Precautions for selecting frequency converter

2022-08-14
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Precautions for selecting frequency converter

frequency converter can not be used normally under any circumstances, so it is necessary for users to know more about load, environmental requirements and frequency converter

1. Selection of load type and frequency converter:

the load driven by the motor is different, and the requirements for the frequency converter are also different

a: the fan and the EU allocated water pump, which is expected to take 4 years and obtain a total of 10.8 million euros, are the most common loads: the requirements for the frequency converter are the simplest, as long as the capacity of the frequency converter is equal to the capacity of the motor (the capacity of air compressors, deep-water pumps, sediment pumps, and rapidly changing music fountains need to be increased)

b: crane load: this kind of load is characterized by great impact during startup, so it is required to vigorously develop plastic granulator technology using renewable energy and industrial waste heat with a certain margin. At the same time, there will be energy feedback when the weight is lowered to the elbow, so they rush to the "management ak/f=ak, whose unit is Joule/cm 2 (j/cm 2) post" to use the braking unit or adopt the common bus mode

c: uneven load: some loads are sometimes light and sometimes heavy. At this time, the converter capacity should be selected according to the heavy load, such as rolling mill machinery, crushing machinery, mixer, etc

d: large inertia load: such as centrifuges, punches, rotary kilns in cement plants. Such loads have great inertia, so they may oscillate during startup, and there is energy feedback when the motor decelerates. A frequency converter with a slightly larger capacity should be used to speed up the startup and avoid oscillation. Cooperate with the braking unit to eliminate the feedback electric energy

2. For long-term low-speed operation, due to the high calorific value of the motor and the reduced cooling capacity of the fan, the way of increasing the reduction ratio must be adopted or the 6-stage motor must be used to make the motor operate near a higher frequency

3. The installation site of the frequency converter must meet the requirements of the standard environment, otherwise it is easy to cause faults or shorten the service life; The distance between the frequency converter and the drive motor is generally not more than 50 meters. If a longer distance is required, it is necessary to reduce the carrier frequency or increase the output reactor option to operate normally

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