Energy saving for energy-saving industrial fans, […]
Energy saving for energy-saving industrial fans, in addition to the design of fan reducers and blades, a suitable inverter is also the key to energy savings. The use of the frequency converter on the industrial fan can meet the process requirements of stepless speed regulation, and it is easy to realize automatic control, and the energy saving can reach more than 20%. Of course, the selection of energy-saving industrial fan inverters also requires certain selection requirements.
1. The motor that the inverter is controlled
The number of poles of the motor, the number of poles of the motor is generally not more than 4, otherwise the speed regulation is not significant. Electromagnetic compatibility, in order to reduce the main power supply interference, add an electric switch in the intermediate circuit or the input circuit of the inverter, or install a front isolation transformer. Generally, when the distance between the motor and the inverter exceeds 50 meters, the reactance should be inserted in the middle. Filters or filters with shielded protective cables.
2. Selection of inverter box structure
The cabinet structure of the frequency converter should be compatible with the conditions. Temperature, humidity, dust, pH, corrosive gas and other factors must be considered. There are several common structures:
Open type: It has no chassis and can be installed in the electric control box or the screen frame in the electrical room. It is especially suitable for use when multiple inverters are used intensively, but the environmental conditions are high. Closed: Suitable for general use, with a small amount of powder or a little humidity. Sealed type: It is suitable for the environment where the industrial site conditions are poor and there are water, dust and certain corrosive gases. When the manufacturer installs the industrial fan, it is necessary to select the appropriate inverter box according to the customer's site conditions.
3, the selection of inverter power
Pay attention to the relationship between the inverter load rate and efficiency. The system efficiency is equal to the product of the inverter efficiency and the motor efficiency. From the efficiency point of view, when selecting the inverter power, pay attention to the following points:
When the inverter power is equivalent to the motor power, it is most suitable to facilitate the inverter to operate under high efficiency. When the power classification of the inverter is different from the motor power classification, the power of the inverter should be as close as possible to the power of the motor and should be slightly larger than the power of the motor. When the motor is frequently started, braking work or heavy load starting and more frequent, a larger frequency converter can be selected to facilitate long-term safe operation of the inverter. After testing, the actual power of the motor does have a surplus. You can consider the inverter with less power than the motor power, but pay attention to whether the instantaneous peak current will cause overcurrent protection. When the inverter and motor power are not the same, the inverter parameter settings must be adjusted accordingly to facilitate high energy saving.
4, the determination of the capacity of the inverter
The selection process of the inverter capacity is actually the best matching process between the inverter and the motor. The most common and safer is to make the capacity of the inverter greater than or equal to the rated power of the motor, but the actual matching should consider the actual motor. The difference between the power and the rated power is usually the capacity of the equipment is too large, but the actual required capacity is small. Therefore, it is reasonable to select the inverter according to the actual power of the motor, avoiding the oversized inverter and increasing the investment. For light loads, the inverter current should generally be selected according to 1.1In (In is the rated motor current), or according to the maximum motor power indicated by the manufacturer in the product matching the output power rating of the inverter.