JPS6145696Y2 - - Google Patents

Description

[Detailed Description of the Invention] Field of the Invention This invention relates to an electrical safety device, particularly a portable emergency safety device that quickly disconnects a power distribution circuit from a power source in the event of an emergency.

BACKGROUND OF THE INVENTION Emergency pushbuttons that cut off power in the event of an emergency are widely used in laboratories, shops, factories, and homes. Such devices usually consist of a large push-button switch, located in an easily accessible location and painted red for easy identification, to quickly cut off power in the event of an emergency. In conventional devices, the emergency pushbutton activates a normally open pushbutton switch that is used to energize the trip coil of the breaker that protects the power distribution circuit. Therefore, special wiring must be installed between the breaker and the location where the emergency push button is installed. The cost and complexity of this dedicated wiring often means that fewer emergency pushbuttons are installed than necessary. Sometimes the expense and complexity has made installing such an emergency power cut-off device completely negligible.

As another example of the prior art, a security device disclosed in Japanese Utility Model Application Publication No. 48-98083 is known. This security device comprises a current transformer, a ground fault alarm with a buzzer connected to be activated by the output of the current transformer, a connector or outlet, a detector and a plug, all of its components. Not only must they be wired to each other and to a power source, but detectors must be mounted in special ways on windows and doors to detect intruders. In other words,
This prior art technique corresponds to the conventional emergency pushbutton described above, since each part of the device must be permanently installed and wired at a preselected location.

Furthermore, the 48th Japanese Patent Publication discloses that a ground fault detection relay can be operated and disconnected by forced grounding.
Needless to refer to Publication No. 36058, the present utility model applicant proposes a configuration for testing ground faults and disconnections for usability and accurate calibration by intentionally establishing a ground condition. I also know it well.

Currently, power distribution networks in most industrial and commercial installations as well as domestic installations require protection devices. This protection device protects against currents and overcurrents due to earth faults, i.e. leakage to earth, and for this purpose has a value significantly lower than the overload current trip level of the protection device used, such as a ground fault current of 5 milliamps. Grounding faults and disconnectors designed to de-energize the faulted network or its branches in response to ground fault currents are used.

DISCLOSURE OF THE INVENTION The object of this invention is to be portable anywhere, even in a person's pocket, and to be able to be used by individuals whenever there is electrical power that normally flows from a circuit protected by a grounding hazard or disconnection means. To provide a simple and inexpensive portable emergency safety device that is small enough to be used as an emergency push button.

The invention thus includes a line conductor and a grounding conductor and has an outlet connected to these for receiving the connection plug of an electrical appliance to be supplied with power from the power supply circuit, and which A portable device for rapidly deenergizing said power supply circuit protected by ground fault-proofing means adapted to trip in response and thereby de-energize said power supply circuit. An emergency maintenance device comprising a plug having pins which, when inserted into one of the outlets, electrically connects the two pins with the line conductor and the ground wire. means disposed within said plug and forming an electrical connection between said two pins, said ground wire being connected from said line conductor when said plug is inserted into any outlet and said switch is closed; the electrical connection includes a manually operable normally open switch to complete a current path through the electrical connection for ground fault current flowing to the ground fault current; and has an impedance sufficiently higher than the predetermined level to ensure that the ground fault is exceeded and the tripping means is tripped.

This portable emergency security device according to this invention is
They can be mass-produced cheaply and are readily available whenever a sudden need to turn off power may arise. This device, which is no more than the size of an ordinary plug in a power panel such as a power tool, can be carried conveniently in a person's pocket to any appliance to be operated, tested or repaired. It therefore provides protection even in locations where no fixed "emergency push button" is installed. On top of that,
The most important thing is that the device of this invention is a truly and extremely effective emergency safety device as long as it can cut off power in less than one second with absolute reliability when activated in an emergency situation. That's true.

Embodiment of the invention As shown in the drawing, a three-wire power supply circuit 12
is powered by a power source (not shown) and connected to line conductors, namely phase conductor L, neutral conductor N and ground conductor G.
Equipped with. In the drawings, it is assumed that the left side is the power supply side and the right side is the load side. A plurality of three-prong receptacles or outlets are connected to the power supply circuit 12, only one of which is shown in the drawings. A corresponding electrical appliance plug is inserted into the electrical outlet 14, thereby supplying power to the electrical appliance. As shown, the outlet 14
has a terminal 22 connected to the phase conductor L, a terminal 24 connected to the ground conductor G, and a terminal 26 connected to the neutral conductor N.

A ground fault disconnector 16 is inserted into the power supply circuit 12 between the power source and the first outlet 14 . The ground fault disconnector 16 is connected to the power supply circuit 12
It has a contact 18 that can be separated in series with the phase conductor L. In a manner well known to those skilled in the art, the current flowing from the phase conductor L to ground is sensed, and when the ground fault current exceeds a predetermined level, the contacts 18 are disconnected or opened, thereby preventing a ground fault in the power supply circuit 12. The section after the disconnector 16 is deenergized.

The level of ground fault current that causes a ground fault to trip the disconnector 16 varies depending on the application. For example, a "personal protection" grounding fault or disconnect switch designed to prevent a person from accidentally touching phase conductor L and ground simultaneously and causing serious injury is designed to trip at a level of approximately 5 milliamps. This is, of course, considerably less than the overcurrent trip level of the ground fault or disconnector 16, and is designed only to prevent damage to the conductor itself by overcurrent levels in the range of several amperes or more. This is a function that has been updated.

In this invention, means are provided for deliberately starting the flow of current from the phase conductor L to earth. When such current reaches the ground fault current trip level of the ground fault interrupter 16, the ground fault interrupter 16 trips and de-energizes the power supply circuit. In one preferred embodiment of the invention, the plug 20 is
Although its appearance is the same as the plug of the power cord of an electric appliance that is supplied with power from the power supply circuit 12,
It has been modified to include a push button switch 34 having contacts 36. The plug 20 has terminals 22, 2 connected to the phase conductor L, the ground conductor G, and the neutral conductor N, respectively.
Also includes pins 28, 32, 30 which cooperate with 4, 26. Contact 36 of pushbutton switch 34 is connected in series with a resistor 38, and this series circuit is connected between pins 28 and 32 of plug 20. push button switch 3
Pressing 4 creates an electrical circuit between pins 28 and 32. When plug 20 is inserted into outlet 14 and push button switch 34 is pressed, current flows from phase conductor L through terminal 22, pin 28, resistor 38, contact 36, pin 32 and terminal 24 to ground wire G. The resistance value of the resistor 38 is
is selected depending on the voltage applied to power supply circuit 12 to cause a ground fault current greater than the ground fault current trip level of . Therefore, push button switch 3
When 4 is pressed, the ground fault disconnector 16 trips, deenergizing the power supply circuit 12 and de-energizing the portion of the ground fault interrupter 16 (power supply circuit 12) after the contact 18. separate from AC 115V
Typical applications for circuits include grounding faults and disconnectors16.
can be set to a ground fault current trip level of 5 milliamps, so that a person can touch the phase conductor L and ground simultaneously without serious injury. By connecting a 10 kilohm resistor 38, pressing the push button switch 34 causes a ground fault current of 12 milliamps to flow. This current level is significantly higher than the level required to trip disconnector 16 in a ground fault, but still significantly lower than the overcurrent trip level (which would damage the conductors of power supply circuit 12).

By selecting the resistance value of the resistor 38 to a value that allows a current to flow at a level considerably higher than the trip level of the disconnector 16 in the event of a ground fault under normal voltage conditions, it is possible to prevent the line voltage from dropping completely in the event of an emergency. Even if the current flowing through the resistor 38 can still fail to ground or trip the disconnector 16, there is sufficient margin. The invention disclosed herein can, of course, be used in polyphase circuits protected by polyphase ground faults and disconnectors. All that is required is for current to flow from one phase to ground. A ground fault or disconnect will trip regardless of which phase is selected.

Resistor 38 is, of course, not necessary for the operation of this invention. However, resistor 38, when present, limits the ground fault current level and allows the use of less expensive lower current rated contacts 36. Other impedances may be used in place of resistor 38 to perform this current limiting function.

Effects of the Invention By providing means in the plug 20 for initiating the flow of ground fault current, various advantages are obtained. The plug is connected to one of the outlets 14 of the power supply circuit 12.
Or you can plug it into any outlet. The cost of each plug 20 is much lower than conventional emergency power shutoff buttons that require dedicated wiring to the shutoff trip coil. Additionally, if a temporary remote emergency pushbutton is needed, it can be done in a simple and convenient manner by using a regular extension cord that plugs into the outlet 14 and by plugging the plug 20 into the other end of the extension cord. Ru. Plug 20 can be activated whenever emergency power disconnection capability is required. Additionally, a single plug 20 can be installed by the operator into any desired location of the outlet 14.

The invention therefore provides an emergency power cut-off device that can be installed very inexpensively in existing power supply circuits with ground fault protection. Additionally, the invention provides a highly flexible and convenient means of providing emergency power interruption capability to a wide range of locations.

[Brief explanation of the drawing]

The drawing is a schematic circuit diagram showing a partially perspective view of a power supply circuit incorporating this invention. 12 is a power supply circuit, L is a phase conductor, N is a neutral wire, G is a grounding wire, 14 is an outlet, 16 is a ground fault disconnector, 20 is a plug, 22, 24, and 26
is the outlet terminal, 28, 30, and 32 are the plug pins, 34 is the push button switch, 36 is the contact, 38
is resistance.

Claims (1)

[Claims for Utility Model Registration] 1. A utility model having a line conductor and a grounding conductor, and having at least one outlet for receiving a connecting plug of an electrical appliance connected to these conductors and to be supplied with power by a power supply circuit. and in a portable emergency safety device for rapidly deenergizing said power supply circuit protected by a ground fault suppression means adapted to trip in response to a predetermined level of ground fault current. , consisting of a multi-pin plug adapted to be inserted into any of the above-mentioned outlets, so that the two pins of this plug are electrically connected to the above-mentioned line conductor and the above-mentioned ground wire, and the above-mentioned An impedance element and a manually operable normally open switch contact are arranged in the plug and connected to form a series circuit between a line conductor pin and a grounding wire pin, and the series circuit is formed when the plug connects to the outlet. When the line conductor is inserted into any of the lines and the switch is closed, a ground fault current can be caused to flow from the line conductor to the ground wire,
The series circuit is further characterized in that the series circuit has an impedance value that causes the ground fault current to substantially exceed the predetermined level and thus exceed the ground fault by an amount sufficient to ensure tripping of the disconnection means. A portable emergency safety device. 2 Claim No. 1 for Utility Model Registration characterized in that the switch is an instant contact type push button switch
Portable emergency safety device as described in Section 1. 3. The portable emergency safety device according to claim 1 or 2, wherein the impedance element is a resistor. 4. A claim for utility model registration characterized in that the series circuit between the line conductor pin and the ground conductor pin has an impedance value that causes a ground fault current of at least twice the predetermined level to flow when the switch is closed. A portable emergency safety device according to any one of items 1 to 3.