Why do high voltage ceramic capacitors have poor voltage resistance?

Recently, in the process of new inquiry of our project, a customer asked a question, after the high-voltage capacitor is used on the machine, there is an arc breakdown.

After investigation, the pitch of this high-voltage capacitor is 2000VAC required by the customer

The foot distance is the safety distance, the electrical clearance.

Here, the Porcelain Valley Project will tell you what is the arc pulling, what is the arc breakdown, and under what circumstances the capacitor will have an arc pulling.

Arc pulling refers to a discharge phenomenon when voltage breaks through the air! In electricity, when the voltage between the two conductors breaks through the air layer to form an arc, when the arc is formed, the air will produce a large number of electrons, and the conductivity is rapidly improved.

Arc breakdown, the voltage exceeds the withstand force of the air to ionize the air into a conductor, that is, the arc will generally bypass the insulator along the surface of the insulator, so it will cause damage to the insulator.

For example, the high temperature of the arc can cause the insulator to melt or shatter.

After receiving the product sent by the customer, according to the customer's instructions, three modes of testing and analysis are carried out: 1Core-to-core 2Core to shell 3Shell-to-shell.

The most defective is shell-to-shell.

Based on the accumulated experience of using capacitors for many years, it is suspected that the safety distance is too close.

Let's take a look at the following analysis, haha! I tested the capacity of each product first, and found that the capacity was fine.

Then split the customer offerings.

The voltage is measured in a step-by-step manner, starting from low to high.

When the voltage reaches 2000VAC, the spark magnetoacoustics are generated.

A white halo appeared.

This is the so-called arc pulling.

On closer inspection, it is not difficult to find that the two endpoints that produce the arc are at **.

Conclusion: The poor voltage resistance of high-voltage ceramic capacitors mentioned by the guests is actually a misjudgment caused by arc pulling.

Finally, there is a test to remove the capacitor, and the electrical performance meets the standard.

Arc drawing is not a defective capacitor withstand voltage.

However, the arc will affect the use and judgment.

This is mainly due to the distance between the solder joint and the metal shell is too close to cause arcing.

It is not caused by poor capacitor withstand voltage.

Later, Porcelain Valley Electronic Engineering suggested to the guests that on the solder joints of the PCB board, especially the round solder joints, insulating glue should be added to the points to increase the insulation and prevent the arc between the solder joints and the metal shell.

Porcelain Valley has been focusing on the R&D, production and sales of safety ceramic capacitors for 30 years.

The development of science and technology is inseparable from components, in order to protect the core components from damage, Porcelain Valley Electronics gives you a reassuring choice, providing a strong guarantee for the safety of products!

There are many reasons for this kind of bad pressure, such as your circuit board problems, equipment problems, etc., as well as manual technology problems, you need to find out the cause.

What are the consequences of the high-voltage porcelain capacitor being broken?

First of all, it is excluded that the high-voltage ceramic capacitor will be broken and will not cause personal injury to the user. If it is broken, there will be the following phenomena:

A judgment of Lu: the use of the product is not electrified;

2. Short circuit of the use of the product;

Three: the use of the product invalid.

If a high-voltage ceramic capacitor with poor quality is selected, under the long-term working voltage, the residual bubbles inside will produce partial discharge. Partial discharge further leads to insulation damage and aging. The temperature will also increase, which will cause damage to the capacitance of the high-voltage porcelain and breakdown.

The high-voltage ceramic capacitor on the TV power strip is common to us, and how did we solve the problem of breaking down. Recently, I saw a friend say that the high-voltage porcelain capacitor on his LCD TV was burned out, and the TV had no indicator light, as if there was no electricity. In this case, you can replace the electronic components of this model and check whether the power supply tube has broken down.

Then the high-voltage ceramic capacitor on the power strip is broken, the parameter is 103m 1kv, can it be replaced and replaced.

The answer is yes.

If you choose to replace, then you need to pay attention to:

The difference in capacitance between 30% and 50% of the capacitor will not have a significant effect and can be replaced, but the withstand voltage value must be greater than or equal to the original value. Whichever method you choose, take into account the reality of the power strip as well!

Standardized use will protect the life of the product. In the case that the high-voltage ceramic capacitor is broken and will not be dealt with, you can find a regular high-voltage ceramic capacitor manufacturer for help. When purchasing, it is necessary to choose a manufacturer with guaranteed pre-sales and after-sales service to ensure that it can be used with confidence and avoid unnecessary trouble.

An acidified film is formed at the anode foil of an aluminum electrolytic capacitor, but it can only withstand the continuous application of a specified voltage at the maximum operating temperature. When a voltage above the bearing capacity of the acidified film is applied, the anode foil of the aluminum electrolytic capacitor forms an acidified skin shed equivalent to the applied voltage as a film. The reaction at this point causes the capacitor to produce gas, and the internal pressure rises.

As a characteristic of capacitance, there is a decrease in capacitance and an increase in the positive connection of the loss angle. The amount of gas produced increases with the applied voltage and the temperature around the capacitor. As a result, the internal pressure of the capacitor increases, the sealing material (rubber band) expands, and the safety device starts to activate (the rubber band will fly out if there is no safety device).

The withstand voltage of ceramic capacitors is generally between 25V and 50V.

Porcelain capacitor: It is an electronic component, mainly made of ceramic materials, isolating mesons, which belong to insulators. It is widely used in medium and large electronic equipment and micro-microcontrollers.

Withstand Voltage: is a design nominal value that indicates that this type of capacitor is capable of operating below this voltage for long periods of time. The withstand voltage value is tested by applying a voltage that exceeds this value at both ends of the capacitor.

For example, if a capacitor with a nominal withstand voltage of 200V is applied to 500V for a minute or a few minutes without discharging or bursting, it means that it can work for a long time under a voltage of 200V. The above examples are just hypothetical values, in order to be able to visually understand the withstand voltage parameters, the specific applied voltage depends on the standard of the manufacturer, and it may not be a one-by-one inspection, just a sampling inspection.

The first one is the general ceramic capacitor, the withstand voltage is 25V to 50V, the blue one in the middle should belong to the high-voltage porcelain piece, the withstand voltage is relatively high, and the last one is the CBB capacitor, and the 63 above is the withstand voltage 63V

103 is the cubic of 10x10 and the unit is pfThese numbers are all representations of the capacitance of the capacitance. If there is no standard pressure value, check the specification. Generally, regular ceramic capacitors should have a standard withstand voltage value.

There are also two common ways to mark the withstand voltage of a capacitor, one is to print the withstand voltage value directly on the capacitor, and the other is to use a combination of a number and a letter. The number represents the power exponent of 10, and the letter represents the numeric value in the unit of v (volt).

The letters a, b, c, d, e, f, g, h, j, k, z

The withstand voltage value of 1J represents.

2f stands for. 3a stands for.

1k represents. The maximum number is 4, such as 4z for 90000V

Generally 100 volts is no problem.

The housing is ceramic for insulation, and the voltage is generally greater than 1kv, and the highest I've seen is 30kv.

It is a circular plate capacitor with ceramic material as the medium, in the "porcelain" capacitor, the general DC50V below DC50V is called low voltage, DC100V 500V is medium and high voltage, DC1000V 6000V and high voltage, safety Y capacitor is also high voltage, DC6000V or above is ultra-high voltage.

It is generally used in power supply circuits for high-frequency and high-voltage spike absorption.