, and more particularly, to a discharge element and a voltage non-resistance element. By properly setting the operating voltage of the linear resistor element to the power supply voltage, if an electronic device is mistakenly connected to a power supply with a voltage exceeding the rating, this is protected from overvoltage and the electronic device is The present invention relates to an overvoltage protection element capable of absorbing surges of large and small sizes that try to enter the power supply when connected to a power supply.

[Prior Art] Conventionally, as this type of overvoltage protection element, an arrester formed by enclosing a discharge element in an airtight container, a varistor formed of a voltage non-linear resistance element, and the like have been widely known. It is used by being connected between a circuit of an electronic device and a power supply.

[Problems to be Solved by the Invention] When an arrester is used as the overvoltage protection element, the overvoltage applied when an electronic device is incorrectly connected to a power supply having a voltage exceeding the rating, or when connected to a power supply having a rated voltage. Large surges such as induced lightning that try to enter the equipment while it is in operation are absorbed by the arrester, but are small surges such as switch opening / closing surges, that is, the voltage is not so high and the pulse width is narrow. When a surge is applied,
Surge absorption becomes insufficient because the discharge element has a discharge delay time.

On the other hand, when a varistor is selected as the overvoltage protection element, small surges such as switch opening / closing surges in the above rated operating conditions are immediately eliminated because the varistor response speed is fast, but the above-mentioned power supply A large surge such as overvoltage or induced lightning for a relatively long time due to erroneous connection significantly deteriorates the characteristics of the varistor, and in extreme cases, the varistor may be destroyed.

The present invention has been devised in view of the above-mentioned points, and protects equipment from continuous overvoltage applied when an electronic equipment is erroneously connected to a power supply having a voltage higher than the rating, and is in a rated use state. Another object of the present invention is to realize an overvoltage protection element that absorbs surges of large and small sizes that try to enter an electronic device and that is not likely to be significantly degraded or destroyed due to surge absorption.

[Means for Solving the Problems] In order to achieve the above-mentioned object, an overvoltage protection device according to the present invention is an overvoltage protection device connected between a circuit of an electronic device and a power supply, and has a voltage non-linearity. At both ends of the resistor element, a pair of discharge electrodes are connected to form a discharge gap between the discharge electrodes, and the discharge gap and the discharge gas are housed in the same airtight container.
Therefore, a parallel connection structure is formed between the discharge element having the discharge gap and the voltage non-linear resistor element, and the operating voltage of the discharge element is added to the maximum value of the rated power supply voltage of the electronic device by a voltage fluctuation component. Higher than the above value, and lower than the maximum value of the power supply voltage higher than the rated power supply voltage above which the electronic device may be connected incorrectly, minus the voltage fluctuation, and the voltage nonlinear resistance The operating voltage of the body element,
It is set higher than the maximum value of the power supply voltage that may be erroneously connected, plus the voltage fluctuation.

[Operation] In the present invention, the operating voltage of the discharge element is set to be lower than the value of the maximum value of the power supply voltage that may cause incorrect connection minus the voltage fluctuation. When the electronic device is erroneously connected to a power supply exceeding its rating and the overvoltage is continuously applied, the discharge element operates reliably to prevent the continuous overvoltage from entering the circuit of the electronic device. In this case, the operating voltage of the voltage non-linear resistance element is set higher than the value of the maximum value of the power supply voltage that may cause erroneous connection, plus the voltage fluctuation. It does not operate, and therefore, there is no risk of deterioration or destruction of its characteristics due to continuous overvoltage.

On the other hand, when the electronic device is connected to the power supply of the rated voltage, the overvoltage protection element does not operate and the power supply to the device is continued. Also, small surges such as switch opening / closing noise are absorbed by the voltage non-linear resistance element. Furthermore, when a large surge such as inductive lightning is applied in this rated operating condition, the voltage non-linear resistance element operates first and then the discharge element operates to absorb surge due to the response speed. Be seen. In this case, since the voltage at which the voltage non-linear resistor element operates has already reached the discharge start voltage of the discharge element, the operation transition from the voltage non-linear resistor to the discharge element is immediately performed. Therefore, the operating time of the voltage non-linear resistance element is extremely short, and the characteristic deterioration of the resistance element hardly occurs.

Since the discharge element and the voltage non-linear resistance element are housed in the same airtight container filled with the discharge gas, the operation of the voltage non-linear resistance element generates an excited discharge in the discharge element, which is instantaneous. Since the transition to the main discharge occurs, the operating time of the discharge element becomes extremely short.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention.
FIG. 1 is a sectional view of an overvoltage protection element, and FIG. 2 is a circuit diagram in a state where the overvoltage protection element is connected to an electronic device.

In the figure, an overvoltage protection device 1 includes a pair of electrodes 2,2 made of a metal having good discharge characteristics such as Ni, Fe or alloys thereof, a sealing cap 4, from which lead wires 3,3 are drawn, It is connected to approximately the center of 4, and this is the discharge gap 5 between the electrodes 2 and 2.
The discharge element 6 is formed so as to face each other so that a voltage non-linear resistor element 7 made of a metal oxide such as ZnO or BaTiO ₃ is connected between the electrodes 2 and 2. The sealing caps 4 and 4 have a structure in which the peripheral portions of the sealing caps 4 and 4 are sealed to both ends of a cylindrical body 8 made of an insulating material such as ceramics or glass.

The cylindrical body 8 and the sealing caps 4 and 4 constitute an airtight container 9 in which a rare gas such as He, Ne, Ar or a discharge gas such as a nitrogen gas is sealed, and the discharge element 6 and The voltage non-linear resistor element 7 is integrated in a state of being connected in parallel, and is housed in the same airtight container 9.

The operating voltage Va of the discharge element 6 is higher than the maximum value of the rated power supply voltage of the electronic equipment to which the overvoltage protection element 1 is connected, plus the voltage fluctuation, and the electronic equipment may be erroneously connected. Is set lower than the maximum value of the power supply voltage minus the voltage fluctuation. For example, assuming that the rated power supply voltage is AC100 [V] of the commercial power supply, the power supply voltage that may cause incorrect connection is also AC200 [V], and the voltage fluctuation rate is 10%, the operating voltage Va of the discharge element 6 is , 156 [V]
It will be set in the range of <Va <253 [V].

Further, the operating voltage Vv of the voltage non-linear resistor element 7 is set higher than a value obtained by adding a voltage fluctuation amount to the maximum value of the power supply voltage at which the electronic device may be erroneously connected.
For example, in the same way as above, the power supply voltage that may cause incorrect connection is
Assuming that the voltage fluctuation rate is 10% at AC 200 [V], the operating voltage Vv of the voltage nonlinear resistor element 7 is set to 311 [V] <Vv. The operating voltage Va of the discharge element 6 and the operating voltage Vv of the voltage non-linear resistance element 7 should be set as small as possible within the above range, so that the sensitivity to the surge becomes better.

Thus, the overvoltage protection element 1 is provided between the circuit 31 of the electronic device and the power source (not shown), for example, as shown in FIG.
A conductor 31 that is connected to a power source for powering the equipment circuit 31
It is used by being connected between a and 32b. In this state,
In the case of incorrect connection to a power supply with a voltage higher than the rated voltage, or in the event of a large surge such as induced lightning, an overvoltage protection device 1
Operation causes a current to flow between conductors 32a and 32b,
It can be confirmed that the fuse 33 connected to 2a is melted and the connection is wrong and a large surge has entered. Since the overvoltage protection element 1 operates and a current flows between the conductors 32a and 32b due to a small surge that accompanies the opening and closing of the switch 34 connected to the conductor 32a, the fuse 33 is selected so as not to be blown by the above current. There is a need.

In the overvoltage protection element 1 of the present embodiment, the discharge element 6 and the voltage non-linear resistance element 7 are integrated, so that the mounting space for mounting the electronic equipment on the electronic device is small. Further, since the discharge element 6 and the voltage non-linear resistance element 7 are enclosed in the same airtight container 9, the operation of the voltage non-linear resistance element 7 produces an excited discharge in the discharge element 6 during operation. However, since this is instantaneously transferred to the main discharge, the operating time of the discharge element 6 becomes extremely short.

[Effects of the Invention] As described in detail above, the overvoltage protection device of the present invention has a discharge device and a voltage non-linear resistance device connected in parallel, and the operating voltage of each device is appropriately set in relation to the power supply voltage. As a result, large surges and continuous overvoltages due to incorrect power connections are mainly absorbed by the discharge element, and small surges are absorbed by the voltage non-linear resistor element. It can be protected for a long time, and it can withstand long-term use without the risk of element deterioration or destruction.

Further, by configuring the discharge element and the voltage non-linear resistance element to be housed in the same airtight container, the operation of the voltage non-linear resistance element generates an excited discharge in the discharge element, which is instantaneously Since the transition to discharge occurs, the operating time of the discharge element becomes extremely short.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention.
FIG. 1 is a sectional view, and FIG. 2 is a circuit diagram in a state of being connected to an electronic device. 1 ... overvoltage protection element, 2,2 ... electrode, 5 ... discharge gap, 6 ... discharge element, 7 ... voltage nonlinear resistor element, 9
...... Airtight container.

Claims (1)

[Scope of utility model registration request] 1. An overvoltage protection element connected between a circuit of an electronic device and a power supply, wherein a pair of discharge electrodes are connected to both ends of a voltage non-linear resistor element, and a discharge gap is provided between the discharge electrodes. To form a parallel connection structure of the discharge element having the discharge gap and the voltage non-linear resistor element, and storing the discharge gas in the same airtight container together with the discharge gas. , Which is higher than the maximum value of the rated power supply voltage of the electronic device plus the voltage fluctuation, and which is higher than the rated power supply voltage at which the electronic device may be erroneously connected. It is set lower than the value obtained by subtracting the fluctuation, and the operating voltage of the voltage non-linear resistor element is set higher than the value obtained by adding the voltage fluctuation to the maximum value of the power supply voltage that may be erroneously connected. Overvoltage protection element characterized by .