JP4498899B2 - Electric circuit switch device and electric drum device equipped with the electric circuit switch device - Google Patents

Description

  The present invention relates to, for example, an electric circuit switchgear that is inserted in an electric circuit that supplies power to a load such as an electric tool, and an electric drum device that includes the electric circuit switchgear, and in particular, the load when power is restored after a power failure. The present invention relates to an apparatus of this type that can ensure the safety of workers and equipment related to a power tool or the like without sacrificing convenience.

  In general, when a power outage continues for a certain period of time at a site where electric equipment such as an electric drill or other electric tool or welding machine is powered from an electric drum, etc., to investigate the cause of the power outage and restore power In addition, the operator goes to the power source to check the state, and investigates and removes the cause. For this reason, there is a state where the worker is away from the electric tool, the welding machine, or the like, or the other worker is facing the power recovery operation and the original worker cannot recognize the state of the power recovery operation. appear.

  Therefore, when power is restored, consideration is required to prevent the above-described electrical equipment from inadvertently resuming operation and damaging objects and human bodies. Also, if the power breaker continues for a certain period of time with the earth leakage circuit breaker turned on and then recovers, the motor may be restarted suddenly without confirming the load, or the heaters may be forgotten to switch off. A function to prevent the occurrence of a fire is required.

  Conventionally, an earth leakage circuit breaker with a function of interrupting power recovery that meets the above-described requirements has been proposed. In this conventional proposal, the leakage breaker with a power interruption function is provided on the power supply side of the open circuit portion of the leakage breaker with a delay circuit that responds to a change in voltage between the electric circuits with a predetermined delay, and at the output terminal of this delay circuit. The drive part of the relay is connected. A circuit in which a trip coil and a break contact of the relay are connected in series between any two electric circuits on the load side of the leakage breaker, and a leakage detection circuit unit for functioning as an original leakage breaker ( The amplifier circuit section of the zero-phase current transformer output) is connected in parallel.

In the conventional earth leakage circuit breaker with the power interruption function having such a configuration, the above-described break contact is maintained in the open state until a certain time corresponding to the time constant of the delay circuit elapses after the power failure occurs. For this reason, even if the voltage of the electric circuit on the load side of the earth leakage circuit breaker is established by power recovery within this fixed time, the trip coil is not supplied with power and the circuit breaker maintains a closed state. Therefore, there is no inconvenience that the handle of the earth leakage circuit breaker trips at every momentary power failure and the power supply is cut off. As soon as the voltage on the load side of the earth leakage breaker is established by power recovery, the trip coil is supplied with power, and the circuit breaker shifts to an open state, that is, trips (for example, Patent Document 1).
JP 09-115412 (paragraphs 0001 to 0010, FIGS. 1 and 3)

  The conventional technology described above has the following problems. That is, in the technique disclosed in Patent Document 1, a delay circuit is intentionally provided so as not to respond to a short-time power failure. Therefore, depending on the value of the time constant of the delay circuit, the power is restored after a short-time power failure. Then, power supply to the load-side power tool etc. is resumed immediately.For example, when the operator touches the blade edge of the electric drill with a finger or the blade edge touches equipment such as equipment. If the power supply is resumed, the cutting edge may suddenly rotate and the operator may be injured or the object may be damaged.

  On the other hand, when power is restored after a power failure that has continued for a certain time instead of a short time as described above, the break contact of the relay is closed, so that the voltage on the load side of the leakage breaker is Once established, it will trip uniformly regardless of whether the load is actually connected or not. If the value of the time constant of the delay circuit is appropriate, it can be said that it is a desirable state in terms of ensuring safety without the possibility of inadvertent resumption of power supply as described above.

  However, if the operator has already taken safety measures such as disconnecting the power tool or other load from the outlet or switching it off to ensure safety, the circuit breaker will always trip once regardless of this. However, it is not only meaningful from the viewpoint of ensuring safety, but it is also disadvantageous in terms of convenience, such as having to perform a return operation uniformly regardless of whether safety measures have already been taken. End up.

  The present invention has been made paying attention to the problems in the prior art as described above, and even when power is restored after a relatively short power failure, a load is connected to the electric circuit within a certain time after power restoration. If it is detected, the power supply is turned off to ensure safety.On the other hand, if it is not detected that a load is connected to the circuit within a certain time after the power recovery, the power supply is maintained, and no return operation is performed. It is an object of the present invention to provide an electric circuit switch device of this type that eliminates waste and annoyance that must not be performed, and an electric drum device including the electric circuit switch device.

In order to solve the above-described problems, the present application proposes the following techniques.
(1) An electric circuit switch that is inserted in an electric circuit between a power receiving end connected to a power source and a power feeding end that supplies power to the load and opens the electric circuit in response to a supplied operation command, and the power receiving end Timer means arranged to perform a time-limited operation for a predetermined time from the time of power restoration after the occurrence of a power failure relating to the power supplied to the power supply, and arranged to detect the current of the electric circuit on the load side of the electric circuit switch And a current detection means for providing an operation command to the electric circuit switch when a current is detected within a time limit operation time by the timer means.

(2) The timer means is connected between the load-side electric circuits of the electric circuit switch, and is configured to start a timed operation in synchronization with a rise in voltage between the electric circuits due to power recovery. The electric circuit switchgear according to (1).
(3) The current detection means is characterized in that a make contact for maintaining a closed state during a time limit operation period of the timer means is inserted in series in the current detection coil. The electric circuit switchgear according to claim 1.

(4) The electric circuit switch is an earth leakage circuit breaker configured to open the electric circuit in response to the operation command, according to any one of (1) to (3), Electric circuit switchgear.
(5) The circuit breaker is a circuit breaker configured to open the circuit in response to the operation command, (1) to (4), Electric circuit switchgear.
(6) An electric drum apparatus comprising the winding circuit casing in the winding circuit case according to any one of (1) to (5).

  Even when power is restored after a relatively short power failure, if it is detected that a load is connected to the circuit within a certain period of time after power is restored, power is immediately turned off to ensure safety, while power is restored. When it is not detected that a load is connected to the electric circuit within a certain period of time after power is supplied, power supply is maintained, and the return operation must be performed uniformly regardless of whether or not safety measures have been taken. It is possible to embody such a type of electric circuit switching device that has been wiped out, and an electric drum device including this electric circuit switching device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram showing an electric circuit switching device to which the present invention is applied. In the figure, the electric circuits 11 and 12 on the load side of the plug 10 are each contacts 21 of an earth leakage circuit breaker (ELCB) 20 which is an electric circuit switch for opening and closing the electric circuit in response to an operation command described later. , 22 to the respective outlets 31, 32, 33, 34 that can supply power to the loads L 1, L 2, L 3, L 4. As the electric circuit switch, a circuit breaker configured to open the electric circuit in response to an operation command may be applied instead of such an ELCB.

  Between the electric circuits 11 and 12 on the load side of the earth leakage breaker 20, a predetermined time-limited operation (for example, a time when power is restored after a power failure, that is, a predetermined time point at the rising of the voltage between the electric circuits 11 and 12, for example, A time limit circuit unit 41 of a timer 40 is connected as a timer means for performing (from about 500 milliseconds to 1 second). In addition, a CT (its coil) 51 is mounted on the electric circuit 11, and an amplification command 42 for issuing an operation command (trip command Tc) to the make contact 42 and the earth leakage breaker 20 for performing the time limit operation of the timer 40 described above. A circuit 52 is connected in series.

  The coil 51, the make contact 42, and the amplifier circuit 52 form a closed circuit as shown in the figure, and the current detection means 50 is configured. This current detection means 50 is arranged so as to detect the current of the load-side electric circuit 11 (may be 12) of the electric circuit switch (leakage breaker 20) by means of the coil 51, and the time limit operation by the timer means (timer 40). When the current is detected within the time, an operation command (trip command Tc) is given to the electric circuit switch 20. The make contact 42 is kept closed during the time limit operation period of the timer 40.

  FIG. 2 is a timing diagram for explaining the operation when power is restored after a power failure continues for a certain time or more in the apparatus of FIG. 1 and a load current is detected within a predetermined time after power restoration. 2A shows the occurrence of power failure and power recovery of the power supplied from the plug 10, FIG. 2B shows the opening / closing timing of the make contact 42 of the timer 40, and FIG. FIG. 2D shows the generation timing of the trip command Tc, and FIG. 2E shows the opening and closing of the contacts 21 and 22 of the leakage breaker (ELCB) 20. Each situation is represented.

  When the power failure continues for a certain time or more at the timing shown in FIG. 2A, the timer 40 starts the time limit operation at the timing when the power is restored as shown in FIG. 2B, and the predetermined load monitoring time t1 ( In the present embodiment, the make contact 42 is closed during the period of about 500 milliseconds to 1 second) and the state is maintained. As shown in FIG. 2C, when the load current is detected within the load monitoring time t1, as shown in FIG. 2D, the amplifier circuit 52 of the current detection means 50 immediately outputs the trip command Tc. And give to the earth leakage breaker (ELCB) 20. In response to the trip command Tc, the earth leakage breaker (ELCB) 20 opens its contacts 21 and 22 as shown in FIG.

  As described above, in the apparatus according to the present embodiment, when a power failure continues for a certain time or longer and power is restored, generation of load current is monitored during a predetermined load monitoring time t1 from the power restoration timing, and this period t1 When the occurrence of load current is detected, the contacts 21 and 22 of the earth leakage breaker (ELCB) 20 are immediately opened to cut off the power supply to the load, and an electric drill or other electric equipment connected as a load Avoid the danger of inadvertent restarts and ensure the safety of people and equipment.

  FIG. 3 is a timing diagram for explaining the operation in the case where the power failure continues in the apparatus of FIG. 1 for a certain time or more and power is restored and no load current is detected within a predetermined time after power restoration. As in FIG. 2, FIG. 3A shows the occurrence of power failure and power recovery of the power supplied from the plug 10, and FIG. 3B shows the timing of opening and closing the make contact 42 of the timer 40. 3 (c) shows the detection status of the load current of the electric circuit 11 by CT50, FIG. 3 (d) shows the generation timing of the trip command Tc (not generated in this case), and FIG. The switching states of the contacts 21 and 22 of the earth leakage breaker (ELCB) 20 (in this case, the closed state is maintained) are shown.

  When the power failure continues for a certain time or more at the timing shown in FIG. 3A, the timer 40 starts a time limit operation at the timing when the power is restored as shown in FIG. 3B, and the predetermined load monitoring time t1 ( In the present embodiment, the makeup contact 42 maintains its closed state during a period of about 500 milliseconds to 1 second), which is similar to the situation described above with reference to FIG. However, in FIG. 3, it is assumed that the load current is not detected within the load monitoring time t1, and the load current is detected after the period t1 has elapsed, as shown in FIG. 3C.

  This may be the case, for example, when the operator has already taken safety measures to disconnect the power tool or other load from the outlets 31 to 34 or to switch off the electrical equipment to ensure safety before power is restored after a power failure. This is the case when a load is connected to an outlet for the first time after power is restored. In such a case, measures to ensure safety have already been taken, or there is essentially no fear as described above. It is useless to sever.

  Therefore, as shown in FIG. 3D, the amplifier circuit 52 of the current detecting means 50 does not issue the trip command Tc, and as shown in FIG. (ELCB) 20 maintains the closed state of its contacts 21 and 22. For this reason, after the load monitoring time t1 has elapsed, the load device that has been restarted by a normal operation or has started to operate newly has been turned off once and asked to restart the contacts 21 and 22 The operation state can be normally maintained without inconvenience such as being unable to operate. In the above description, the leakage breaker (ELCB) 20 itself has a function as a normal leakage breaker that detects and trips the zero-phase current, and is similar to other well-known ELCBs.

  FIG. 4 is a diagram showing an electric drum apparatus provided with the electric circuit switching device of FIG. In FIG. 4, corresponding parts to those in FIG. 1 are denoted by the same reference numerals. The illustrated electric drum apparatus 100 includes a hollow cylindrical take-up drum casing 110 that winds up an electric cord 15 provided with a plug 10 at the tip and having a conductive wire connected to each of the electric paths 11 and 12 of FIG. A drum frame 130 having flange-shaped flange members 121 and 122 provided on both side surfaces of the take-up drum casing 110, and a support frame constituted by a metal pipe or the like that supports the drum section 130 and is self-supporting. 140. In addition, a handle 123 for winding operation is provided in the vicinity of the outer periphery of the flange member 121 so as to protrude to the outside, and a known carrying handle 141 is attached to the support frame 140 at the top position.

  The take-up drum casing 110 includes the above-described earth leakage breaker (ELCB) 20 with reference to FIG. 1, outlets 31 to 34, a timer 40, a current detection means 50, and the like. The load stop circuit 60 is accommodated, and as shown in the drawing, the load stop circuit 60 is disposed on one side plate portion 111 side of the take-up drum casing 110 so as to be partially exposed in a posture and arrangement suitable for each function. Yes.

  If the electric drum apparatus 100 as shown in FIG. 4 is used, and an electric drill or other electric tool such as an electric tool or a welding machine is used by taking power from the respective outlets 31 to 34, refer to FIGS. If the power is restored after a power failure for a certain period of time, electrical equipment may inadvertently resume operation and damage equipment or the human body. The risk of fires due to forgetting to turn off the switch is cleared.

  At the beginning of using the electric drum device 100, after the plug 10 at the tip of the electric cord 15 is connected to the power source, the load monitoring time t1 described with reference to FIGS. 2 and 3 is awaited. It is necessary to activate a load such as a power tool. However, as described above, since the load monitoring time t1 is set to, for example, about 500 milliseconds to 1 second, the electric cord 15 of the electric drum device 100 is pulled out by, for example, a few dozen meters and the plug 10 at the tip is connected to the power source. The load monitoring time t1 is expected to have already passed until the worker who has returned to the installation position of the electric drum device 100 at the walking speed, and in an ordinary case, the electric drum may wait for the load monitoring time. There is no risk of impairing convenience when using the device 100.

It is a circuit diagram showing the electric circuit switchgear to which this invention is applied. FIG. 3 is a timing diagram for explaining an operation when power is restored after a power failure continues for a certain time or more in the apparatus of FIG. 1 and a load current is detected within a predetermined time after power restoration. FIG. 3 is a timing diagram for explaining an operation when power is restored after a power failure continues for a certain time or longer in the apparatus of FIG. 1 and a load current is not detected within a predetermined time after power restoration. It is a figure showing the electric drum apparatus provided with the electrical circuit switching device of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Plug, 11, 12 ... Electric circuit, 15 ... Electric cord, 20 ... Earth leakage breaker (ELCB), 21, 22 ... Contact, 31, 32, 33, 34 ... Outlet, 40 ... Timer, 41 ... Time limit circuit part, 42 ... make contact, 50 ... current detection means, 51 ... CT, 52 ... amplifier circuit, 100 ... electric drum device, 110 ... winding drum casing, 111 ... side plate, 121,122 ... flange member, 123 ... handle, 130 ... drum part, 140 ... support frame, 141 ... handle for transportation

Claims (6)

  An electric circuit switch that is inserted in an electric circuit between a power receiving end connected to a power source and a power feeding end that supplies power to the load and opens the electric circuit in response to a supplied operation command, and is supplied to the power receiving end Timer means arranged to perform a time-limited operation for a predetermined time from the time of power recovery after the occurrence of a power failure relating to the power source, and the timer arranged to detect the current of the electric circuit on the load side of the electric circuit switch An electric circuit switching device comprising: current detection means for giving an operation command to the electric circuit switch when a current is detected within a time limit operation time by the means.   The timer means is connected between the load-side electric circuits of the electric circuit switch, and is configured to start a timed operation in synchronization with a rise in voltage between the electric circuits due to power recovery. The electric circuit switchgear according to 1.   3. The current detection unit according to claim 1, wherein a make contact that maintains a closed state during a time limit operation period of the timer unit is inserted in series with a current detection coil. Electric circuit switchgear.   The electric circuit switch according to any one of claims 1 to 3, wherein the electric circuit switch is an earth leakage circuit breaker configured to open the electric circuit in response to the operation command. .   The electric circuit switch according to any one of claims 1 to 4, wherein the electric circuit switch is a circuit breaker configured to open the electric circuit in response to the operation command.   An electric drum apparatus comprising the electric circuit switching device according to any one of claims 1 to 5 in a winding drum casing.

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