JP2021126024A - Protective device for led lighting fixture - Google Patents

Abstract

To provide a technology that achieves both protection in an event of a short circuit failure of an electric circuit inside an LED lighting fixture and protection against lightning surges.SOLUTION: The surge protective element circuit protects against relatively low surges such as induced lightning surges. Two types of fuses are used to achieve a dual purpose of protection in an event of damage to the surge protective element circuit and protection in an event of failure of a lighting control circuit.SELECTED DRAWING: Figure 1

Description

The present invention relates to a protective device for an LED lighting fixture that illuminates an illuminated portion such as a road surface by emitting light from an LED (light emitting diode).

Lighting fixtures installed outdoors, such as road lights and park lights, illuminate the road surface and the like with a light emitting unit that uses a lighting LED (light emitting diode) as a light source. Electronic components such as semiconductors are used in the lighting control unit (including the rectifying circuit and LED lighting control circuit) of the lighting LED, and the input voltage to the lighting equipment is to apply a predetermined voltage such as 100V or 200V. The luminaire is designed to operate normally.

In such a lighting fixture, when a lightning surge called an induced lightning surge occurs in the power line of the lighting fixture due to the induction action by a lightning strike, the lightning surge causes the lighting control unit (rectifier circuit and LED lighting control circuit) of the lighting LED. (Including) may be damaged, and this is prevented by a lightning surge protection device.

As one of the lightning surge protection devices, there is one in which a surge absorber such as a varistor is used between two power lines of an AC power input circuit which is an external power source for a lighting fixture (Patent Document 1).
Patent Document 1 has a surge absorber 51 and a plurality of varistor 52 as a lightning surge protection circuit 50, one end of the surge absorber 51 is connected to a ground wire G, and one end of the plurality of varistor 52 is a surge absorber. The other end of the varistor 52 is connected to the other end of the 51, and the other end of the varistor 52 is connected to each of the plurality of power supply lines 11.
When the voltage to ground between the power supply line 11 and the ground wire G exceeds a predetermined overvoltage threshold value, the protection circuit 50 changes from a non-conducting state to a conductive state, short-circuiting the power supply line 11 and the ground wire G. This protects the control power supply of the LED and the LED.

Further, as another surge absorber circuit 50, fuses F1 and F2 are connected to the two wires of the active side wiring and the inactive side wiring of the AC power supply E which is an external power supply, respectively, and the fuses F1 and F2 are downstream (output). Varistors Z1 and Z2 as surge protection elements are connected in series on the side), and intermediate terminals of these varistors Z1 and Z2 are ground-connected via varistor Z3 as surge protection elements (Patent Document 2).
The protection circuit 50 of Patent Document 2 is applied between the varistors Z1 and Z2, between the varistors Z1 and Z3, and between the varistors Z2 and Z3 through the fuse F1 or the fuse F2 when the induced lightning is applied to the AC power supply E. These varistor Z1, Z2, and Z3 limit the surge to a voltage equal to or less than a predetermined value, and protect the power supply board and the light source module.
When the surge energy exceeds the withstand voltage of the varistor Z1, Z2, Z3, the fuses F1 and F2 are blown to protect the power supply board and the light source module.

Patent Document 1 provides only one-step protection by conduction of a lightning surge protection circuit 50 composed of a surge absorber 51 and a plurality of varistor 52. In Patent Document 2, the surge is set to a predetermined value by the varistor Z1, Z2, and Z3. In addition to the protection limited to the following voltage, the protection is thicker than that of Patent Document 1 in that two stages of protection can be obtained by blowing the fuses F1 and F2.

Japanese Unexamined Patent Publication No. 2019-47542 Japanese Unexamined Patent Publication No. 2018-133234

In Pat. Protect the LED. Further, when a current exceeding the rated current flows, the fuse blows to protect the control power supply of the LED and the LED.

As for the protection of the lighting equipment, not only the protection against lightning surge as in Patent Document 1 and Patent Document 2, but also the short-circuit current flows due to the failure of the lighting control unit (including the rectifying circuit and the LED lighting control circuit) of the lighting LED. It also needs protection in case of emergency.

In view of these points, the present invention provides a technique for achieving both protection against a short-circuit failure of an electric circuit inside a luminaire and protection against a lightning surge.

Therefore, according to the present invention, the surge protection element circuit can achieve protection against a relatively low surge such as an induced lightning surge, and also protects the surge protection element circuit when it is damaged and when the lighting control unit fails. Two types of fuses are provided according to one purpose.

The first invention is
The input circuit 3 that supplies the DC power obtained by converting the AC power supplied from the AC power source 2 which is an external power source by the AC 2-wires L1 and L2 by the rectifying circuit 6 to the lighting control circuit 4 of the lighting LED 7 is On the upstream side (input side) of the surge protection element circuit 9A that switches from the non-conducting state to the conductive state at a predetermined operating voltage with respect to the surge applied to the AC 2-wires L1 and L2, and the surge protection element circuit 9A. The first fuses F1 and F2, which are arranged on the AC 2-wires L1 and L2 and do not blow in the normal operating state of the surge protection element circuit 9A against the surge, but blow due to a short-circuit current at the time of failure of the surge protection element circuit 9A. It is arranged on at least one of the AC 2-wires L1 and L2 on the downstream side (output side) of the surge protection element circuit 9A, and does not blow in the normal operating state of the lighting control circuit 4, and is not blown on the downstream side of the surge protection element circuit 9A (the surge protection element circuit 9A). The first fuse F1 is provided with a second fuse F3 having an appropriate capacity that can be safely blown due to an increase in current or a short-circuit current when a component fails in the circuit on the output side), and the value of the blown current that the second fuse F3 blows is higher than that of the blown current value. , The fusing current value at which F2 is fused is set to be larger.

The second invention is
The input circuit 3 that supplies the DC power obtained by converting the AC power supplied from the AC power source 2 which is an external power source by the AC 2-wires L1 and L2 by the rectifying circuit 6 to the lighting control circuit 4 of the lighting LED 7 is On the upstream side (input side) of the surge protection element circuit 9A that switches from the non-conducting state to the conductive state at a predetermined operating voltage with respect to the surge applied to the AC 2-wires L1 and L2, and the surge protection element circuit 9A. The first fuses F1 and F2, which are arranged on the AC 2-wires L1 and L2 and do not blow in the normal operating state of the surge protection element circuit 9A against the surge, but blow due to a short-circuit current at the time of failure of the surge protection element circuit 9A. The first fuses F1 and F2 and the surge protection element circuit 9A are arranged on at least one of the AC 2-wires L1 and L2 on the downstream side (output side), and are not blown in the normal operating state of the lighting control circuit 4 and the surge. A second fuse F3 having an appropriate capacity that blows due to an increase in current or a short-circuit current when a component fails in the circuit on the downstream side (output side) of the protective element circuit 9A is provided, and the value of the blow current that the second fuse F3 blows is higher than that of the second fuse F3. Also, the fusing current value at which the first fuses F1 and F2 are blown is set to be larger.
The surge protection element circuit 9A includes a first surge protection element Z1 and a second surge protection element Z2 having a first operating voltage connected in series over the AC two wires L1 and L2, and the first surge protection element Z1 and the first surge protection element circuit 9A. The intermediate portion of the two surge protection elements Z2 is connected to the ground line via the third surge protection element Z3.

In the present invention, the surge protection element circuit 9A can achieve protection against a relatively low surge such as an induced lightning surge, protection at the time of failure of the surge protection element circuit 9A, and failure of the lighting control unit of the lighting LED 7. The feature is that the fuses are separated according to the two purposes of protection.
Therefore, the first fuses F1 and F2 have a circuit configuration for the purpose of a dedicated fuse for protection when the surge protection element circuit 9A is damaged, and the second fuse F3 is a part such as an inverter circuit of the lighting control circuit 4. It is suitable for protecting LED lighting fixtures that have achieved the above two purposes by forming a circuit configuration for the purpose of a dedicated fuse for protection in the event of a failure.

The first surge protection element Z1, the second surge protection element Z2, and the third surge protection element Z3 have a protection circuit configuration corresponding to all of the AC 2 wires and the ground line of the power supply circuit. Further, the first fuses F1 and F2 are connected to the AC 2-wires L1 and L2, respectively. As a result, it is possible to deal with lightning surges applied to either AC 2-wire L1 or L2 when viewed from the ground line, and it is also possible to deal with anti-aircraft discharge from the ground (ground surface or snow cover) toward the sky. Therefore, stable protection against lightning surges is achieved.

It is a figure which shows the circuit structure of the lighting device of the LED lighting fixture which concerns on this invention.

The protection device for the LED lighting fixture according to the present invention is
The input circuit 3 that supplies the DC power obtained by converting the AC power supplied from the AC power source 2 which is an external power source by the AC 2-wires L1 and L2 by the rectifying circuit 6 to the lighting control circuit 4 of the lighting LED 7 is On the upstream side (input side) of the surge protection element circuit 9A that switches from the non-conducting state to the conductive state at a predetermined operating voltage with respect to the surge applied to the AC 2-wires L1 and L2, and the surge protection element circuit 9A. First fuses F1 and F2 arranged on the AC 2-wires L1 and L2 and not blown in the normal operating state of the surge protection element circuit 9A against the surge but blown by a short-circuit current at the time of failure of the surge protection element circuit 9A. It is arranged on at least one of the AC 2-wires L1 and L2 on the downstream side (output side) of the surge protection element circuit 9A, and does not melt in the normal operating state of the lighting control circuit 4, and is not blown on the downstream side of the surge protection element circuit 9A (the surge protection element circuit 9A). The second fuse F3 has an appropriate capacity to be blown due to an increase in current or a short-circuit current when a component fails in the circuit on the output side), and the first fuses F1 and F2 are blown more than the blowing current value at which the second fuse F3 is blown. The fusing current value is set to be larger,
The surge protection element circuit 9A includes a first surge protection element Z1 and a second surge protection element Z2 having a first operating voltage connected in series over the AC two wires L1 and L2, and the first surge protection element Z1 and the first surge protection element circuit 9A. The intermediate portion of the two surge protection elements Z2 is connected to the ground line via the third surge protection element Z3.
Hereinafter, details of the embodiment of the present invention will be described with reference to the drawings.

One form of the LED lighting fixture LK according to the present invention is, for example, as shown in Japanese Patent Application Laid-Open No. 2018-0469694 according to the application of the present applicant, which is provided with an attachment portion to a support or the like at the rear portion and emits light for illumination inside. An LED as an element, a power supply unit (input circuit) that supplies power for the light emitting element, and an optical sensor arranged so as to detect the illuminance due to the light emission of the light emitting element and the illuminance due to the external light around the lighting fixture LK. It is a well-known form that includes a control unit (lighting control circuit) that controls lighting and extinguishing of the light emitting element based on the detected illuminance, and constitutes a lighting device with these.

FIG. 1 shows the circuit configuration of the lighting device 1 of the LED lighting fixture LK according to the present invention.
The lighting device 1 is supplied with power from a lighting control circuit 4, a light emitting unit 5 composed of a series circuit of an illumination LED 7 as a light emitting element, and an AC power source 2 which is an external power source by two AC lines L1 and L2. It includes an input circuit 3 that supplies DC power obtained by converting AC power by the rectifying circuit 6 to the lighting control circuit 4 of the lighting LED 7.

The input circuit 3 includes a surge protection element circuit 9A that switches from a non-conducting state to a conductive state at a predetermined operating voltage with respect to a surge applied to the AC 2-wires L1 and L2, and an upstream side of the surge protection element circuit 9A. A first fuse that is arranged on the AC 2-wires L1 and L2 on the (input side) and does not blow under the normal operating state of the surge protection element circuit 9A against the surge but blows due to a short-circuit current at the time of failure of the surge protection element circuit 9A. The surge protection element circuit is arranged on at least one of the AC 2-wires L1 and L2 on the downstream side (output side) of F1 and F2 and the surge protection element circuit 9A, and does not melt in the normal operation state of the lighting control circuit 4. A second fuse F3 having an appropriate capacity that blows due to a current increase or a short-circuit current when a component fails in the circuit on the downstream side (output side) of 9A is provided.
The second fuse F3 may be connected to both the AC 2-wires L1 and L2, but from the viewpoint of operation, at least one of the AC 2-wires L1 and L2 may be connected so as to be blown.

The fusing current value at which the first fuses F1 and F2 are blown is larger than the fusing current value at which the second fuse F3 is blown. The surge protection element circuit 9A includes a first surge protection element Z1 and a second surge protection element Z2 having a first operating voltage connected in series over the AC two wires L1 and L2, and an intermediate portion between the surge protection elements Z1 and Z2. Is connected to the ground line L3 via the third surge protection element Z3.

The input circuit 3 includes a second surge protection circuit 10 on the downstream side (output side) of the second fuse F3, a rectifier circuit 6 that converts alternating current into direct current, and a third surge protection circuit 11. C1 and C2 are capacitors, and R1 and R2 are reactors, which have the effects of reducing noise and improving the power factor of the lighting device 1.

The first surge protection circuit 9 is connected in series to the first fuses F1 and F2 connected to the AC two wires L1 and L2, respectively, and to the AC two wires on the downstream side (output side) of the first fuses F1 and F2. The first surge protection element Z1 and the second surge protection element Z2, and the intermediate portion which is the connection line between the surge protection elements Z1 and Z2 are connected to the metal body of the lighting fixture LK via the third surge protection element Z3. The metal body is connected to the ground line L3.

The first surge protection element Z1 and the second surge protection element Z2 are composed of, for example, a varistor, and are in a non-conducting (high impedance state) to a conductive state (hereinafter referred to as a first operating voltage) at an equivalent predetermined operating voltage (hereinafter referred to as a first operating voltage). It operates to switch to the low impedance state).
The third surge protection element Z3 is composed of, for example, an arrester, and has a predetermined operating voltage (hereinafter referred to as a second operating voltage) higher than the first operating voltage, from a non-conducting (high impedance state) to a conductive state (low impedance state). ) To switch to.
When the voltage of at least one of the AC 2-wires L1 and L2 rises due to the surge applied by the first surge protection element Z1, the second surge protection element Z2, and the third surge protection element Z3, the voltage is not set to a predetermined operating voltage. It constitutes a first surge protection element circuit 9A that switches from a conductive state to a conductive state.

The first surge protection circuit 9, the second fuse F3, and the second surge protection circuit 10 are collectively referred to as a surge protection device 8.
The second surge protection circuit 10 is a predetermined operating voltage (hereinafter referred to as a third operating voltage) over the AC 2-wires L1 and L2 on the downstream side (output side) of the first surge protection circuit 9 and the second fuse F3. The fourth surge protection element Z4 that switches from the non-conducting state to the conducting state is provided. The fourth surge protection element Z4 constitutes a second surge protection element circuit 10A that switches from a non-conducting state to a conductive state at a predetermined operating voltage higher than the operating voltage of the first surge protection element circuit 9A.
The second surge protection circuit 10 may be referred to including the second surge protection element circuit 10A and the second fuse F3.

The third operating voltage is set higher than the first operating voltage and the second operating voltage. As a result, the operating voltage of the first surge protection circuit 9 is set lower than the operating voltage of the second surge protection circuit 10, and in the embodiment, the first surge is set with respect to the operating voltage of the second surge protection circuit 10. The operating voltage of the protection circuit 9 is set to about half.

Further, the fusing current value of the first fuse F1 and the fusing current value of the first fuse F2 are set to be the same, and the fusing current value is such that the first fuses F1 and F2 are blown at a surge current as low as induced lightning. It is set to a very high constant, and the surge in that case protects the circuit of the lighting device 1 by the continuity of the surge protection elements Z1, Z2, and Z3 of the corresponding first surge protection element circuit 9A.
In order to ensure such an operation, the fusing current value at which the first fuses F1 and F2 are blown is set higher (larger) than the fusing current value at which the second fuse F3 is blown. In the embodiment, the fusing current values of the first fuses F1 and F2 are set to be several times the fusing current values of the second fuse F3, and the LED lighting fixture of one embodiment is about 1.5 to 2 times. Good results have been obtained with the setting of.

As a result, in response to the induced lightning surge that normally occurs during a lightning strike, that is, the induced lightning surge that is applied to the AC 2-wires L1 and L2 and passes through the first fuse F1 and / or F2, the first between the AC 2-wires L1 and L2. The surge energy is absorbed by the conduction operation of the surge protection element Z1 and the second surge protection element Z2, and the circuit of the lighting device 1 is protected. Further, between the AC 2-wire L1 and the ground line L3, surge energy is absorbed by the conduction operation of the first surge protection element Z1 and the third surge protection element Z3, and the circuit of the lighting device 1 is protected. Further, between the AC 2-wire L2 and the ground line L3, surge energy is absorbed by the conduction operation of the second surge protection element Z2 and the third surge protection element Z3, and the circuit of the lighting device 1 is protected.

On the other hand, the first surge protection element Z1, the second surge protection element Z2, and the third surge protection element Z3 have the first surge protection element Z1 and the second surge protection element Z2 when a surge exceeding the energy withstand capacity is applied. When the third surge protection element Z3 fails in a short circuit, the fuse F1 and / or F2 are blown by the short circuit current at that time, so that the surge input path is cut off and the circuit of the lighting device 1 is protected.
As described above, when the first surge protection element Z1, the second surge protection element Z2 and the third surge protection element Z3 are short-circuited, or the fuses F1 and / or F2 are blown, they are replaced.

In order to protect the circuit on the downstream side (output side) of the surge protection device 8 when a surge is applied or when the circuit is short-circuited, each of the above operating voltage values and fusing current values is set downstream of the surge protection device 8. Considering the withstand voltage and withstand current of the circuit on the side (output side), set it lower than that.
That is, in the normal state where no surge is applied, the circuit on the downstream side (output side) of the first surge protection circuit 9, that is, the lighting control unit (including the rectifier circuit 6 and the lighting control circuit 4) of the lighting LED 7 is damaged. The second protective fuse F3 is set so as not to blow if it does not short-circuit. Therefore, the withstand voltage of each component of the lighting control unit of the illumination LED 7 is set higher than the operating voltage of the first surge protection element Z1, the second surge protection element Z2, and the third surge protection element Z3, so that the first surge The fact that the protection element Z1, the second surge protection element Z2, and the third surge protection element Z3 do not conduct means that a surge lower than the operating voltage is applied. In this case, the circuit of the illumination LED 7 is Since the first fuse F1, F2, and the second protective fuse F3 are not blown as a result without being damaged, the lighting device 1 can maintain a stable operation.

In this way, the first fuses F1 and F2 guarantee that the surge protection element of the first surge protection element circuit 9A operates normally, and when the surge protection element of the first surge protection element circuit 9A is short-circuited due to a failure. Protects the electric circuit inside the LED lighting fixture by blowing due to the short-circuit current at that time.
Further, the second protective fuse F3 is set to a fusing current value of an appropriate capacity so as to be blown by a current increase or a short-circuit current at the time of failure of a component generated in the circuit on the downstream side (output side) of the surge protection element circuit 9A. There is.
Therefore, the normal operation of the circuit on the downstream side (output side) of the surge protection element circuit 9A is guaranteed, and when the circuit on the downstream side (output side) of the surge protection element circuit 9A fails and the current increases, the first 2 The electric circuit inside the LED lighting fixture is protected by blowing the protective fuse F3, and the lighting device 1 is protected.
Further, when an abnormally high voltage is generated in the input circuit 3 by the capacitors C1 and C2 and the reactors R1 and R2, the electrical circuit inside the LED luminaire is protected by the continuity of the surge protection element Z4.

If the first surge protection element circuit 9A does not operate against a surge, it is protected by the second surge protection circuit 10. That is, the first surge protection element Z1, the second surge protection element Z2, and the third surge protection element Z3, which should operate in a conductive state against a relatively high lightning surge applied to the AC two wires L1 and L2, are in a conductive state. If it is not switched to, the surge energy is absorbed by the conduction operation of the fourth surge protection element Z4 against the lightning surge applied to the AC 2-wires L1 and L2 through the fuse F3, and the circuit of the lighting device 1 is protected. NS. On the other hand, when a surge exceeding the energy withstand capacity is applied, the fourth surge protection element Z4 is short-circuited and the fuse F3 is blown, so that the surge input path is cut off and the circuit of the lighting device 1 is protected.

In this way, the first surge protection circuit 9 operates before the second surge protection circuit 10 against the surge applied to the AC 2-wires L1 and L2. Therefore, the first surge protection circuit 9 protects against an induced lightning surge. If the surge protection element of the first surge protection circuit 9 fails and does not operate for a predetermined surge, the second surge protection circuit operates at an operating voltage higher than the operating voltage of the first surge protection circuit 9. 10 protects the electric circuit inside the LED lighting fixture.

Similarly, when the fifth surge protection element Z5 conducts a conductive operation against a relatively high lightning surge applied to the AC two wires L1 and L2, the lighting control circuit 4 and the lighting LED 7 are protected.

Further, the fifth surge protection element Z5 operates in the same manner as the fourth surge protection element Z4, and protects against surges that could not be prevented by the second surge protection circuit 10.

As can be seen from the above, normally, when the lighting control unit (including the rectifier circuit and the LED lighting control circuit) of the lighting LED is not damaged and does not short-circuit, the second protective fuse F3 is set so as not to blow. Therefore, the withstand voltage of each component of the lighting control unit (including the rectifying circuit 6 and the LED lighting control circuit 4) of the lighting LED 7 is set higher than the operating voltage of the first surge protection element Z1 and the second surge protection element Z2. Therefore, the fact that the first surge protection element Z1 and the second surge protection element Z2 do not conduct means that a surge lower than the operating voltage is applied. In this case, the lighting control unit of the lighting LED 7 ( The rectifying circuit 6 and the LED lighting control circuit 4) are not damaged, and as a result, the second protective fuse F3 is not blown, so that the lighting equipment can maintain stable operation.
The present invention can provide similar protection against surges other than lightning surges.

The present invention is not limited to the above-described embodiment, and can provide similar protection against surges other than lightning surges, and includes a technical range that can be changed within the scope of the technical idea of the present invention.

1 ・ ・ ・ ・ ・ Lighting device 2 ・ ・ ・ ・ ・ AC power source 3 ・ ・ ・ ・ ・ Input circuit 4 ・ ・ ・ ・ ・ Lighting control circuit 5 ・ ・ ・ ・ ・ Light emitting part 6 ・ ・ ・ ・ ・ Rectifier circuit 7 ... LED for lighting
8 ... Surge protection device 9 ... 1st surge protection circuit 9A ... 1st surge protection element circuit 10 ... 2nd surge protection circuit 10A ... 2nd surge protection element Circuit 11 ... 3rd surge protection circuit F1 ... 1st fuse F2 ... 1st fuse Z1 ... 1st surge protection element Z2 ... 2nd surge protection element Z3 ...・ ・ 3rd surge protection element Z4 ・ ・ ・ ・ 4th surge protection element Z5 ・ ・ ・ ・ 5th surge protection element L1, L2 ・ AC 2 wire L3 ・ ・ ・ ・ Earth line LK ・ ・ ・ ・ Lighting equipment

Claims (2)

The input circuit that supplies the DC power obtained by converting the AC power supplied from the AC power source, which is an external power source, to the lighting control circuit of the lighting LED by the rectifying circuit is applied to the AC 2 lines. A surge protection element circuit that switches from a non-conducting state to a conductive state at a predetermined operating voltage with respect to a current surge, and the surge that is arranged on the AC two wires on the upstream side (input side) of the surge protection element circuit. At least one of the two AC wires on the downstream side (output side) of the surge protection element circuit and the first fuse that does not blow in the normal operating state of the protection element circuit but blows due to the short-circuit current at the time of failure of the surge protection element circuit. The appropriate capacity that does not blow in the normal operating state of the lighting control circuit but is safely blown due to a current increase or short-circuit current when a component fails in the circuit on the downstream side (output side) of the surge protection element circuit. The setting is such that two fuses are provided, and the fusing current value at which the first fuse is blown is larger than the fusing current value at which the second fuse is blown.
A protective device for LED lighting fixtures. The input circuit that supplies the DC power obtained by converting the AC power supplied from the AC power source, which is an external power source, to the lighting control circuit of the lighting LED by the rectifying circuit is applied to the AC 2 lines. A surge protection element circuit that switches from a non-conducting state to a conductive state at a predetermined operating voltage with respect to a current surge, and the surge that is arranged on the AC two wires on the upstream side (input side) of the surge protection element circuit. The first fuse that does not blow in the normal operating state of the protection element circuit but blows due to the short-circuit current at the time of failure of the surge protection element circuit, and the AC on the downstream side (output side) of the first fuse and the surge protection element circuit. Appropriately arranged on at least one of the two wires and not blown in the normal operating state of the lighting control circuit, but blown due to a current increase or short-circuit current at the time of failure of a component occurring in the circuit on the downstream side (output side) of the surge protection element circuit. A second fuse having a capacity is provided, and the fusing current value at which the first fuse blows is larger than the fusing current value at which the second fuse blows.
The surge protection element circuit includes a first surge protection element and a second surge protection element having a first operating voltage connected in series over two AC wires, and is an intermediate portion between the first surge protection element and the surge protection element. Is connected to the ground line via a third surge protection element.
A protective device for LED lighting fixtures.

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