JP3791326B2 - Capacitor measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of measuring capacitor.
[0002]
[Prior art]
Conventionally, high-temperature insulation resistance selection and burn-in (aging) have been performed to ensure the reliability of ceramic capacitors. Alternatively, after the withstand voltage measurement, a heat treatment so-called heat return treatment is performed in order to release the polarization of the ceramic capacitor made of the polarized high dielectric constant material (to bring it into a non-polarized state).
[0003]
For example, a conventional ceramic capacitor aging method described in Japanese Patent Application Laid-Open No. 11-97299 performs an aging process in which a voltage is applied under heating as a countermeasure for stabilizing the ceramic capacitor. Therefore, a holding jig for applying a voltage to the ceramic capacitor and a heater for heating the ceramic capacitor are provided in a heating furnace covered with a heat insulating material, and the ceramic capacitor is set in the holding jig in the heating furnace. In addition, the entire interior of the heating furnace including the ceramic capacitor was heated by the heater.
[0004]
[Problems to be solved by the invention]
Therefore, conventional high-temperature insulation resistance sorting and burn-in require the use of a heating furnace in order to heat the ceramic capacitor, and there is a problem that the apparatus becomes large for heating and heat insulation.
[0005]
An object of the present invention is to provide a measuring method of a capacitor can be miniaturized high temperature insulation resistance selection apparatus and the burn-in apparatus, or the like.
[0008]
[Means and Actions for Solving the Problems]
In order to achieve the above object, the method for measuring a capacitor according to the present invention electrically connects a DC power supply to the capacitor via AC cut means, and electrically connects an AC power supply via DC cut means, Using a device having a circuit in which a DC power supply and an AC power supply are connected in parallel to a capacitor, an AC current is applied to the capacitor, the capacitor is self-heated to a predetermined temperature, and a DC current is applied to the capacitor. It is characterized by measuring the leakage current of the direct current while applying it to determine the insulation resistance value of the capacitor. Alternatively, an alternating current is applied to the capacitor to cause the capacitor to self-heat to a predetermined temperature, and after being left for a certain period of time while applying a direct current to the capacitor, the leakage current of the direct current is measured to determine the burn-in of the capacitor. Perform screening.
[0009]
When an alternating current is applied to the capacitor, the capacitor self-heats due to dielectric loss and electrode resistance. Using this self-heating, the capacitor is raised to a predetermined temperature, the leakage current of the capacitor in a high temperature state is measured, and the insulation resistance value is obtained. That is, only the capacitor is heated, and the high-temperature insulation resistance sorting device and the burn-in device are simplified and miniaturized.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
It will be described below with reference to the embodiment the accompanying drawings exemplary method of measuring capacitor according to the present invention.
[0011]
[First Embodiment, FIG. 1]
1st Embodiment demonstrates the manufacturing method of a ceramic capacitor, especially the heat return processing method.
[0012]
The heat return process is a process of heating the ceramic capacitor to a temperature above the Curie point after measuring the withstand voltage and releasing the polarization of the ceramic capacitor made of a polarized high dielectric constant material (to make it unpolarized). This is because a high dielectric constant ceramic material is polarized by a high voltage (DC voltage) applied when measuring the withstand voltage of the capacitor.
[0013]
FIG. 1 shows an electrical circuit for the heat return process. The ceramic capacitor C subjected to the heat return process is sandwiched between the holding terminals 2 and 3. These holding terminals 2 and 3 are electrically connected to the AC power source 1. In the case of the first embodiment, the AC power supply 1 applies a high-frequency current having a frequency of 100 KHz to the ceramic capacitor C. As a result, the ceramic capacitor C self-heats due to dielectric loss, and the ceramic capacitor C is heated to about 150 ° C. Thereafter, the application of the high frequency current is stopped, and the ceramic capacitor C is naturally cooled. Thereby, the heat return process which makes the ceramic capacitor C polarized at the time of withstand voltage measurement into a non-polarization state is performed. As a result, only the ceramic capacitor C is heated, and the heat return processing device can be simplified and miniaturized.
[0014]
[Second Embodiment, FIG. 2]
2nd Embodiment demonstrates the measuring method of the high temperature insulation resistance of a ceramic capacitor.
[0015]
In high-temperature insulation resistance measurement, the temperature and voltage are applied to the capacitor, and the defective part of the capacitor product that has a defect that will become a defective insulation resistance in the future is quickly revealed as an insulation resistance defect by accelerating the temperature and voltage. It is a measurement to be performed.
[0016]
FIG. 2 shows an electric circuit for measuring the high temperature insulation resistance of the ceramic capacitor C. The ceramic capacitor C whose insulation resistance is measured is sandwiched between the holding terminals 2 and 3. These holding terminals 2 and 3 are electrically connected to the AC power source 1. The DC cut decoupling capacitor Cd is for preventing a DC voltage from being applied to the AC power supply 1 side. The AC cut inductor 4 is for preventing an AC current from flowing to the DC power supply 6 side. The DC power source 6 is for applying a DC voltage (64 V in the case of the second embodiment) to the ceramic capacitor C. Further, the leak current detection ammeter 5 is for monitoring the current value of the DC power supply 6 applied to the ceramic capacitor C in order to detect the deterioration of the insulation resistance of the ceramic capacitor C. In the case of the second embodiment, the AC power supply 1 applies a high frequency current having a frequency of 100 KHz and a current value of 2 Arms to the multilayer ceramic capacitor C having a capacitance of 0.1 μF.
[0017]
Thereby, the ceramic capacitor C is self-heated by dielectric loss, and the ceramic capacitor C is heated to about 85 to 150 ° C. (85 ° C. in the case of the second embodiment). In this state, the ammeter 5 measures the direct current value of the direct current power source 6, that is, the leakage current value flowing through the ceramic capacitor C. The insulation resistance value (at 85 ° C.) of the ceramic capacitor C can be calculated from the leakage current value and the DC voltage value (64 V) of the DC power source 6.
[0018]
As a result, the ceramic capacitor C can be brought to a predetermined temperature without using an external heating device such as a heater or a heat insulating material, and the high-temperature insulation resistance selection device can be simplified and miniaturized. Specifically, the size of the apparatus can be reduced to about 2/3 of the conventional size.
[0019]
[Third Embodiment]
In the third embodiment, burn-in screening of ceramic capacitors will be described. In the burn-in screening, similarly to the high-temperature insulation resistance measurement of the second embodiment, the temperature and voltage are applied to the capacitor, and the defective portion of the capacitor product that has a defect that will become a defective insulation resistance in the future is detected by the temperature and voltage. This is a method that is performed in order to make the insulation resistance defect manifest as early as possible by acceleration. The electric circuit for burn-in screening is a circuit similar to that of FIG. 2 of the second embodiment, and thus detailed description thereof is omitted.
[0020]
The AC power supply 1 applies a high frequency current having a frequency of 100 KHz and a current value of 2 Arms to the multilayer ceramic capacitor C having a capacitance of 0.1 μF. As a result, the ceramic capacitor C is self-heated by dielectric loss and heated to about 85 to 150 ° C. (85 ° C. in the case of the third embodiment). In this state, a DC voltage is applied to the ceramic capacitor C by the DC power supply 6 and left for a certain period of time. Then, the application of the high frequency current from the AC power supply 1 and the voltage application from the DC power supply 6 are stopped, and the ceramic capacitor C is Allow to cool. When the temperature of the ceramic capacitor C drops to room temperature, the ammeter 5 measures the direct current of the direct current power source 6, that is, the leakage current flowing through the ceramic capacitor C.
[0021]
The insulation resistance value of the ceramic capacitor C is obtained from the leakage current and the DC voltage value of the DC power source 6, and compared with the insulation resistance value before the burn-in screening, and the degree of deterioration of the insulation resistance of the ceramic capacitor C is detected. Sort out. The leakage current may be measured while the ceramic capacitor C is kept at a high temperature. Thus, the ceramic capacitor C can be brought to a predetermined temperature without using an external heating device such as a heater or a heat insulating material, and the burn-in screening device can be simplified and miniaturized.
[0022]
[Other Embodiments]
In addition, the measuring method of the capacitor | condenser which concerns on this invention is not limited to the said embodiment, It can change variously within the range of the summary. In particular, various electric circuits having a similar AC power supply can be selected for the purpose of self-heating of the capacitor.
[0023]
【The invention's effect】
As is clear from the above description, according to the present invention, since the capacitor is brought to a predetermined temperature by utilizing self-heating when an alternating current is applied to the capacitor , the high-temperature insulation resistance selecting device and the burn-in device are used. Etc. can be simplified and downsized.
[Brief description of the drawings]
FIG. 1 is an electric circuit diagram showing an embodiment of a capacitor manufacturing method according to the present invention.
FIG. 2 is an electric circuit diagram showing one embodiment of a capacitor measuring method according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... AC power supply 2, 3 ... Holding terminal 4 ... AC cutting inductor 5 ... Ammeter 6 ... DC power supply C ... Ceramic capacitor Cd ... DC coupling decoupling capacitor

Claims (2)

A DC power supply is electrically connected to the capacitor via the AC cut means, and an AC power supply is electrically connected via the DC cut means, and the DC power supply and the AC power supply are connected in parallel to the capacitor. Using a device with a circuit that
An alternating current is applied to the capacitor, with the capacitor by self-heating to a predetermined temperature, the determination of the insulation resistance of the capacitor by measuring the leakage current of the DC current while applying a DC current to said capacitor Characteristic capacitor measurement method. A DC power supply is electrically connected to the capacitor via the AC cut means, and an AC power supply is electrically connected via the DC cut means, and the DC power supply and the AC power supply are connected in parallel to the capacitor. Using a device with a circuit that
An alternating current is applied to the capacitor, with the capacitor by self-heating to a predetermined temperature, allowed to stand a certain time while applying a DC current to said capacitor, burn capacitor by measuring the leakage current of the DC current A method for measuring a capacitor, comprising performing screening.

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