Abstract: Electric cabinets usually use economical and simple filter fans (also known as fans and filters) to ventilate and dissipate heat due to heat generation. However, during operation, a large amount of dust is found in the cabinet, damaging electrical and electronic devices, and there are potential safety hazards in severe cases. This article introduces a smart ventilation and dustproof solution with good ventilation and heat dissipation, which solves the problem of poor dustproofness when conventional filter fans are ventilated, and at the same time improves intelligent maintenance management.

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As we all know, the dust in the cabinet is the killer of the stable operation of electrical devices such as controllers (such as PLC, DCS, etc.), power electronic devices (such as inverters, servos, filtering, and intermediate frequency, etc.), power supplies, and switches. They are clearly equipped for ventilation and dust filtering. Why does the filter fan accumulate so much dust and cause various inexplicable failures? Let's break it apart to talk about the dustproof and waterproof of the electric cabinet!

1. What is the dustproof effect of the IP5X filter fan?

It is generally believed that installing an IP5X filter fan in an IP5X electrical cabinet can prevent dust from entering the electrical cabinet. What is the actual situation?

In fact, it cannot effectively prevent dust from entering the electrical cabinet. After operation, dust will continue to enter the electrical cabinet. Figure 1 is the IP5X air inlet filter window installed on the electrical cabinet. The dust has made the filter cotton black. Figure 2 is the installation of IP5X filter fan. Dust accumulated on the device in the electric cabinet of the wind window.

Figure 1 & Figure 2.png

2. The dustproof level of the ventilation and dust filtering device that should be configured in the IP5X electric cabinet

2.1 Definition of dustproof level

According to the standard GB_T 4208-2017 shell protection level, IP5X is dustproof, that is, it cannot completely prevent dust from entering, IP6X is dusty and no dust enters.

Figure 3 Dust level code.png

2.2 IP5X and IP6X dustproof test method

Article 13.4 of the standard stipulates that the test methods for the two types of enclosures for dustproof 5 and 6 are as follows, see Figure 4 for details.

1) The first type of shell: the air pressure in the shell is lower than the surrounding atmospheric pressure during the working cycle, for example, due to the thermal cycle effect (that is, there is ventilation and heat dissipation inside and outside the electrical cabinet).

It should be tested according to the dust-proof 6 standard, that is, the vacuum pumping method is used to simulate the thermal cycle effect of the electric cabinet. In the case of a pressure difference of less than 2kPa inside and outside the shell, it needs to be pumped quickly for 2 hours or at low speed for 8 hours;

2) The second type of shell: the air pressure in the shell is the same as the surrounding atmospheric pressure, that is, the static operation without ventilation and heat dissipation inside and outside the electric cabinet.

It should be tested in accordance with dustproof 5, i.e. to simulate no thermal cycle effect, and not connected to the vacuum pump, the test lasts for 8 hours

Figure 4 Dust test method.png

2.3 Dustproof conditions of electric cabinet

1) The dustproof rating of the electric cabinet itself ≧ IP5X;

2) The dustproof level of the ventilation and heat dissipation device must reach IP6X, not IP5X. Reasons:

According to the standard GB_T4208-2017 shell protection level,

2.1) For electrical cabinets that require ventilation and heat dissipation (that is, thermal cycle effects), the ventilation and heat dissipation device needs to reach the IP6X dustproof level, which is the first type of enclosure described in Article 13.4 of the standard.

Reason: Ventilation and heat dissipation devices, such as filter fans, generate pressure during operation, as well as internal and external air circulation;

2.2) The standard 13.5.1 (Figure 5 IP5X electric cabinet test conditions to be used) specifies the test conditions of the IP5X electric cabinet:

In addition to the relevant product standards, the shell is the second type, the shell is regarded as the first type,

Even if there are no special regulations, the dust-proof test of the IP5X enclosure should be tested according to the first enclosure test method (ie IP6X) specified in Article 13.4 of the standard.

Figure 5 Test conditions to be adopted for IP5X electric cabinet.png

2.4 Conclusion

1) According to the standard GB_T4208-2017 enclosure protection level, the heat dissipating IP5X electrical cabinet enclosure (because it is a thermal cycle effect electrical cabinet) should be equipped with an IP6X filter fan.

The IP6X dust-proof test results (see video) have verified the correctness of the standard

2) The ventilation and heat dissipation electric cabinet equipped with the IP5X filter fan is the key reason for the continuous entry, accumulation and hidden dangers of the dust in the IP5X electric cabinet.

3 Cause analysis and solution of the dust in the electric cabinet

3.1 Analysis of the causes of ash ingress

The electric cabinet is usually equipped with an IP5X filter fan, which is static and dustproof, but when the fan is running and ventilated (that is, the electric cabinet has internal and external thermal circulation effects), according to the standard (GB-T4208 enclosure protection level), it should meet the IP6X dust-tight standard But IP5X filter fans often fail to meet IP6X dust standard

The reason is: when the fan runs to form wind pressure, the filter material is deformed, and the pores and gaps increase, so it is not dustproof.

This is the root cause of various electrical cabinets equipped with IP5X filter fans, and a large amount of dust, which causes various failures of PLC, DCS and other controllers, and inverters and servo drives.

3.2 Solution

1) The dustproof of the electric cabinet shell should meet ≧ IP5X;

2) The dustproof level of the filter fan should reach IP6X, and the best waterproof for outdoor applications also reaches IPX5

The IP6X filter fan, with its excellent structural design, ensures that the filter material is resistant to wind pressure, is not deformed, has no gaps and abnormal pores, and achieves static and dynamic dust protection.

4 What is the ventilation efficiency of the IP6X filter fan?

The structure design of the IP6X filter fan ensures that the filter material does not increase pores and open gaps. At the same time, the filter material itself has low wind resistance, so the ventilation efficiency does not decrease, and it is also dust-proof.

Both IP6X and IP5X filter fans have been tested for wind tunnel ventilation. The test shows that:

Ventilation efficiency of IP6X filter fan ≧ Ventilation efficiency of IP5X filter fan Figure 6 & Figure 7.png

5 How to deal with the accumulation of dust in the filter material, which leads to the reduction of the heat dissipation effect?

During the operation of electrical equipment, continuous ventilation and heat dissipation, dust also naturally accumulates on the filter material and causes blockage, and the heat dissipation effect continues to decay. This is the key reason for the initial good heat dissipation of the electrical equipment and the gradual internal overtemperature!

Intelligent ventilation and dust control

Nesputt intelligent fan controller and IP6X filter fan and wind window form an intelligent ventilation and dustproof environmental control solution, which is committed to the full cycle temperature control, dustproof and dehumidification of the electric cabinet microenvironment, and its intelligent management function can be good and the price Solve the problem of heat dissipation attenuation!

Figure 8.png

Features:

1) Temperature, humidity and dust closed-loop detection to provide fan start and stop control, intelligent management parameters and dehumidification parameters;

2) Self-cleaning control, the controller analyzes the binary relationship data of temperature and dust concentration, the fan controller issues instructions, and the IP6X filter fan automatically cleans the filter material dust, which is a good solution to the problem of heat attenuation caused by dust clogging Maintenance costs (Note: IP5X does not support automatic dust cleaning because the pores and gaps formed by wind pressure are too large).

3) Smart filter replacement prompt, the controller draws the conclusion of filter replacement according to the binary relationship data of temperature and dust concentration, promptly prompts to replace the filter, to avoid over-temperature and dust ingress

4) Intelligent management, configure communication interface to make up for the gap of micro-environment management of electric cabinets at the field level

Advantage:

1) Patented products and excellent structural design;

2) High cost performance, excellent price, easy to use and maintain

6 Actual case effect

Dust-proof transformation of an electric vehicle charging station: location, an industrial park; charging power of rectifier cabinet, 120KW

1) Before transformation

Dust condition of charging station rectifier cabinet

Comparison before transformation.png

2) The transformation is completed

Figure 2 Smart fan controller and installation.png Figure 3 IP65 filter fan and installation.png

3) After transformation

In operation for nearly half a year, compared with the unmodified rectifier cabinet

Comparison between the inlet side and the rectifier cabinet

Figure 4 Figure 5.png4) Effect

The dustproof effect is remarkable;

The ventilation and heat dissipation effect is good, the equipment is running without abnormal temperature rise