How to choose the appropriate frequency converter ( Five skills)

by:V&T Technologies     2020-03-08
Along with the rapid development of industrial automation process, as the inverter frequency conversion debugging also has been widely used. Inverter frequency control of motor speed, energy conservation as an important role, its role is largely by changing the way to control the motor power frequency ac motor power control equipment. Its advantage is not only for the enterprise to improve the level of processing, also energy conservation plays an important role for the enterprise. So how to choose appropriate frequency converter? Frequency converter manufacturers today is to introduce the choose and buy of frequency converter technique. First, select the frequency converter to from what aspects? Choose the type of frequency converter, according to the type of production machinery, speed range, static speed precision, starting torque requirements, decided to choose the control mode of the inverter is the best. So-called is appropriate to use, and to the economy, in order to meet the process and the basic conditions and requirements. Specific how to judge choose frequency converter? 1, the need to control the number of motor and inverter itself. General motor pole of not more than 4 is very appropriate, or frequency converter capacity will increase appropriately. Torque characteristics, critical torque, speed torque. Under the condition of the same motor power, compared with high overload torque mode, the inverter specifications can choose derating. Electromagnetic compatibility. To reduce the mains interference, when using, can be in the middle or the inverter input circuit increase in reactor, or install the front isolation transformer. Generally when motor and frequency converter from more than 50 m should be reactor, filter in series with them or use cable shielding protection. 2, the selection of inverter power system efficiency is equal to the product of the frequency converter and motor efficiency, only under both at high efficiency at work, then the system efficiency is higher. From the perspective of efficiency, when choosing the inverter power, should pay attention to the following: the inverter power and motor power value is the most suitable, and frequency converter running under high efficiency value. In the converter power rating and motor power rating is not at the same time, the power of the inverter to be as close as possible to the power of the motor, but should be slightly bigger than the power of the motor. When the motor is a frequent starting, braking work or be in overloading starting work and more frequent, can choose big level of frequency converter, using frequency converter, run safely for a long time. After the test, the actual motor power does have a surplus, can consider to choose power less than motor power inverter, but should pay attention to the instantaneous peak current will cause overcurrent protection action. When the inverter and motor power are not same, they must adjust the energy conservation program Settings, and to achieve high energy saving effect. 3, inverter enclosure structure selection of frequency converter box structure should be compatible with environmental conditions, namely temperature, humidity, dust, must be considered factors such as ph, corrosive gas. Common have the following several kinds of structure type for the user to choose: open type IPOO type is neither chassis, used in electric cabinet or electric indoor screen, plate, frame, especially more focused when using frequency converter, choose this kind of type is better, but higher environmental requirements; Enclosed IP20 type suitable for general use, can have a small amount of dust or a little the occasion of temperature and humidity; Seal type IP45 type for industrial field conditions worse environment; Airtight type IP65 type suitable for poor environmental conditions, have water, dust and corrosive gas. 4, determine a reasonable capacity of converter capacity selection itself is a kind of energy saving measures. According to the existing data and experience, there are three more simple method: motor actual power. First of all, to determine the actual motor power, in order to select the inverter capacity. Formula method. When more than one frequency converter used in motor, should satisfy: at least want to consider the influence of an electric motor starting current, to avoid the frequency converter overcurrent trip. The motor rated current method of frequency converter. Frequency converter capacity selection process, is actually a process the best match between the inverter and motor, relatively safe is the most common, also make the converter capacity is greater than or equal to the motor rated power, but want to consider the actual power of the motor in the actual match what differ with rated power, are usually selected equipment capacity is big, but the actual ability to small, so according to the actual power of the motor to select frequency converter is reasonable, avoid to choose the frequency converter is too large, increased investment. For light load, inverter current general should press 1. 1N( N for the motor rated current) To select, or press manufacturer in the product label of the inverter output power rating matching with maximum motor power to choose. 5, the main power supply voltage and volatility. Should pay special attention to corresponding to the set values for the frequency converter low voltage protection, because in actual use, the power grid voltage is low probability. The main power supply frequency fluctuations and harmonic interference. This aspect of the interference will increase the heat loss of the inverter system, cause the noise increased, the output reduced. The inverter and motor at work, its power consumption. When for the main power supply system design, power consumption of the two factors should be taken into account. Article source: mercer ( Guangdong) Servo technology co. , LTD
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