JPH1082805A - Portable residual voltage discriminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply investigate the nature and cause of the residual voltage after a power supply is opened by providing a pair of residual voltage detecting terminals, and connecting a switching AC/DC voltage discriminating means and an indicator lamp in parallel between the terminals. SOLUTION: The tip of a pickup 20 is brought into contact with the conduction portion of an electric circuit having a residual voltage, an AC/DC selector switch 53 is switched to the side of an AC voltmeter 51 or to the side of a DC voltmeter 52, and the voltage value is measured on either side. Then, a indicator lamp switch 62 is turned on to light an indicator lamp 61. If the lighted state is continued, it is judged that the residual voltage is caused by the real voltage due to the mixed contact of wires. If the indicator lamp 61 is temporarily lighted then gradually becomes dark and is finally tuned off, it is judged that the residual voltage is caused by the electrostatic capacity in the circuit. If the indicator lamp 61 is not lighted or the AC voltmeter 51 indicates zero when the indicator lamp switch 62 is tumed on, it is judged that the residual voltage is caused by induction in the circuit. The cause of the residual voltage can be accurately judged by this method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable residual voltage detector for determining the cause of a residual voltage appearing in an electric circuit.

[0002]

2. Description of the Related Art In an inspection of an electric system at a factory, if a voltage still exists in an electric circuit even after a power supply of a predetermined electric circuit is opened, it is necessary to investigate a cause of the residual voltage. However, conventionally, in such a case, a tester is used, or a temporary circuit is assembled if necessary. FIGS. 5, 6 and 7 show conventionally used instruments. FIG. 5 shows a voltage tester, FIG. 6 shows a temporary circuit for voltage determination, and FIG. 7 shows a temporary circuit for continuous voltage discharge.

If the tester 1 is used, it is possible to know whether the residual voltage is an AC voltage or a DC voltage and its voltage value. The temporary circuit in FIG. 6 includes a lamp 3, a protective fuse 4, a temporary knife switch 5, and a pickup 6. If the pickup 6 is applied to a part of the circuit and the knife switch 5 is turned on, the lamp 3 continues to light. It can be seen that the cause of the residual voltage is the actual voltage due to the contact of the wiring. 7 includes a resistor 8, a protective fuse 9, a temporary knife switch 10, and an alligator clip 1.
By performing continuous discharge of residual voltage induced by sandwiching a part of the circuit with the alligator clip 11, it is possible to perform operations such as contact resistance measurement of the relay without any voltage.

[0004]

The phenomenon that a voltage remains in an electric circuit even after the power is released is often found at the stage of checking for a poor contact of a relay in the electric circuit. In addition to this, not only can the original work (such as investigating poor contact of the relay) be undertaken, but also a lot of time is spent investigating the cause of this residual voltage and producing the above temporary circuit to deal with it. Result. In addition, since the temporary circuit is manufactured each time at the discretion of the person performing the inspection work, there is a risk of incorrect wiring due to forgetting or misunderstanding,
There were also safety issues.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has an integrated circuit having a voltage discriminating function capable of easily ascertaining the nature and cause of a voltage remaining in an electric circuit after power is turned off, or a residual voltage discharging function additionally. It is an object of the present invention to provide a simplified portable residual voltage discriminator.

[0006]

In order to achieve the above object, the present invention has a pair of terminals for detecting residual voltage, between which a switching type AC / DC voltage discriminating means and an indicator lamp are connected in parallel. Characterized in that it is connected to Further, the present invention is characterized in that a manually operable indicator light switch is connected in series with the indicator light. Further, the present invention is characterized in that it has a pair of residual voltage detecting terminals, and a switching type AC / DC voltage discriminating means, an indicator lamp, and a rapid decay element are connected in parallel between the terminals. Also, the present invention provides that the pair of residual voltage detection terminals is a clip, and that a manually operable indicator light switch is connected in series with the indicator light, and that a manually operable switch is connected in series with the rapid decay element. Features.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.

FIG. 1 is a plan view of an embodiment of a portable residual voltage detector according to the present invention, and FIG. 2 is an internal circuit diagram of the portable residual voltage detector.

As shown in FIG. 1, a portable residual voltage discriminator 100 of the present invention is provided in a small plastic insulated container in a protective circuit 40, a voltage discriminating circuit 50 shown in FIG.
A voltage attenuation display circuit 60 is built in compactly, and an AC voltmeter 51, a DC voltmeter 52,
AC / DC switch 53, indicator light 61, indicator light switch 6
2 are arranged, and a pair of pickups 20 can be inserted into the upper surface. A double filament is employed as the indicator lamp 61 of the voltage attenuation display circuit 60 so that the residual voltage attenuation state can be checked at a glance.

The circuit configuration will be described with reference to FIG.

The pickup 20 can detect the voltage remaining in the electric circuit by applying its tip to a conductive part of the electric circuit to be inspected.

The protection circuit 40 comprises a fuse 41 for preventing an excessive current from flowing into the portable residual voltage detector 100 at the time of inspection.

A voltage determination circuit 50 includes an AC voltmeter 51 and a DC voltmeter 5 for determining whether the residual voltage is AC or DC.
2 and an AC / DC switch 53 for switching these voltmeters.

The voltage attenuation display circuit 60 comprises an indicator light 61 and an indicator light switch 62 for determining whether the residual voltage is an actual voltage, an induction voltage, or an electrostatic capacitance. .

Next, the portable residual voltage discriminator 10 having the above-described structure is used.
A procedure for determining the cause of the residual voltage using 0 will be described.

First, the tip of the pickup 20 is applied to a conductive part of the electric circuit where the residual voltage appears, and then the AC / DC switch 53 is switched to the AC voltmeter 51 side and the DC voltmeter 52 side. One of the voltmeters swings to measure the voltage value.

Next, the indicator light switch 62 is turned ON. As a result, the indicator light 61 is turned on, and if the lighting state is continued, it is determined that the cause of the residual voltage is an actual voltage due to contact of wiring or the like.
In this case, the actual voltage that causes the voltage may be DC or AC.

On the other hand, as a result of turning on the indicator light switch 62, if the indicator light 61 is lit once, then gradually darkens and then goes out at the end, the cause of the residual voltage is the capacitance in the circuit. Is determined to be.

However, if the indicator light 61 does not turn on even if the indicator light switch 62 is turned on, or if the indication of the AC voltmeter 51 becomes zero, it is determined that the cause of the residual voltage is induction.

According to the above procedure, the cause of the residual voltage can be accurately determined by a series of operations.

Next, a second embodiment of the portable residual voltage discriminator according to the present invention will be described with reference to FIGS.
FIG. 3 is a front view of the discriminator, and FIG. 4 shows a circuit configuration of the discriminator.

As is apparent from comparison with the first embodiment shown in FIG. 1, a clip 30 for detecting a residual voltage can be inserted in place of the pickup 20. Has a rapid deceleration switch 7
3 is additionally provided. Fig. 4 shows the circuit configuration.
However, as is clear from the comparison with the circuit configuration of the first embodiment shown in FIG. 2, the clip 30 is provided instead of the pickup, and the clip 30 is connected in series with the quick attenuation switch 73. Parallel connected resistors 71 and 72
In that a rapid decay circuit 70 is provided. It is preferable to use an enamel resistor having a stable resistance value for the resistors 71 and 72 of the rapid decay circuit 70.

The procedure for determining the cause of the residual voltage using the portable residual voltage determiner 100 is the same as the first embodiment except that the clip 30 is used instead of the pickup 20 to detect the residual voltage. The description is omitted because it is exactly the same as the case of FIG.

If it is determined through the above procedure that the cause of the residual voltage is the capacitance or induction of the circuit, the rapid decay switch 73 of the rapid decay circuit 70 is turned on and the electric charge stored in the capacitance is turned on. Alternatively, the voltage generated by induction is rapidly consumed or attenuated by the resistors 71 and 72. As a result, the indicator light 61 of the voltage attenuation display circuit 60
Is turned off in a short time, so that the time required for determination can be shortened even when the electric charge stored in the capacitance is large. Since the voltage between the connected parts can be reduced to zero, the subsequent operation of measuring the contact resistance of the relay can be performed safely.
An enamel resistor having a stable resistance value is used for the resistor 72. Since the resistors 71 and 72 having known resistance values and the contact resistance of the relay are connected in parallel, a tester or the like is used. Thus, the unknown resistance value of the relay contact can be accurately determined. In such a case, since the conductive portion can be held between the clips 30, the usability is better than that of the pickup.

[0025]

As described above, according to the present invention, when a voltage remains in an electric circuit even after the power is turned off, the cause of the residual voltage is determined by a simple operation. , "Those caused by capacitance in the circuit"
Or "whether due to external guidance" can be determined.

In addition, the following effects can be obtained. (1) It is not necessary to manufacture a temporary circuit or the like, which is conventionally required each time. (2) The time required to determine the cause of the residual voltage can be greatly reduced. (3) Work safety has improved. (4) The built-in rapid decay circuit allows the voltage to be continuously reduced to zero in the case of rapid discharge or induction of capacitance. Will be able to do it. (5) It is suitable for a portable type because of its small size and light weight. (6) Operation is easy. (7) The production cost is low. (8) The state of attenuation of the residual voltage can be checked at a glance. (9) In the investigation of the contact resistance of the relay of the circuit, the unknown resistance can be easily found in a no-voltage state by dividing the current from the known resistance.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of a portable residual voltage discriminator according to the present invention.

FIG. 2 shows a circuit configuration of the portable residual voltage discriminator shown in FIG.

FIG. 3 is a plan view of another embodiment of the portable residual voltage discriminator according to the present invention.

FIG. 4 shows a circuit configuration of the portable residual voltage discriminator shown in FIG.

FIG. 5 is a perspective view of a voltage checking tester.

FIG. 6 is a perspective view of a temporary circuit for determining a voltage.

FIG. 7 is a perspective view of a temporary circuit for continuous voltage discharge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 Pickup 30 Clip 40 Protection circuit 41 Fuse 50 Voltage discriminating circuit 51 AC voltmeter 52 DC voltmeter 53 AC / DC changeover switch 60 Voltage attenuation display circuit 61 Indicator light 62 Indicator light switch 70 Rapid attenuation circuit 71 Resistor 72 Resistor 73 Rapid attenuation switch 100 Portable residual voltage detector

Claims (6)

[Claims] 1. A portable residual voltage discriminator having a pair of residual voltage detecting terminals, wherein a switching type AC / DC voltage discriminating means and an indicator lamp are connected in parallel between the terminals. 2. The portable residual voltage discriminator according to claim 1, wherein an indicator switch that can be manually operated is connected in series with said indicator. 3. A portable device having a pair of residual voltage detecting terminals, wherein a switching type AC / DC voltage discriminating means, an indicator lamp, and a rapid decay element are connected in parallel between the terminals. Type residual voltage classifier. 4. The portable residual voltage discriminator according to claim 3, wherein said quick decay element is a resistor. 5. The portable residual voltage discriminator according to claim 3, wherein said pair of residual voltage detecting terminals are clips. 6. The switch according to claim 3, wherein a manually operable indicator light switch is connected in series with said indicator light, and a manually operable switch is connected in series with said rapid decay element. Portable residual voltage discriminator according to the item.