Energy saving technology analysis of the hottest f

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Energy saving technology analysis of frequency converter

three phase AC motor has simple structure, reliable operation and low price, and plays a great role in metallurgy, building materials, mining, chemical industry, textile, rubber, machinery and other industrial fields. There are many kinds of three-phase motor speed regulation systems, but the frequency conversion speed regulation is the most efficient, the best performance and the most widely used. It can form an AC speed regulation system with high dynamic performance to replace the DC speed regulation system. Variable frequency speed regulation is to use the frequency converter to supply power to the AC motor to realize stepless speed regulation of the AC motor in a wide range. The frequency converter can convert the AC with fixed voltage and fixed frequency into the AC with adjustable voltage and adjustable frequency. Variable frequency speed regulation replaces DC motor, which can reduce the cost and improve the reliability of operation. Variable frequency speed regulation can save 30% - 70% energy for each motor, and under the condition of constant torque, it can reduce the output power on the shaft, which not only improves the motor efficiency, but also obtains the effect of energy saving

what are the differences between PWM and PAM used in frequency converters? PWM is the abbreviation of pulse width modulation in English. It is a way of adjusting the output and waveform by changing the pulse width of the pulse train according to a certain law. PAM is the abbreviation of pulse amplitude modulation in English. It is a modulation method that changes the pulse amplitude of the pulse train according to a certain law to adjust the output value and waveform

secondly, what is the difference between voltage type and current type of frequency converter? The main circuit of frequency converter can be divided into two categories: voltage type is the frequency converter that converts the DC of voltage source into AC, and the filter of DC circuit is capacitance; Current mode is a frequency converter that converts the DC of current source into AC, and the filter of its DC circuit is inductance

then, the voltage of the frequency converter changes in proportion to the current. The torque of the asynchronous motor is generated by the interaction between the magnetic flux of the motor and the current flowing in the rotor. The international trade disputes should be properly resolved under the rated frequency. If the voltage is certain and only the frequency is reduced, the magnetic flux will be too large, the magnetic circuit will be saturated, and the motor will be burnt out in serious cases. Therefore, the frequency and voltage should be changed in proportion, that is, while changing the frequency, the output voltage of the frequency converter should be controlled to maintain a certain magnetic flux of the motor and avoid the occurrence of weak magnetic field and magnetic saturation

what is the starting current and starting torque of the motor when the frequency converter is used? Identify the manufacturer by purchasing the experimental machine: Jinan new era assaying Instrument Co., Ltd. calls for consultation: 13964077506 Yuan Gong frequency converter operates. With the acceleration of the motor, the frequency and voltage are correspondingly increased, and the starting current is limited to less than 150% of the rated current (125% to 200% according to different models). When the power frequency power supply is used for direct starting, the starting current is 6~7 times. Therefore, mechanical and electrical impact will occur. Using frequency converter transmission can start smoothly (the starting time becomes longer). The starting current is 1.2~1.5 times of the rated current, and the starting torque is 70% - 120% of the rated torque; For the frequency converter with automatic torque enhancement function, the starting torque is more than 100%, and it can start with full load

customers often find that the instruction manual says that the speed range is 60~6hz, that is, 10:1, so there is no output power below 6Hz? Power can still be output below 6Hz, but according to the motor temperature rise and starting torque, the minimum use frequency is about 6Hz. At this time, the motor can output the rated torque without causing serious heating problems. The actual output frequency (starting frequency) of the frequency converter is 0.5~3hz according to the model The energy regenerated from the motor is stored in the filter capacitor of the frequency converter. Due to the relationship between the capacity of the capacitor and the withstand voltage, the regenerative braking force of the general frequency converter is about 10% - 20% of the rated torque. If the optional brake unit is used, it can reach 50% - 100%

in the field of industrial control, most of them are electric control systems, whose final control object and actuator are motors, and the automatic control system of motors is often realized by controlling the speed. In the 1980s, with the development of power electronics technology, marketsandmarkets predicted that AC variable frequency speed regulation technology began to be applied in motor control systems in foreign countries. Since 1995, this technology has spread to Chinese Mainland, and has been more and more widely used in China in recent years. Now in foreign countries, the AC speed regulating transmission system has replaced the DC speed regulating system in the material development degree of various physical and mechanical performance tests of plastic film, rubber, wire and cable, steel, glass fiber and other materials, and has risen to the mainstream of electrical speed regulating transmission

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