The Working Environment Requirements of Industrial Frequency Drive

In the actual application of frequency converters, except for a few customers who have dedicated machine rooms, most of them install the frequency converters directly in the industrial site to reduce costs. The working site is usually dusty, hot, and in some places, there is also the problem of high humidity. Besides, in the cable industry, there is metal dust; in the ceramic and dyeing industries, there are corrosive gases and dust; in coal mines and other places, there are also explosion-proof requirements, etc. Therefore, corresponding measures must be taken based on the site conditions.

1. Basic Drive Installation Requirements

(1) The frequency converter should be installed inside the control cabinet.

(2) It is preferable to install the frequency drive in the middle of the control cabinet; the frequency converter should be installed vertically, and the areas directly above and below it should avoid installing large components that may block the air flow in and out.

(3) The minimum spacing between the upper/lower edges of the frequency converter and the top, bottom, or partition of the control cabinet, or the necessary large components, etc., should be greater than 300mm.

(4) If special users need to remove the keyboard during use, the keyboard holes on the frequency converter panel must be strictly sealed with tape or replaced with a fake panel to prevent a large amount of dust from entering the frequency drive interior.

(5) Regular maintenance of the frequency converter is required, and the internal dust and other substances should be cleaned in time.

(6) Other basic installation and usage requirements must comply with the relevant instructions in the user manual; if there are any questions, please contact the corresponding manufacturer's technical support personnel in time.

2. Design Requirements for Dust-proof Control Cabinets

When using frequency converters in dusty environments, especially in places with metal dust and flocculent substances, it is essential to take appropriate and reasonable protective measures. Proper dust-proof measures are crucial for ensuring the normal operation of the frequency converter. The overall requirement for the control cabinet is that it should be sealed and ventilated through specially designed air inlets and outlets; There should be a protective net and a protective cover at the top of the control cabinet for the outlets; There should be a base plate and air inlets, inlet holes at the bottom of the control cabinet, and a dust-proof net should be installed.

(1) The air duct of the control cabinet should be designed reasonably and the exhaust should be smooth to avoid the formation of vortices in the cabinet and the accumulation of dust at fixed positions.

(2) A protective cover should be installed above the outlet on the top of the control cabinet to prevent debris from falling directly; the height of the protective cover should be reasonable and not affect the exhaust. Protective net should be installed at the side outlets of the protective cover to prevent flocculent debris from falling directly.

(3) If the exhaust is from the side of the control cabinet top, a protective net should be installed at the outlet.

(4) It is necessary to ensure that the axial flow fan on the top of the control cabinet rotates in the correct direction, extracting air outward. If the fan is installed outside the control cabinet top, there must be sufficient height between the protective cover and the fan; if the fan is installed inside the control cabinet top, the required screws for installation must use a reverse spring pin to prevent the fan from falling and causing damage to the internal components and equipment. It is recommended to install plastic or rubber vibration-damping gaskets between the fan and the cabinet to significantly reduce the noise caused by the vibration of the fan.

(5) The front and rear doors of the control cabinet and other joints should be sealed with sealing gaskets or sealant to prevent dust from entering.

(6) All air inlets, inlet holes on the bottom and side plates of the control cabinet should be equipped with dust-proof nets. They should block flocculent debris from entering. The dust-proof nets should be designed as detachable to facilitate cleaning and maintenance. The mesh of the dust-proof net should be small enough to effectively block fine flocculent substances (similar to the mesh of common household mosquito and fly screens); Or the appropriate mesh size should be determined according to specific circumstances. The joints around the dust-proof net with the control cabinet should be treated tightly.

(7) The control cabinet must be maintained regularly to remove internal and external dust, flocculent substances, and other debris. The maintenance cycle can be determined according to specific circumstances, but it should be less than 2-3 months; for places with severe dust, it is recommended that the maintenance cycle be around 1 month.

3. Design Requirements for Moisture-proof and Mold-proof Control Cabinets

Most manufacturers of frequency drives do not perform special treatment for moisture-proof and mold-proof on their circuit boards and metal structural components. If the frequency converter remains in this state for a long time, the metal structural components are prone to rusting. For the conductive copper strips operating under high temperatures, the rusting process is exacerbated. For the fine copper wires on the microcomputer control board and drive power board, rusting will cause damage. Therefore, for applications in humid and environments containing corrosive gases, there must be basic requirements for the internal design of the frequency converter. For example, the circuit board must be sprayed with anti-corrosion paint, and the structural components must adopt essential processes such as nickel-chromium plating. In addition, other proactive, effective and reasonable measures for moisture-proof and anti-corrosion gas prevention must also be taken.

(1) The control cabinet can be installed in a separate, enclosed room with air conditioning. This method is applicable when there are many control devices and the cost of establishing a room is lower than the separate enclosed treatment of the cabinet. In such cases, the control cabinet can adopt the dust-proof design mentioned above or a general environment design.

(2) Use an independent air intake. The independent air intake can be placed at the bottom of the control cabinet and connected to the external clean environment through an independent sealed trench. This method requires installing a dust-proof screen at the air intake. If the trench is over 5 meters long, a blower can be considered for installation.

(3) Moisture-absorbing desiccant or active materials that adsorb toxic gases can be added to the sealed control cabinet, and they should be replaced regularly.