JPH01150747A - Earth leak breaker for electric device - Google Patents

Abstract

PURPOSE:To provide the earth leak breaker of an electric device which automatically releases an electric pass when a ground is detected and prevents the stop of the motion of a device even when an induction thunderbolt surge occurs to a power source, by a method wherein a discharge means to discharge the induction thunderbolt surge of a commercial source to an earth pole is connected to the commercial source side of an electric pass. CONSTITUTION:An earth leak breaker 10 is provided for an electric device 2, e.g. gas combustion type hot water feeder, used, for example, for a commercial source 1, and is contained in a case 10a made of resin, and the commercial source 1 is fed to the earth leak breaker 10 through terminals 3 and 4. A discharge tube 27 is connected to a lead wire 11b through a resistor 28, and is situated on the power source 1 side as a discharge means being a discharge type surge absorbing element adapted to feed the induction thunderbolt surge of the power source 1 to an earth pole. Thereby, when an induction thunderbolt surge is generated at the power source 1, the induction thunderbolt surge does not flow through the breaker 10 but flows directly to an earth pole 29 to prevent the occurrence of malfunction due to the induction thunderbolt surge. When a ground is generated at the electric device 2, the earth leak breaker 10 is actuated to separate the electric device 2 away from the commercial source, and the feed of a power to the electric device 2 is stopped.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is provided in electrical equipment such as household water heaters and water heaters that use commercial power (line), and is designed to prevent ground faults in order to prevent electric shock, etc. This invention relates to an earth leakage breaker that automatically opens an electrical circuit instantly when a ground fault is detected, and disconnects the point where a ground fault has occurred from the power supply.

[Conventional technology] Large water heaters that use late-night electricity and gas-fired water heaters that operate using commercial power, which are used for household purposes, are sometimes used for baths. −
Finally, an earth leakage breaker is provided to prevent electric shock. In addition, in order to prevent equipment from malfunctioning due to induced lightning surges from the commercial power supply, as shown in Figure 1, as a countermeasure against induced lightning surges, these devices are A discharge tube 32 is provided as a discharge element that causes lightning surge to flow to the earth via a ground electrode.

[Problems to be solved by the invention]However, in conventional equipment connected to commercial power supply via an earth leakage breaker, the main focus was on protecting the equipment.
The discharge tube 32 provided as a countermeasure against induced lightning surge is the first one.
As shown in the figure, grounding on the equipment side with respect to the earth leakage breaker @
33, so when an induced lightning surge occurs, the induced lightning surge flows into the grounding electrode via the earth leakage breaker. Then, there is a problem in that the induced lightning surge causes a current leakage and the disconnector is activated, causing the equipment to stop operating.

The present invention provides an earth leakage breaker installed in electrical equipment that automatically opens the electrical circuit when no ground fault is detected, and also prevents the equipment from operating due to the induced lightning surge even if an induced lightning surge occurs in the power supply. The purpose of the present invention is to provide an earth leakage breaker for electrical equipment that never stops.

[Means for Solving the Problems] The present invention provides an earth leakage breaker that is housed in a case and is provided in an electrical device, and that is provided in an electrical path that connects a commercial power source and the electrical device, The technical means is that a discharging means for discharging the induced lightning surge of the commercial power source to the ground electrode is connected to the power source side, and that the discharging means is housed in the case.

[Operation] According to the present invention, when a ground fault occurs in an electrical device, the earth leakage breaker operates to disconnect the electrical device from the commercial power source, and the power supply to the electrical device is stopped. Therefore, it operates as a safety device against electric shock and the like. Further, when an induced lightning surge occurs in the commercial power supply, the induced lightning surge flows from the discharge means housed in the case and connected to the electrical circuit to the ground electrode and is discharged, thereby protecting electrical equipment from the induced lightning surge. At this time, the induced lightning surge does not flow through the earth leakage breaker, but flows directly from the commercial power source to the ground electrode. Therefore, earth leakage circuit breakers do not operate against induced lightning surges.

[Effects of the Invention] According to the present invention, an earth leakage breaker operates when a ground fault occurs, and when an induced lightning surge occurs, the induced lightning surge is discharged to protect electrical equipment. When an induced lightning surge is discharged, the earth leakage breaker does not operate, so electrical equipment is not affected by the induced lightning surge and can continue to operate with power supplied from the commercial power source.

Furthermore, since the discharging means is housed within the case, it can be easily attached to electrical equipment.

[Example code] Next, the present invention will be explained based on examples.

FIG. 1 shows the configuration of an earth leakage breaker 10 of the present invention.

This earth leakage breaker 10 is installed in an electrical device 2 such as a gas combustion water heater that uses a single-phase AC commercial power source 1, and is housed in a resin case 10a whose specific shape is not shown. , commercial power supply 1 is supplied to earth leakage breaker 10 via terminal 3.4.

Terminal 3.4 is connected to relay contact 12 by conductors 11a and 11b.
It is connected to terminal 5.6 via a and 12b, and is connected to commercial power supply 1.
The electric power supplied from the terminal 5.6 is supplied to the electrical equipment 2 from the terminal 5.6.

Relay contacts 12a and 12b are both opened and closed by a relay 12, which is driven by a transistor 14 controlled by a control circuit 13, and when driven, each contact opens.

The control circuit 13 includes relay contacts 12a, 12b and terminals 5.
6 and a differential current transformer 15 for ground fault detection.
It outputs a control signal based on the output voltage from the differential current transformer 15, and in this embodiment, it is composed of an IC or the like with predetermined characteristics, and when a predetermined voltage is output from the differential current transformer 15, the transistor It outputs 14 switching signals.

The differential current transformer 15 is an integrated detector consisting of a coil equipped with an annular core and two conductive wires fixed in a predetermined positional relationship inside the annular core. When a current difference is generated in each of the conducting wires, a voltage corresponding to the current difference is generated.

These relays 12 and control circuit 13 are connected to diodes 16
It is operated by DC power that is rectified to a predetermined voltage by a resistor 17 and supplied by a smoothing capacitor 18. Note that the resistor 19 is a voltage drop resistor for the control circuit 13 that operates at low voltage, and the resistors 20 and 21 are for the differential current transformer 15.
This is a resistor for input adjustment from.

Further, diodes 22 and 23 are a flywheel diode and a light emitting diode for indicating operation, respectively.

Furthermore, the switch 25 that connects the conductors 11a and 11b via the resistor 24 is a test switch for testing the operation of the control circuit 13 instead of actually generating a ground fault.
is a reset switch.

In this embodiment, the earth leakage breaker 10 having the above configuration is provided with a discharge tube 27 connected to the conducting wire 11b via a resistor 28. This discharge tube 27 is especially provided on the commercial power supply 1 side as a discharge means, which is a discharge type surge absorbing element (arrestan), in order to flow the induced lightning surge of the commercial power supply 1 to the ground electrode. If an induced lightning surge occurs in 1, the induced lightning surge will be removed by the earth leakage breaker 10.
Instead of flowing inside, it flows directly to the ground electrode 29. Therefore, it is possible to eliminate malfunctions of the earth leakage breaker 10 due to induced lightning surges.

Note that the Zener diode 30 allows an induced lightning surge to flow even when the terminal 3.4 is reversely connected to the commercial power source 1. Also, resistor 31
The discharge tube 32 is a discharge circuit conventionally provided in the electrical equipment 2, and protects the electrical equipment 2 in the event that an induced lightning surge flows into the earth leakage breaker 10.

The earth leakage breaker 10 of this embodiment having the above configuration operates as follows.

If a ground fault occurs while the electrical equipment 2 is in use, the differential current transformer 15
A voltage is generated at , and this voltage is sent to the control circuit 13 via the resistor 20.21.

The control circuit 13 stops the switching signal to the transistor 14 when this voltage is equal to or higher than a predetermined voltage. Then, the relay 12 opens the relay contacts 12a and 12b, and the power supply to the electric device 2 is stopped.

Therefore, the user of the electrical device 2 can be protected from electric shock and the like.

On the other hand, when an induced lightning surge occurs in the commercial power supply 1, when the induced lightning surge flows into this earth leakage breaker 10 from the terminal 4, it flows directly into the earth leakage breaker 10, and when it flows from the terminal 3, it flows through the resistor 28 and the discharge Flows into pipe 27. Therefore, the induced lightning surge is caused by the differential current transformer 15
Therefore, it will not be mistakenly detected as a ground fault.

Therefore, the electrical equipment 2 continues to operate even after the induced lightning surge occurs.

As described above, according to the present invention, when a ground fault occurs in the electrical equipment, the power supply to the electrical equipment is stopped, so that the user can be protected. Furthermore, when an induced lightning surge occurs in the commercial power supply 1, the induced lightning surge does not pass through the earth leakage breaker 10 and flow into the electrical equipment.
You can continue to use electrical equipment.

Furthermore, since the discharge means, which is a surge absorbing element such as a discharge tube, is housed in a case that houses the earth leakage breaker, installation is easy.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the earth leakage breaker of the present invention. In the figure, 1... commercial power supply, 2... electrical equipment, 10...
- Earth leakage breaker, 10a... Case, 11a... Conductor (electrical path), 11b... Conductive wire (electrical path), 27... Discharge tube (discharge means), 29... Ground electrode.

Claims (1)

[Scope of Claims] 1) In a current leakage or disconnection switch that is housed in a case and is provided in an electrical device and is provided in an electrical path that connects a commercial power source and the electrical device, the commercial power source side of the electrical path includes: A discharge means for discharging induced lightning surge of the commercial power source to a ground electrode is connected, and the discharge means is housed in the case. 2) A leakage or disconnection circuit for electrical equipment according to claim 1, wherein the discharge means comprises a resistor and a discharge tube.