JP2697426B2 - Test equipment for electrolytic capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test apparatus for an electrolytic capacitor for simultaneously determining in a short time whether the leakage current of an electrolytic capacitor is good or not, whether or not there is a disconnection, and whether or not there is instantaneous destruction.

[0002]

2. Description of the Related Art Conventionally, in determining the quality of leakage current of an electrolytic capacitor, the value of the current flowing through the capacitor when a specified voltage is applied for a specified time in advance is standardized to obtain a leakage current standard. A measurement reference value circuit that converts a DC current flowing through a capacitor when this specified voltage is applied for a specified time to a DC voltage with a current-to-voltage converter, and that leaks and generates a current specification value as a voltage output corresponding to the DC voltage. And an output of the RS flip-flop is operated by the output of the corresponding "1" or "0" comparator / determiner circuit. The light emitting diode is turned on or off according to the state, thereby determining whether the leakage current is good or not.

On the other hand, when determining the presence or absence of disconnection of an electrolytic capacitor, a specified voltage is applied to the capacitor. Immediately after that, if the electrolytic capacitor under test has no disconnection, an inrush current flows. When the DC voltage is converted by the converter and input to the comparator circuit, the output of the comparator circuit rises rapidly, resetting the first flip-flop previously set.

When a capacitor is discharged after a specified voltage is applied for a specified time, a discharge current flows if the electrolytic capacitor under test has no disconnection. This discharge current is converted into a DC voltage by a current-voltage converter. When input to the comparison / determination circuit, the output of the comparison / determination circuit rapidly rises and resets the second flip-flop that has been set in advance. A set output of the first flip-flop;
The set output of the flip-flop is ORed, and when there is no disconnection, the light emitting diode is turned off.
If the capacitor is disconnected from the beginning, the inrush current does not flow even when the specified voltage is applied, so that the first flip-flop previously set cannot be reset, and the specified voltage is applied for the specified time. Thereafter, when the discharge is performed, since the discharge current does not flow, the previously set second flip-flop cannot be reset, and the light emitting diode is turned on to determine that there is a disconnection. Further, when the capacitor is disconnected during application of the specified voltage, an inrush current flows, so that the previously set first flip-flop is reset. Since no current flows, the previously set second flip-flop cannot be reset, the light emitting diode is turned on, and it is determined that there is a disconnection (Japanese Patent Application No. 60-277755).
issue).

[0005]

In this conventional device,
After applying the specified voltage to the capacitor under test for the specified time, the quality of the leakage current flowing through the capacitor is determined.Therefore, insulation breakdown occurred inside the capacitor while the specified voltage was applied to the capacitor for the specified time. In this case, there is a problem that a phenomenon in which the dielectric breakdown is repaired instantaneously by the self-healing action (generally, instantaneous breakdown) cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides an electrolytic capacitor testing apparatus capable of simultaneously determining the presence or absence of instantaneous destruction in addition to the determination of leakage current and disconnection of an electrolytic capacitor. The purpose is to provide.

[0007]

An electrolytic capacitor testing apparatus according to the present invention comprises a connecting terminal of an electrolytic capacitor to be tested;
A circuit for applying a test voltage to one of the connection terminals, a current-to-voltage converter for converting the other current of this connection terminal to a voltage, and a first for comparing the output of the current-to-voltage converter with a first reference voltage , A first flip-flop set by the output of the comparison circuit, a second flip-flop reset by the output of the comparison circuit, and a second flip-flop illuminated by the set output of the first flip-flop. 1 light emitting diode, a second light emitting diode that is turned on by the set output of the second flip-flop,
A second comparison circuit for comparing the output of the current-voltage converter with a second reference voltage having a polarity different from the first reference voltage, and a third flip-flop reset by the output of the second comparison circuit A circuit for ORing together the set output of the third flip-flop and the set output of the second flip-flop to the second light emitting diode, and the output of the current-to-voltage converter to the first A third comparison circuit having the same polarity as that of the third reference voltage and having a different voltage value, a fourth flip-flop set by the output of the third comparison circuit, and a fourth flip-flop. And a third light emitting diode that is turned on by the set output of the lamp. It is preferable that n (plural) electrolytic capacitor testing devices be arranged in parallel.

[0008]

In the present invention, when instantaneous destruction occurs in the electrolytic capacitor under test, a short-circuit current flows rapidly, and the output of the current-voltage converter exceeds the short-circuit current standard (third reference voltage). Thereby, the output of the third comparison circuit is, for example, “1”.
And "1" is set to the set terminal of the fourth flip-flop.
Is input, and the fourth flip-flop is set.
Therefore, the third light emitting diode is turned on, and the occurrence of instantaneous destruction can be detected.

[0009]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an electrolytic capacitor test apparatus according to an embodiment of the present invention, and FIG. 2 is a time chart for operating the test apparatus of FIG.

In FIG. 1, the positive potential side of a DC measuring power supply (E1) 1 is connected to relay contacts 3-1, 3 and 3n of a relay 2 driven by a charging time signal TIM1, and further to a discharging time signal TIM3. Relay contact 5 ・ 1 of relay 4 to be driven
Through the electrolytic capacitors 6-1 through 6-n
, Respectively. Charge time signal TIM
Relay contacts 3 to 1 to 3n of relay 2 driven by 1
Are connected in parallel with each other and connected to the positive potential side of the DC measurement power supply 1, and the a contacts of the relay contacts 5-1 to 5-n of the relay 4 driven by the discharge time signal TIM3 are all ground terminals. And this ground terminal is connected to the DC measurement power supply 1
Is connected to the negative potential side.

The input terminals of the current-to-voltage converters 8.1-1.n are connected to the cathode sides of the capacitors under test 6.1-1-6-n via the resistors 7.1-1-7.n, respectively. The ground terminals are connected in parallel and are also connected to the negative potential side of the DC power supply 1.

Next, the first comparison / determination circuits 12-1 to 1-1
2 · n signal input terminals are current-voltage converters 8.1 to 8 respectively.
N are connected to the output terminals of n, and all of the reference input terminals are connected in parallel and also connected to the first measurement reference value circuit 9.

Further, the second comparison / determination circuits 13-1 to 13-1
3 · n signal input terminals are connected to the current / voltage converters 8.1 to 1 respectively.
8n, and all the reference input terminals are connected in parallel and connected to the second measurement reference value circuit 10.

Further, the third comparison / determination circuits 14-1 to 14-1
4 · n signal input terminals are current-voltage converters 8.1 to 8 respectively.
N is connected to the output terminal of n, and all of the reference input terminals are connected in parallel and connected to the third measurement reference value circuit 11.

The first RS flip-flop 20a.1
The set terminals of .about.20a.n are connected to the output terminals of the first comparator / determiner circuits 12.1-12.n, respectively, and the reset terminals are connected to the output terminals of the two-input OR circuits 15a.about.1-15a.n. Connected, two-input OR circuits 15a-1 to 15-15
a and n are connected in parallel, and
6 to the reset signal SIG1.

The other input terminal is connected in parallel and connected to the hold signal SIG3 of the first flip-flop 20a.i via the terminal 18, and the Q terminal is connected to each of the inverter circuits 21a.1-2a. N and then connected to the cathodes of the light emitting diodes 23a.1 to 23a.n via the resistors 22a.1 to 22a.n. The anode of this light-emitting diode is connected in parallel and the relay contact 2 of the relay 24 activated by the power-on signal TIM2 of 23a.i, 23b.i and 23ci.
5 is connected to the positive potential side of a light emitting diode driving power supply (E2) 26.

The second RS flip-flop 20b-1
The reset terminals of .about.20b.n are connected to the output terminals of the first comparator / determiner circuits 12.1-1.n, respectively, and the set terminals are connected to the output terminals of the two-input OR circuits 15b.about.1-15b.n. And these two-input OR circuits 15b-1 to 15-1
One of the input terminals of 5b · n is connected in parallel and connected to a reset signal SIG1 via a terminal 16, and the other input terminal is connected in parallel and connected to a set signal SIG2 via a terminal 17. Is done.

The third RS flip-flop 20c-1
The reset terminals of .about.20 c.n are respectively connected to the output terminals of the second comparison / determination circuits 13.1-1.n, and the set terminals are connected to the output terminals of the two-input OR circuits 15c.about.15c.n. And these two-input OR circuits 15c-1 to 15-1
One input terminal of 5c · n is connected in parallel, and is connected to a reset signal SIG1 via a terminal 16. The other input terminal is connected in parallel in the same way.
Connected to the set signal SIG2 via the terminal 17 and connected to the second RS flip-flop 20b-1.
To 20b · n and the Q terminals of the third RS flip-flops 20c · 1 to 20c · n to the input terminals of the two-input OR circuits 15e · 1 to 15en · n, respectively. These two input terminal OR circuits 15e and 1 to 15e
The output terminals of n are inverter circuits 21b.
b · n, and connected to the cathodes of the light emitting diodes 23b · 1 to 23b · n via the resistors 22b · 1 to 22b · n.
The anodes of 23b · n are connected in parallel and connected to the positive potential side of a light emitting diode driving power supply 26 via a relay contact 25 of a relay 24 activated by a power on signal TIM2 of each light emitting diode.

The present embodiment has the following features. That is, the fourth RS flip-flop 20d-1
To 20 d · n are connected to the output terminals of the third comparison / determination circuits 14. 1 to 14 · n, respectively, and the reset terminal is connected to the output terminals of the two-input OR circuits 15 d · 1 to 15 d · n. Connected, two-input OR circuits 15d-1 to 15-15
One of the input terminals d and n is connected in parallel, and
6 is connected to the reset signal SIG1, and the other input terminal is connected in parallel, and the terminal 19 is connected to the hold signal SIG4 of the fourth flip-flop 20d.i.
And the Q terminal is connected to each of the inverter circuits 21c.
.1 to 21c.n are connected, and resistors 22c.1 to 2 are connected.
The light emitting diodes 23c.1 to 23c.
n, and the anodes of the light emitting diodes 23c.1 to 23c.n are connected in parallel, and the light emitting diodes are connected via a relay contact 25 of a relay 24 activated by a power-on signal TIM2 of each light emitting diode. It is connected to the positive potential side of the drive power supply 26.

Next, the operation of this embodiment will be described with reference to FIGS.

Generally, a DC current flowing through a capacitor has a characteristic that it rises sharply at the start of charging and then gradually decreases with time. Current i flowing through this capacitor
(T) is represented by Equation 1 below.

[0023]

## EQU1 ## i (t) = (V / Rs) exp (-t / CRs)
) + Ia (t) + Ie where, V; applied voltage (V) Rs; series insertion resistance (Ω) C; capacitor capacitance ia (t); absorption current Ie; true leakage current.

According to the above equation (1), the true leakage current Ie of the capacitor is a unique constant that is not affected by time, but a long time charging is required to measure this value.

For this reason, the capacitor maker standardizes a specified current value after a certain specified time has elapsed, and sets it as a leakage current standard. Therefore, the leakage current of the electrolytic capacitor may be determined by determining whether the leakage current conforms to the leakage current standard. According to Equation 1, if the DC current i (t) flowing through the capacitor is equal to or less than the leakage current specification after the lapse of the specified time, it is determined to be good.

The first R / S flip-flops 20a.about.20a.n and the fourth RS flip-flops 20d.about.20d.n in FIG. 1 are output by the reset signal SIG1 in FIG. 2 when the system power is turned on. Q is “0” and the second RS flip-flop 20 b.
1 to 20b · n and the third RS flip-flop 20c
The output Q of 1 to 20c · n is “1” by the set signal SIG2 in FIG. At the start of the measurement,
According to the charging time signal TIM1, the relay contacts 3, 1, 3,.
n is closed, and a DC current i (t) flowing through the capacitors to be tested via the electrolytic capacitors 6-1 to 6-n and the resistors 7-1 to 7-n is generated. Current-voltage converters 8.1-8
DC current i (t) flowing to the capacitor at n is converted to DC voltage V (t), and the following equation 2 is obtained.

[0027]

## EQU2 ## i (t) ∝V (t)

Thereafter, the DC current i flowing through the capacitor i
(T) is treated as the DC voltage V (t) obtained by the current-voltage conversion, and the value of the DC current at a certain time t is represented as the DC voltage V (t).

The first measurement reference value circuit 9 is a circuit that can generate a value of the leakage current standard and a voltage output Vref1 corresponding to the DC voltage V (t), and manually set an arbitrary leakage current standard. it can. Therefore, the first comparison / determination circuits 12-1 to 12-1
The output of 12.n is "1" if V (t)> Vref1 in the section T of the charging time TIN1, and is "0" if V (t) <Vref1.

FIG. 3 shows a DC current i flowing through the capacitor.
When V (t) obtained by converting (t) is a non-defective product with respect to a DC voltage (hereinafter referred to as a leak current standard) Vref1 obtained by converting a leak current standard value after a lapse of time T, a relation between respective circuit outputs is obtained. With respect to the time axis. In FIG. 3, the DC current V (t) flowing through the electrolytic capacitor 6.i under test during the specified time interval T first leaks and flows to the current specification Vref1 or more.
The output of the first comparator / determiner circuit is "1", and
The output of the flip-flop 20a · i also becomes “1”, and the state of the light emitting diode 23a · i changes to the light emitting diode 23a.
Power-on signal TIM2 of i, 23b · i, 23c · i
However, before the leakage current is judged, the output of the first comparator / decision circuit becomes "0" before the leakage current is judged. Since the output of the step 20a · i becomes “0”,
The state of the light emitting diodes 23a · i is turned off. Thereafter, this state continues until reset due to the fall of the hold signal SIG3 of the flip-flops 20a and i in FIG.

FIG. 4 shows the relationship between the output of each circuit with respect to the time axis when the DC current flowing through the capacitor leaks and is defective with respect to the current standard.

In this case, the DC current V (t) flowing through the electrolytic capacitor 6.i during the specified time interval T is equal to the leakage current standard Vref1 from the start of measurement to the point of time when the leakage current is judged good or bad.
As described above, the output of the first comparison / determination circuit is “1”.
, The output of the flip-flop 20a · i is also “1”, and the state of the light emitting diodes 23a · i is also a lighting state. Thereafter, the flip-flop 2 of FIG.
The lighting state continues until the reset point due to the fall of the hold signal SIG3 of 0a · i.

Next, a method of determining the presence or absence of a disconnection will be described with reference to FIGS.

The output of the flip-flop 20b.i is shown in FIG.
Is set to “1” immediately after the power is turned on by the set signal SIG2 of the capacitor.
If i is in a state where there is no disconnection, an inrush current flows at that moment, and the output V (t) of the current-voltage converter 8i is expressed by the following equation 3.

[0035]

I = V / Rs∝V (t) where V: applied voltage (V) Rs: series insertion resistance (Ω).

Since the output of the first comparator / judgment circuit rapidly rises by the output V (t) of the equation (3), a reset input is input to the reset terminal of the flip-flop 20b.i, and the output of the flip-flop 20b.i Becomes “0” from that moment.

The output of the flip-flop 20c.i is "1" immediately after the power is turned on by the set SIG2 of FIG. 2, but at the time of the start of discharge shown in FIG.
The relay contact 5.i is connected to the X-7 contact a by M3, and the anode side of the electrolytic capacitor 6.i to be tested is connected to the ground terminal. If no disconnection occurs in 6 · i, a discharge current flows at that moment, and the electrode V of the current-voltage converter 8 · i
(T) is expressed in the same manner as in Expression 3.

The output V (t) rises rapidly, exceeds the discharge current standard Vref2, the output of the second comparator / determiner circuit becomes "1", and the reset input of the reset terminal of the flip-flop 20c.i Therefore, the output of the flip-flop 20c.i becomes "0" from that moment. From the moment when the output of the flip-flop 20b.i becomes "0" and the output of the flip-flop 20.i becomes "0", the state of the light emitting diode 23b.i is turned off and continues until reset.

Next, a case where there is a disconnection will be described with reference to FIG. In this case, the electrolytic capacitor 6 · i to be tested
No current flows through. Therefore, as shown in FIG. 5, the flip-flops 20b.i and the flip-flops 20c.
No reset input is input to the reset terminal of i, and the output maintains the state of “1” from the start of measurement to the reset, and the light emitting diodes 23b · i are the light emitting diodes 23a · i and 23b · i of FIG. , 23c · i, the lighting is started by the power-on signal TIM2, and the lighting is continued until reset.

FIG. 6 shows that the capacitor under test 6.i had no disconnection at the start of the measurement, but the charge time signal TO
It is a timing chart figure about the case where it has disconnected in the section T of M1. In this case, since the electrolytic capacitor 6 • i under test has no disconnection at the start time 1 of the measurement time, an inrush current flows, a reset input enters the reset terminal of the flip-flop 20b • i, and the output of the flip-flop 20b • i Becomes “0” from that moment, but if the disconnection occurs in the section T of the charging time signal TIM1, the reset input is not input to the reset terminal of the flip-flop 20c ・ i, and the output of the flip-flop 20c ・ i Since the state of "1" is kept until the reset, the light emitting diodes 23b.i start lighting by the power-on signal TIM2 of the light emitting diodes 23a.i, 23b.i, and 23c.i in FIG. Continue.

Finally, FIG. 7 shows an electrolytic capacitor 6 under test.
FIG. 6 is a timing chart showing a case where instantaneous destruction occurs in a section T of the charging time signal TIM1. In this case, the electrolytic capacitor 6 i under test instantaneously suffers dielectric breakdown and is short-circuited, so that the DC current rises sharply. Immediately after that, the dielectric breakdown is instantaneously repaired by the self-recovery action. The direct current has a characteristic of gradually decreasing.

Here, at the time of the start of the measurement, the rush current flows to the electrolytic capacitor 6 • i to be tested more than the short-circuit current standard Vref3, and the output of the third comparator / determiner circuit becomes “1”.
Although "1" is input to the set terminal of the flip-flop 20d.i, the output of the flip-flop 20d.i is "D" because the hold signal SIG4 of the flip-flop 20d.i of FIG. 2 is input to the reset terminal. 0 ". Thereafter, when instantaneous destruction occurs in the electrolytic capacitor 6.i under test, a short-circuit current flows rapidly, and the output V (t) of the current / voltage converter exceeds the short-circuit current standard Vref3. The output becomes “1”, and “1” is input to the set terminal of the flip-flop 20d ・ i. At this time, the hold signal S of the flip-flop 20d ・ i
Since IG4 is “0”, flip-flop 2
The output of 0d · i becomes “1”, and the state of the light emitting diode 23c · i is also a lighting state. Thereafter, the lighting state continues until the time of reset.

[0043]

As described above, according to the present invention, it is possible to judge the presence / absence of instantaneous destruction in addition to the judgment of the leakage current and disconnection of the electrolytic capacitor by simultaneously turning on and off the light emitting diode. There is an effect that a high inspection can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a test apparatus for an electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is a time chart of the embodiment shown in FIG. 1;

FIG. 3 is a signal waveform diagram in each section when leakage current is good.

FIG. 4 is a signal waveform diagram in each part when leakage current is defective.

FIG. 5 is a signal waveform diagram in each part in the case of disconnection from the beginning.

FIG. 6 is a signal waveform diagram in each section when a disconnection occurs during a test.

FIG. 7 is a signal waveform diagram in each part in the case of instantaneous destruction during a test.

[Explanation of symbols]

1; DC measurement power supply (E1) 2, 4, 24; relay 3.1 to 3n, 5-1 to 5n, 25; relay contact 6.1 to 6n; electrolytic capacitor to be tested 7.1 ~ 7 · n, 22a · 1 to 22a · n, 22b · 1
22b.n, 22c1 to 22c.n; resistors 8.1 to 8.n; current-voltage converter (CONV) 9; first measurement reference value circuit (REF1) 10; second measurement reference value circuit (REF2) 11) Third measurement reference value circuit (REF3) 12.1 to 12 · n; first comparison / determination circuit 13.1 to 13 · n; second comparison / determination circuit 14.1 to 14 · n A third comparator / determiner circuit 15a-1 to 15a-n, 15b-1 to 15b-n, 1
5c ・ 1 to 15c ・ n, 15d ・ 1 to 15d ・ n, 15
e · 1 to 15e · n; 2-input OR circuit 16; reset signal (SIG1) 17; set signal (SIG2) 18; hold signal (S) of flip-flops 20a · i
IG3) 19; hold signal of flip-flop 20d · i (S
IG4) 22a.1 to 22a.n, 22b.1 to 22b.n, 2
2c.1 to 22c.n, 22d.1 to 22d.n; flip-flops 21a.1 to 21a.n, 21b.1 to 21b.n, 2
1c · 1 to 21c · n; Inverter circuits 23a · 1 to 23a · n, 23b · 1 to 23b · n, 2
3c.1 to 23c.n; light emitting diode 26; driving power supply (E2) for light emitting diode T; specified time section TIM1; charging time signal TIM2;
3c · i power-on signal TIM3; discharge time signal Vref1; leakage current specification Vref2; discharge current specification Vref3; short-circuit current specification

Claims (1)

(57) [Claims] 1. A connection terminal of an electrolytic capacitor under test, a circuit for applying a test voltage to one of the connection terminals, a current-to-voltage converter for converting the other current of the connection terminal into a voltage, and a current-to-voltage converter A first comparing circuit for comparing the output of the comparator with a first reference voltage, a first flip-flop set by the output of the comparing circuit, and a second flip-flop reset by the output of the comparing circuit. A first light-emitting diode that is turned on by the set output of the first flip-flop, a second light-emitting diode that is turned on by the set output of the second flip-flop,
A second comparison circuit for comparing the output of the current-voltage converter with a second reference voltage having a polarity different from the first reference voltage, and a third flip-flop reset by the output of the second comparison circuit A circuit for ORing together the set output of the third flip-flop and the set output of the second flip-flop to the second light emitting diode, and the output of the current-to-voltage converter to the first A third comparison circuit having the same polarity as that of the third reference voltage and having a different voltage value, a fourth flip-flop set by the output of the third comparison circuit, and a fourth flip-flop. A third light-emitting diode that is lit by a set output of a lamp.