JPH0814594B2 - Electrolytic capacitor failure determination circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field of the invention
Electrolytic capacitor failure determination circuit that determines whether the polarity of the electrolytic capacitor held in the continuous processing device is in the normal direction, and determines whether there is a short circuit between the anode and the cathode or a short circuit between the anode and the case. It is about.

2. Description of the Related Art In an electrolytic capacitor having polarity, the current flowing between the anode terminal and the cathode terminal has a large difference between when the electrolytic capacitor is connected in the forward direction and when connected in the reverse direction with respect to the DC power supply. . That is, when connected in the forward direction, a large current flows immediately after energization, but then gradually decreases and becomes a minute current after a few seconds. When connected in the opposite direction, a large current flows immediately after energization and does not decrease thereafter, and the large current continues.

Therefore, the polarity determination and the short-circuit defect determination of the conventional electrolytic capacitor are performed by utilizing this characteristic.

That is, the amount of current flowing to the electrolytic capacitor after a certain period of time after being applied to the voltage is determined to determine whether the polarity of the electrolytic capacitor is normal or whether there is a short circuit defect.

However, when the rated voltage and capacitance of the electrolytic capacitor change, the amount of current flowing also changes greatly depending on the applied voltage.Therefore, in order to judge by this method, the current value that is always judged as the applied voltage should be set to the optimum value. There was a troublesome thing to adjust so that Also, with this method,
Since it is necessary to continue applying the voltage until it is possible to determine whether or not there is a defect, there is a drawback that the determination time becomes long and the accuracy is low.

To improve such a defect, as shown in FIG. 5, the potential between the terminal of the electrolytic capacitor 21 and the midpoint of the DC power supplies 22 and 23 properly connected to the terminal and the case of the electrolytic capacitor is detected. A method for discriminating the polarity of an electrolytic capacitor has been proposed. (Japanese Patent Laid-Open No. 60-262416) Problems to be Solved by the Invention The conventional polarity determination circuit as described above has the following problems. That is, two inspection power supplies having the same voltage are required.

During inspection, when the terminal or one of the contact terminals causes a contact failure for some reason, it may be erroneously determined to be normal even if the polarity is reversed.

The present invention is to solve such a conventional problem, irrespective of the rated voltage and the size of the capacitance of the electrolytic capacitor, quickly and accurately determine the polarity and short-circuit failure, and The purpose of the present invention is to determine a defect of an electrolytic capacitor that does not make an erroneous determination even when one contact terminal causes a contact failure at the time of inspection with one inspection power source.

Means for Solving the Problems In order to solve this problem, the present invention relates to a contactor which makes electrical contact with each of an anode terminal, a cathode terminal and a case of an electrolytic capacitor, and contacts on the anode terminal side and the cathode terminal side. And a voltage dividing circuit composed of two resistors connected so as to form a closed circuit, a middle point of the resistance of the voltage dividing circuit, and the case side contactor, which are connected via a switch means, and A DC power source with the negative side connected to the case side contactor,
A comparator for comparing the voltage obtained from the voltage dividing circuit with a reference voltage, and an A / D converter for judging the output signal of the comparator are provided, and the switch means is turned on and off at predetermined intervals. The output signal of the comparator is discriminated by the A / D converter in synchronism with the operation of the switch means so as to discriminate the defective electrolytic capacitor.

Operation With this configuration, a voltage difference is output from one DC power supply to the electrolytic capacitor through the two voltage dividing resistors to the anode lead wire and the cathode lead wire, respectively, and the voltage is output across the two voltage dividing resistors. The DC power supply is 1
Since it is sufficient to detect the output voltage after a short time has elapsed after applying the voltage, a long charging time is not required, and the defect determination can be accurately performed in a short time. or,
Even if the rated voltage or capacitance of the electrolytic capacitor to be inspected changes, it is possible to adjust the magnitude of the applied voltage and the set current value each time. It is not necessary and the defect determination work can be performed easily. Moreover, the switch means and the A / D converter that works in synchronism with it make it possible to erroneously determine that there is an abnormality such as reverse pole connection due to a contact failure of the contact that is likely to occur during inspection. Can be eliminated. That is, when the electrolytic capacitor is charged by the closed loop for a certain period of time when the switch means is turned ON, and then the switch means is turned OFF for a short time, the output voltage of the comparator at that time forms a discharge circuit if the output voltage is securely connected. Therefore, the voltage immediately before is held, but in the case of poor contact, the voltage instantly becomes zero because the discharge circuit is not formed. By discriminating the output voltage by the A / D converter using the clock pulse synchronized with the switch means OFF, it is possible to discriminate correctly whether or not there is a contact failure of the contactor.

EXAMPLE FIG. 1 and FIG. 2 respectively show the configuration and operation of an example of the present invention, in which 1 is an electrolytic capacitor, 2 is an anode lead wire, 3 is a cathode lead wire, 4 is a case, and 5 is a case. Anode contact, 6 cathode contact, 7 case contact, 8
Is a DC power supply, 9 is a switch means that is turned on and off at regular time intervals, and 10 and 11 are resistors forming a voltage dividing circuit.
At the same time as the inspection voltage supply source, it also serves as a detection output voltage supply source. The DC power source 8 side is the case side contactor 7
Through the switch means 9, the two voltage dividing resistors 10 and 11, the anode side contactor 5 and the cathode side contactor 6 to the anode lead wire 2 and the cathode lead wire 3, respectively. They are connected to form a closed loop.

Reference numeral 12 is a comparator for judging the output voltage from the voltage dividing circuit, and 13 is a power supply for supplying a reference voltage necessary for the judgment of the comparator 12, which gives the comparator 12 a low + voltage as the reference voltage. 14
Is an A / D converter circuit for A / D converting the output voltage from the comparator 12, and has a function of making a determination in synchronization with the ON-OFF signal of the switch means 9.

The operation of the present embodiment configured as described above will be described with reference to FIG. 2. (In the case of positive electrode connection) As shown in FIG.
In the case of the positive electrode connection in which the cathode side contactor 6 is connected to the cathode lead wire 3, the voltage dividing resistors 10 and 11 while the switch means 9 is ON.
The electrolytic capacitor 1 is charged through the cathode lead wire 3
The case 4 and the case 4 have the same electric potential, and the cathode lead 3
Since the side is grounded, the voltage at point a is output. When the switch means 9 is turned off after a certain period of time, the electric charge charged in the electrolytic capacitor is discharged through the voltage dividing resistors 10 and 11. However, if the off time is short at this time, the point a is +.
Voltage is maintained. When the comparator 12 determines the voltage at the point a, it becomes the voltage at the point b. Further, the A / D converter 14 determines by the clock pulse c synchronized with the timing when the switch means 9 is OFF, and the final output at the point d. The voltage can be obtained.

(In case of reverse polarity connection) As shown in FIG. 3, the anode side contact 5 is connected to the cathode lead wire 3,
In the case of reverse polarity connection in which the cathode side contactor 6 is connected to the anode lead wire 2, while the switch means 9 is ON, the electrolytic capacitor 1 is charged through the voltage dividing resistors 10 and 11 as in the positive polarity connection. In this case, since the anode lead wire 2 side is grounded, the voltage at point a is output. When the switch means 9 is turned off for a short period of time after a certain period of time, the voltage is discharged through the voltage dividing resistors 10 and 11 as in the positive connection, and the voltage at point a is maintained. At this time, the output voltage of the comparator 12 at the point b and the output voltage of the A / D converter 14 at the point d are voltages in the opposite directions when the positive connection is made, and it can be determined that there is a defect.

(In the case of reverse polarity connection and one side connection) A typical example of a case where an erroneous determination is made due to a contact failure of a contact will be described. As shown in FIG. When contact failure is caused for some reason, and the switch means 9 is turned on by connecting only the cathode side contactor 6 and the anode lead wire 2 and a voltage is applied, the voltage at the point a is output, as if it were the same as the positive connection. Although the state is shown, when the switch means 9 is turned off for a short time after a certain period of time, the voltage at the point a instantly becomes zero potential because the discharge circuit by the voltage dividing resistors 10 and 11 is not formed, and the output of the comparator 12 at the point b. The voltage and the output voltage of the A / D converter 14 at the point d are voltages in the opposite direction when the positive connection is made, and it can be determined that there is a defect.

(In case of short circuit failure) When the electrolytic capacitor 1 has a short circuit failure, the anode side contact 5 and the cathode side contact 6 have the same potential regardless of whether the positive electrode connection or the reverse electrode connection is made. It becomes zero potential, the output voltage of the comparator 12 at the point b and the A / D converter 1 at the point d.
The output voltage of 4 is the voltage in the opposite direction to the case of positive connection, and it can be determined that there is a defect.

In this way, by detecting the direction of the final output voltage of the A / D converter 14 at the point d, whether the polarity of the electrolytic capacitor is normal or short-circuited without erroneous determination due to contact failure, Can be correctly identified.

EFFECTS OF THE INVENTION According to the present invention, in the process of assembling and completing an electrolytic capacitor, it is determined whether the polarity of the electrolytic capacitor held in the continuous processing device is normal, or there is a short circuit between the anode and the cathode. A short circuit between the anode and the case can be accurately determined in a short time with one DC power supply. Further, even if the rated voltage or the electrostatic capacity of the electrolytic capacitor to be inspected changes, the complicated operation of changing the applied voltage or the magnitude of the set current value is not required, and the defect determination can be easily performed. Moreover, switch means and A / D that works in synchronization with this
With the converter, it is possible to eliminate erroneous determination caused by poor contact of the contactor which is likely to occur during inspection.

[Brief description of drawings]

FIG. 1 is a circuit diagram when an electrolytic capacitor is connected to a positive electrode in a circuit configuration according to an embodiment of the present invention, FIG. 2 is a characteristic diagram for explaining the operation of the present invention, and FIG. 3 is a reverse electrode of an electrolytic capacitor. 4 is a circuit diagram in the case where the electrolytic capacitor is connected to the opposite pole and only the anode lead wire is connected, and FIG. 5 is a circuit diagram for determining the polarity of the conventional electrolytic capacitor. . 1 ... Electrolytic capacitor, 2 ... Anode lead wire, 3 ... Cathode lead wire, 4 ... Case, 8 ... DC power supply, 9 ... Switch means, 12 ... Comparator, 14 ... A / D conversion vessel.

Claims (1)

[Claims] 1. A contact for making electrical contact with each of an anode terminal, a cathode terminal and a case of an electrolytic capacitor, a contact for the anode terminal side and a contact for the cathode terminal side, and two contactors connected so as to form a closed circuit. A voltage dividing circuit consisting of a resistor, a DC power source connected between the intermediate point of the resistance of the voltage dividing circuit and the case-side contactor through a switch means, and a negative side connected to the case-side contactor; A comparator for comparing the voltage obtained from the voltage dividing circuit with a reference voltage, and an A / D converter for judging the output signal of the comparator, and for turning on / off the switch means at a predetermined interval. And the output signal of the comparator is synchronized with the operation of the switch means to A / D
A failure determination circuit for an electrolytic capacitor, which performs failure determination of an electrolytic capacitor by determining with a converter.